Bethany R. Rohr, MD

Carpet beetle larvae of the family Dermestidae have been documented to cause both acute and delayed hypersensitivity reactions in susceptible individuals. These larvae have specialized horizontal rows of spear-shaped hairs called hastisetae, which detach easily into the surrounding environment and are small enough to travel by air. Exposure to hastisetae has been tied to adverse effects ranging from dermatitis to rhinoconjunctivitis and acute asthma, with treatment being mostly empiric and symptom based. Due to the pervasiveness of carpet beetles in homes, improved awareness of dermestid-induced manifestations is valuable for clinicians.

Beetles in the Dermestidae family do not bite humans but have been reported to cause skin reactions in addition to other symptoms typical of an allergic reaction. Skin contact with larval hairs (hastisetae) of these insects—known as carpet, larder, or hide beetles — may cause urticarial or edematous papules that are mistaken for papular urticaria or arthropod bites. ¹ There are approximately 500 to 700 species of carpet beetles worldwide. Carpet beetles are a clinically underrecognized cause of allergic contact dermatitis given their frequent presence in homes across the world. ² Carpet beetle larvae feed on shed skin, feathers, hair, wool, book bindings, felt, leather, wood, silk, and sometimes grains and thus can be found nearly anywhere. Most symptom-inducing exposures to Dermestidae beetles occur occupationally, such as in museum curators working hands-on with collection materials and workers handling infested materials such as wool. ^3,4 In-home Dermestidae exposure may lead to symptoms, especially if regularly worn clothing and bedding materials are infested. The broad palate of dermestid members has resulted in substantial contamination of stored materials such as flour and fabric in addition to the destruction of museum collections. ^5-7

The larvae of some dermestid species, most commonly of the genera Anthrenus and Dermestes, are 2 to 3 mm in length and have detachable hairlike hastisetae that shed into the surrounding environment throughout larval development (Figure 1).⁸ The hastisetae, located on the thoracic and abdominal segments (tergites), serve as a larval defense mechanism. When prodded, the round, hairy, wormlike larvae tense up and can raise their abdominal tergites while splaying the hastisetae out in a fanlike manner.⁹ Similar to porcupine quills, the hastisetae easily detach and can entrap the appendages of invertebrate predators. Hastisetae are not known to be sharp enough to puncture human skin, but friction and irritation from skin contact and superficial sticking of the hastisetae into mucous membranes and noncornified epithelium, such as in the bronchial airways, are thought to induce hypersensitivity reactions in susceptible individuals.

Additionally, hastisetae and the exoskeletons of both adult and larval dermestid beetles are composed mostly of chitin, which is highly allergenic. Chitin has been found to play a proinflammatory role in ocular inflammation, asthma, and bronchial reactivity via T helper cell (T_H2)–mediated cellular interactions.^10-12 Larvae shed their exoskeletons, including hastisetae, multiple times over the course of their development, which contributes to their potential allergen burden (Figure 2). Reports of positive prick and/or patch testing to larval components indicate some cases of both acute type 1 and delayed type 4 hypersensitivity reactions.^4,8,13

Clinical Presentation and Diagnosis

Multiple erythematous urticarial papules, papulopustules, and papulovesicles are the typical manifestations of dermestid dermatitis.^3,4,13-16 Figure 3 demonstrates several characteristic edematous papules with background erythema. Unlike the clusters seen with flea and bed bug bites, dermestid-induced lesions typically are single and scattered, with a propensity for exposed limbs and the face. Exposure to hastisetae commonly results in classic allergic symptoms including rhinitis, conjunctivitis, coughing, wheezing, sneezing, and intranasal and periocular pruritus, even in those with no personal history of atopy.^17-19 Lymphadenopathy, vasculitis, and allergic alveolitis also have been reported.²⁰ A large infestation in which many individual beetles as well as larvae can be found in 1 or more areas of the inhabited structure has been reported to cause more severe symptoms, including acute eczema, otitis externa, lymphocytic vasculitis, and allergic alveolitis, all of which resolved within 3 months of thorough deinfestation cleaning.²¹

Skin-prick and/or patch testing is not necessary for this clinical diagnosis of dermestid-induced allergic contact dermatitis. This diagnosis is bolstered by (but does not require a history of) repeated symptom induction upon performing certain activities (eg, handling taxidermy specimens) and/or in certain environments (eg, only at home). Because of individual differences in hypersensitivity to dermestid parts, it is not typical for all members of a household to be affected.

When there are multiple potential suspected allergens or an unknown cause for symptoms despite a detailed history, allergy testing can be useful in confirming a diagnosis and directing management. Immediate-onset type 1 hypersensitivity reactions are evaluated using skin-prick testing or serum IgE levels, whereas delayed type 4 hypersensitivity reactions can be evaluated using patch testing. Type 1 reactions tend to present with classic allergy symptoms, especially where there are abundant mast cells to degranulate in the skin and mucosa of the gastrointestinal and respiratory tracts; these symptoms range from mild wheezing, urticaria, periorbital pruritus, and sneezing to outright asthma, diarrhea, rhinoconjunctivitis, and even anaphylaxis. With these reactions, initial exposure to an antigen such as chitin in the hastisetae leads to an asymptomatic sensitization against the antigen in which its introduction leads to a T_H2-skewed cellular response, which promotes B-cell production of IgE antibodies. Upon subsequent exposure to this antigen, IgE antibodies bound to mast cells will lead them to degranulate with release of histamine and other proinflammatory molecules, resulting in clinical manifestations. The skin-prick test relies on introduction of potential antigens through the epidermis into the dermis with a sharp lancet to induce IgE antibody activation and then degranulation of the patient’s mast cells, resulting in a pruritic erythematous wheal. This IgE-mediated process has been shown to occur in response to dermestid larval parts among household dust, resulting in chronic coughing, sneezing, nasal pruritus, and asthma.^15,17,22

Type 4 hypersensitivity reactions are T-cell mediated and also include a sensitization phase followed by symptom manifestation upon repeat exposure; however, these reactions usually are not immediate and can take up to 72 hours after exposure to manifest.²³ This is because T cells specific to the antigen do not lead a process resulting in antibodies but instead recruit numerous other T_H1-polarized mediators upon re-exposure to activate cytotoxic CD8⁺ T cells and macrophages to attempt to neutralize the antigen. Many type 4 reactions result in mostly cutaneous manifestations, such as contact dermatitis. Patch testing involves adhering potential allergens to the skin for a time with assessments at regular intervals to evaluate the level of reaction from weakly positive to severe. At minimum, most reports of dermestid-related manifestations include a rash such as erythematous papules, and several published cases involving patch testing have yielded positive results to various preparations of larval parts.^3,14,21

Management and Treatment

Prevention of dermestid exposure is difficult given the myriad materials eaten by the larvae. An insect exterminator should verify and treat a carpet beetle infestation, while a dermatologist can treat symptomatic individuals. Treatment is driven by the severity of the patient’s discomfort and is aimed at both symptomatic relief and reducing dermestid exposure moving forward. Although in certain environments it will be nearly impossible to eradicate Dermestidae, cleaning thoroughly and regularly may go far to reduce exposure and associated symptoms.

Clothing and other materials such as bedding that will have direct skin contact should be washed to remove hastisetae and be stored in airtight containers in addition to items made with animal fibers, such as wool sweaters and down blankets. Mattresses, flooring, rugs, curtains, and other amenable areas should be vacuumed thoroughly, and the vacuum bag should be placed in the trash afterward. Protective pillow and mattress covers should be used. Stuffed animals in infested areas should be thrown away if not able to be completely washed and dried. Air conditioning systems may spread larval hairs away from the site of infestation and should be cleaned as much as possible. Surfaces where beetles and larvae also are commonly seen, such as windowsills, and hidden among closet and pantry items should also be wiped clean to remove both insects and potential substrate. In one case, scraping the wood flooring and applying a thick coat of varnish in addition to removing all stuffed animals from an affected individual’s home allowed for resolution of symptoms.¹⁷

Treatment for symptoms includes topical anti-inflammatory agents and/or oral antihistamines, with improvement in symptoms typically occurring within days and resolution dependent on level of exposure moving forward.

Final Thoughts

There is a broad overlap between dermestid habitats and human-occupied environments; thus, the opportunities for exposure and sensitization to allergenic dermestid parts are numerous. Dermatologists should be aware of the possible manifestations from dermestid exposure.

Carpet beetle larvae of the family Dermestidae have been documented to cause both acute and delayed hypersensitivity reactions in susceptible individuals. These larvae have specialized horizontal rows of spear-shaped hairs called hastisetae, which detach easily into the surrounding environment and are small enough to travel by air. Exposure to hastisetae has been tied to adverse effects ranging from dermatitis to rhinoconjunctivitis and acute asthma, with treatment being mostly empiric and symptom based. Due to the pervasiveness of carpet beetles in homes, improved awareness of dermestid-induced manifestations is valuable for clinicians.

Beetles in the Dermestidae family do not bite humans but have been reported to cause skin reactions in addition to other symptoms typical of an allergic reaction. Skin contact with larval hairs (hastisetae) of these insects—known as carpet, larder, or hide beetles — may cause urticarial or edematous papules that are mistaken for papular urticaria or arthropod bites. ¹ There are approximately 500 to 700 species of carpet beetles worldwide. Carpet beetles are a clinically underrecognized cause of allergic contact dermatitis given their frequent presence in homes across the world. ² Carpet beetle larvae feed on shed skin, feathers, hair, wool, book bindings, felt, leather, wood, silk, and sometimes grains and thus can be found nearly anywhere. Most symptom-inducing exposures to Dermestidae beetles occur occupationally, such as in museum curators working hands-on with collection materials and workers handling infested materials such as wool. ^3,4 In-home Dermestidae exposure may lead to symptoms, especially if regularly worn clothing and bedding materials are infested. The broad palate of dermestid members has resulted in substantial contamination of stored materials such as flour and fabric in addition to the destruction of museum collections. ^5-7

The larvae of some dermestid species, most commonly of the genera Anthrenus and Dermestes, are 2 to 3 mm in length and have detachable hairlike hastisetae that shed into the surrounding environment throughout larval development (Figure 1).⁸ The hastisetae, located on the thoracic and abdominal segments (tergites), serve as a larval defense mechanism. When prodded, the round, hairy, wormlike larvae tense up and can raise their abdominal tergites while splaying the hastisetae out in a fanlike manner.⁹ Similar to porcupine quills, the hastisetae easily detach and can entrap the appendages of invertebrate predators. Hastisetae are not known to be sharp enough to puncture human skin, but friction and irritation from skin contact and superficial sticking of the hastisetae into mucous membranes and noncornified epithelium, such as in the bronchial airways, are thought to induce hypersensitivity reactions in susceptible individuals.

Additionally, hastisetae and the exoskeletons of both adult and larval dermestid beetles are composed mostly of chitin, which is highly allergenic. Chitin has been found to play a proinflammatory role in ocular inflammation, asthma, and bronchial reactivity via T helper cell (T_H2)–mediated cellular interactions.^10-12 Larvae shed their exoskeletons, including hastisetae, multiple times over the course of their development, which contributes to their potential allergen burden (Figure 2). Reports of positive prick and/or patch testing to larval components indicate some cases of both acute type 1 and delayed type 4 hypersensitivity reactions.^4,8,13

Clinical Presentation and Diagnosis

Multiple erythematous urticarial papules, papulopustules, and papulovesicles are the typical manifestations of dermestid dermatitis.^3,4,13-16 Figure 3 demonstrates several characteristic edematous papules with background erythema. Unlike the clusters seen with flea and bed bug bites, dermestid-induced lesions typically are single and scattered, with a propensity for exposed limbs and the face. Exposure to hastisetae commonly results in classic allergic symptoms including rhinitis, conjunctivitis, coughing, wheezing, sneezing, and intranasal and periocular pruritus, even in those with no personal history of atopy.^17-19 Lymphadenopathy, vasculitis, and allergic alveolitis also have been reported.²⁰ A large infestation in which many individual beetles as well as larvae can be found in 1 or more areas of the inhabited structure has been reported to cause more severe symptoms, including acute eczema, otitis externa, lymphocytic vasculitis, and allergic alveolitis, all of which resolved within 3 months of thorough deinfestation cleaning.²¹

Skin-prick and/or patch testing is not necessary for this clinical diagnosis of dermestid-induced allergic contact dermatitis. This diagnosis is bolstered by (but does not require a history of) repeated symptom induction upon performing certain activities (eg, handling taxidermy specimens) and/or in certain environments (eg, only at home). Because of individual differences in hypersensitivity to dermestid parts, it is not typical for all members of a household to be affected.

When there are multiple potential suspected allergens or an unknown cause for symptoms despite a detailed history, allergy testing can be useful in confirming a diagnosis and directing management. Immediate-onset type 1 hypersensitivity reactions are evaluated using skin-prick testing or serum IgE levels, whereas delayed type 4 hypersensitivity reactions can be evaluated using patch testing. Type 1 reactions tend to present with classic allergy symptoms, especially where there are abundant mast cells to degranulate in the skin and mucosa of the gastrointestinal and respiratory tracts; these symptoms range from mild wheezing, urticaria, periorbital pruritus, and sneezing to outright asthma, diarrhea, rhinoconjunctivitis, and even anaphylaxis. With these reactions, initial exposure to an antigen such as chitin in the hastisetae leads to an asymptomatic sensitization against the antigen in which its introduction leads to a T_H2-skewed cellular response, which promotes B-cell production of IgE antibodies. Upon subsequent exposure to this antigen, IgE antibodies bound to mast cells will lead them to degranulate with release of histamine and other proinflammatory molecules, resulting in clinical manifestations. The skin-prick test relies on introduction of potential antigens through the epidermis into the dermis with a sharp lancet to induce IgE antibody activation and then degranulation of the patient’s mast cells, resulting in a pruritic erythematous wheal. This IgE-mediated process has been shown to occur in response to dermestid larval parts among household dust, resulting in chronic coughing, sneezing, nasal pruritus, and asthma.^15,17,22

Type 4 hypersensitivity reactions are T-cell mediated and also include a sensitization phase followed by symptom manifestation upon repeat exposure; however, these reactions usually are not immediate and can take up to 72 hours after exposure to manifest.²³ This is because T cells specific to the antigen do not lead a process resulting in antibodies but instead recruit numerous other T_H1-polarized mediators upon re-exposure to activate cytotoxic CD8⁺ T cells and macrophages to attempt to neutralize the antigen. Many type 4 reactions result in mostly cutaneous manifestations, such as contact dermatitis. Patch testing involves adhering potential allergens to the skin for a time with assessments at regular intervals to evaluate the level of reaction from weakly positive to severe. At minimum, most reports of dermestid-related manifestations include a rash such as erythematous papules, and several published cases involving patch testing have yielded positive results to various preparations of larval parts.^3,14,21

Management and Treatment

Prevention of dermestid exposure is difficult given the myriad materials eaten by the larvae. An insect exterminator should verify and treat a carpet beetle infestation, while a dermatologist can treat symptomatic individuals. Treatment is driven by the severity of the patient’s discomfort and is aimed at both symptomatic relief and reducing dermestid exposure moving forward. Although in certain environments it will be nearly impossible to eradicate Dermestidae, cleaning thoroughly and regularly may go far to reduce exposure and associated symptoms.

Clothing and other materials such as bedding that will have direct skin contact should be washed to remove hastisetae and be stored in airtight containers in addition to items made with animal fibers, such as wool sweaters and down blankets. Mattresses, flooring, rugs, curtains, and other amenable areas should be vacuumed thoroughly, and the vacuum bag should be placed in the trash afterward. Protective pillow and mattress covers should be used. Stuffed animals in infested areas should be thrown away if not able to be completely washed and dried. Air conditioning systems may spread larval hairs away from the site of infestation and should be cleaned as much as possible. Surfaces where beetles and larvae also are commonly seen, such as windowsills, and hidden among closet and pantry items should also be wiped clean to remove both insects and potential substrate. In one case, scraping the wood flooring and applying a thick coat of varnish in addition to removing all stuffed animals from an affected individual’s home allowed for resolution of symptoms.¹⁷

Treatment for symptoms includes topical anti-inflammatory agents and/or oral antihistamines, with improvement in symptoms typically occurring within days and resolution dependent on level of exposure moving forward.

Final Thoughts

There is a broad overlap between dermestid habitats and human-occupied environments; thus, the opportunities for exposure and sensitization to allergenic dermestid parts are numerous. Dermatologists should be aware of the possible manifestations from dermestid exposure.

Carpet beetle larvae of the family Dermestidae have been documented to cause both acute and delayed hypersensitivity reactions in susceptible individuals. These larvae have specialized horizontal rows of spear-shaped hairs called hastisetae, which detach easily into the surrounding environment and are small enough to travel by air. Exposure to hastisetae has been tied to adverse effects ranging from dermatitis to rhinoconjunctivitis and acute asthma, with treatment being mostly empiric and symptom based. Due to the pervasiveness of carpet beetles in homes, improved awareness of dermestid-induced manifestations is valuable for clinicians.

Beetles in the Dermestidae family do not bite humans but have been reported to cause skin reactions in addition to other symptoms typical of an allergic reaction. Skin contact with larval hairs (hastisetae) of these insects—known as carpet, larder, or hide beetles — may cause urticarial or edematous papules that are mistaken for papular urticaria or arthropod bites. ¹ There are approximately 500 to 700 species of carpet beetles worldwide. Carpet beetles are a clinically underrecognized cause of allergic contact dermatitis given their frequent presence in homes across the world. ² Carpet beetle larvae feed on shed skin, feathers, hair, wool, book bindings, felt, leather, wood, silk, and sometimes grains and thus can be found nearly anywhere. Most symptom-inducing exposures to Dermestidae beetles occur occupationally, such as in museum curators working hands-on with collection materials and workers handling infested materials such as wool. ^3,4 In-home Dermestidae exposure may lead to symptoms, especially if regularly worn clothing and bedding materials are infested. The broad palate of dermestid members has resulted in substantial contamination of stored materials such as flour and fabric in addition to the destruction of museum collections. ^5-7

The larvae of some dermestid species, most commonly of the genera Anthrenus and Dermestes, are 2 to 3 mm in length and have detachable hairlike hastisetae that shed into the surrounding environment throughout larval development (Figure 1).⁸ The hastisetae, located on the thoracic and abdominal segments (tergites), serve as a larval defense mechanism. When prodded, the round, hairy, wormlike larvae tense up and can raise their abdominal tergites while splaying the hastisetae out in a fanlike manner.⁹ Similar to porcupine quills, the hastisetae easily detach and can entrap the appendages of invertebrate predators. Hastisetae are not known to be sharp enough to puncture human skin, but friction and irritation from skin contact and superficial sticking of the hastisetae into mucous membranes and noncornified epithelium, such as in the bronchial airways, are thought to induce hypersensitivity reactions in susceptible individuals.

Additionally, hastisetae and the exoskeletons of both adult and larval dermestid beetles are composed mostly of chitin, which is highly allergenic. Chitin has been found to play a proinflammatory role in ocular inflammation, asthma, and bronchial reactivity via T helper cell (T_H2)–mediated cellular interactions.^10-12 Larvae shed their exoskeletons, including hastisetae, multiple times over the course of their development, which contributes to their potential allergen burden (Figure 2). Reports of positive prick and/or patch testing to larval components indicate some cases of both acute type 1 and delayed type 4 hypersensitivity reactions.^4,8,13

Clinical Presentation and Diagnosis

Multiple erythematous urticarial papules, papulopustules, and papulovesicles are the typical manifestations of dermestid dermatitis.^3,4,13-16 Figure 3 demonstrates several characteristic edematous papules with background erythema. Unlike the clusters seen with flea and bed bug bites, dermestid-induced lesions typically are single and scattered, with a propensity for exposed limbs and the face. Exposure to hastisetae commonly results in classic allergic symptoms including rhinitis, conjunctivitis, coughing, wheezing, sneezing, and intranasal and periocular pruritus, even in those with no personal history of atopy.^17-19 Lymphadenopathy, vasculitis, and allergic alveolitis also have been reported.²⁰ A large infestation in which many individual beetles as well as larvae can be found in 1 or more areas of the inhabited structure has been reported to cause more severe symptoms, including acute eczema, otitis externa, lymphocytic vasculitis, and allergic alveolitis, all of which resolved within 3 months of thorough deinfestation cleaning.²¹

Skin-prick and/or patch testing is not necessary for this clinical diagnosis of dermestid-induced allergic contact dermatitis. This diagnosis is bolstered by (but does not require a history of) repeated symptom induction upon performing certain activities (eg, handling taxidermy specimens) and/or in certain environments (eg, only at home). Because of individual differences in hypersensitivity to dermestid parts, it is not typical for all members of a household to be affected.

When there are multiple potential suspected allergens or an unknown cause for symptoms despite a detailed history, allergy testing can be useful in confirming a diagnosis and directing management. Immediate-onset type 1 hypersensitivity reactions are evaluated using skin-prick testing or serum IgE levels, whereas delayed type 4 hypersensitivity reactions can be evaluated using patch testing. Type 1 reactions tend to present with classic allergy symptoms, especially where there are abundant mast cells to degranulate in the skin and mucosa of the gastrointestinal and respiratory tracts; these symptoms range from mild wheezing, urticaria, periorbital pruritus, and sneezing to outright asthma, diarrhea, rhinoconjunctivitis, and even anaphylaxis. With these reactions, initial exposure to an antigen such as chitin in the hastisetae leads to an asymptomatic sensitization against the antigen in which its introduction leads to a T_H2-skewed cellular response, which promotes B-cell production of IgE antibodies. Upon subsequent exposure to this antigen, IgE antibodies bound to mast cells will lead them to degranulate with release of histamine and other proinflammatory molecules, resulting in clinical manifestations. The skin-prick test relies on introduction of potential antigens through the epidermis into the dermis with a sharp lancet to induce IgE antibody activation and then degranulation of the patient’s mast cells, resulting in a pruritic erythematous wheal. This IgE-mediated process has been shown to occur in response to dermestid larval parts among household dust, resulting in chronic coughing, sneezing, nasal pruritus, and asthma.^15,17,22

Type 4 hypersensitivity reactions are T-cell mediated and also include a sensitization phase followed by symptom manifestation upon repeat exposure; however, these reactions usually are not immediate and can take up to 72 hours after exposure to manifest.²³ This is because T cells specific to the antigen do not lead a process resulting in antibodies but instead recruit numerous other T_H1-polarized mediators upon re-exposure to activate cytotoxic CD8⁺ T cells and macrophages to attempt to neutralize the antigen. Many type 4 reactions result in mostly cutaneous manifestations, such as contact dermatitis. Patch testing involves adhering potential allergens to the skin for a time with assessments at regular intervals to evaluate the level of reaction from weakly positive to severe. At minimum, most reports of dermestid-related manifestations include a rash such as erythematous papules, and several published cases involving patch testing have yielded positive results to various preparations of larval parts.^3,14,21

Management and Treatment

Prevention of dermestid exposure is difficult given the myriad materials eaten by the larvae. An insect exterminator should verify and treat a carpet beetle infestation, while a dermatologist can treat symptomatic individuals. Treatment is driven by the severity of the patient’s discomfort and is aimed at both symptomatic relief and reducing dermestid exposure moving forward. Although in certain environments it will be nearly impossible to eradicate Dermestidae, cleaning thoroughly and regularly may go far to reduce exposure and associated symptoms.

Clothing and other materials such as bedding that will have direct skin contact should be washed to remove hastisetae and be stored in airtight containers in addition to items made with animal fibers, such as wool sweaters and down blankets. Mattresses, flooring, rugs, curtains, and other amenable areas should be vacuumed thoroughly, and the vacuum bag should be placed in the trash afterward. Protective pillow and mattress covers should be used. Stuffed animals in infested areas should be thrown away if not able to be completely washed and dried. Air conditioning systems may spread larval hairs away from the site of infestation and should be cleaned as much as possible. Surfaces where beetles and larvae also are commonly seen, such as windowsills, and hidden among closet and pantry items should also be wiped clean to remove both insects and potential substrate. In one case, scraping the wood flooring and applying a thick coat of varnish in addition to removing all stuffed animals from an affected individual’s home allowed for resolution of symptoms.¹⁷

Treatment for symptoms includes topical anti-inflammatory agents and/or oral antihistamines, with improvement in symptoms typically occurring within days and resolution dependent on level of exposure moving forward.

Final Thoughts

There is a broad overlap between dermestid habitats and human-occupied environments; thus, the opportunities for exposure and sensitization to allergenic dermestid parts are numerous. Dermatologists should be aware of the possible manifestations from dermestid exposure.

Incidence and Characteristics

The noble false widow spider (Steatoda nobilis) is one of the world’s most invasive spider species, having spread across the globe from Madeira and the Canary Islands into the North Atlantic.^1,2Steatoda comprise multiple species of false widow spiders, named for their resemblance to black widow spiders (Latrodectus). The noble false widow spider is the dominant species in buildings in southern Ireland and Great Britain, with a population surge in 2018 that caused multiple temporary school closures in London, England, for fumigation.³ The noble false widow spider was first documented in the United States in Ventura County, California, in 2011, with numerous specimens found in urban areas (eg, in parks, underneath garbage cans) closer to the coastline as well as farther inland. The species may have been introduced to this area by way of Port Hueneme, a city in California with a US naval base with routes to various other military bases in Western Europe.⁴ Given its already rapid expansion outside of the United States with a concurrent rise in bite reports, dermatologists should be familiar with these invasive and potentially dangerous arachnids.

The spread of noble false widow spiders is assisted by their wide range of temperature tolerance and ability to survive for months with little food and no water. They can live for several years, with one report of a noble false widow spider living up to 7 years.⁵ These spiders are found inside homes and buildings year-round, and they prefer to build their webs in an elevated position such as the top corner of a room. Steatoda weave tangle webs with crisscrossing threads that often have a denser middle section.⁵

Noble false widow spiders are sexually dimorphic, with males typically no larger than 1-cm long and females up to 1.4-cm long. They have a dark brown to black thorax and brown abdomen with red-brown legs. Males have brighter cream-colored abdominal markings than females, who lack markings altogether on their distinctive globular abdomen (Figure). The abdominal markings are known to resemble a skull or house.

©ePhotocorp / iStock / Getty Images Plus.

Although noble false widow spiders are not exclusively synanthropic, they can be found in any crevice in homes or other structures where there are humans such as office buildings.^5-7 Up until the last 20 years, reports of bites from noble false widow spiders worldwide were few and far between. In Great Britain, the spiders were first considered to be common in the 1980s, with recent evidence of an urban population boom in the last 5 to 10 years that has coincided with an increase in bite reports.^5,8,9

Clinical Significance

Most bites occur in a defensive manner, such as when humans perform activities that disturb the hiding space, cause vibrations in the web, or compress the body of the arachnid. Most envenomations in Great Britain occur while the individual is in bed, though they also may occur during other activities that disturb the spider, such as moving boxes or putting on a pair of pants.⁵ Occupational exposure to noble false widow spiders may soon be a concern for those involved in construction, carpentry, cleaning, and decorating given their recent invasive spread into the United States.

The venom from these spiders is neurotoxic and cytotoxic, causing moderate to intense pain that may resemble a wasp sting. The incidence of steatodism—which can include symptoms of pain in addition to fever, hypotension, headache, lethargy, nausea, localized diaphoresis, abdominal pain, paresthesias, and malaise—is unknown but reportedly rare.^5,10 There are considerable similarities between Steatoda and true black widow spider venom, which explains the symptom overlap with latrodectism. There are reports of severe debilitation lasting weeks due to pain and decreased affected limb movement after bites from noble false widow spiders.^10-12

Nearly all noble false widow spider bite reports describe immediate pain upon bite/envenomation, which is unlike the delayed pain from a black widow spider bite (after 10 minutes or more).^6,13,14 Erythema and swelling occur around a pale raised site of envenomation lasting up to 72 hours. The bite site may be highly tender and blister or ulcerate, with reports of cellulitis and local skin necrosis.^7,15 Pruritus during this period can be intense, and excoriation increases the risk for complications such as infection. Reports of anaphylaxis following a noble false widow spider bite are rare.^5,16 The incidence of bites may be underreported due to the lack of proper identification of the responsible arachnid for those who do not seek care or require hospitalization, though this is not unique to Steatoda.

There are reports of secondary infection after bites and even cases of limb amputation, septicemia, and death.^14,17 However, it is unknown if noble false widow spiders are vectors for bacteria transmitted during envenomation, and infection likely is secondary to scratching or inadequate wound care.^18,19 Potentially pathogenic bacteria have been isolated from the body surfaces of the noble false widow spider, including Pseudomonas putida, Staphylococcus capitis, and Staphylococcus epidermidis.²⁰ Fortunately, most captured cases (ie, events in which the biting arachnid was properly identified) report symptoms ranging from mild to moderate in severity without the need for hospitalization. A series of 24 reports revealed that all individuals experienced sharp pain upon the initial bite followed by erythema, and 18 of them experienced considerable swelling of the area soon thereafter. One individual experienced temporary paralysis of the affected limb, and 3 individuals experienced hypotension or hypertension in addition to fever, skin necrosis, or cellulitis.¹⁴

Treatment

The envenomation site should be washed with antibacterial soap and warm water and should be kept clean to prevent infection. There is no evidence that tight pressure bandaging of these bite sites will restrict venom flow; because it may worsen pain in the area, pressure bandaging is not recommended. When possible, the arachnid should be collected for identification. Supportive care is warranted for symptoms of pain, erythema, and swelling, with the use of cool compresses, oral pain relievers (eg, nonsteroidal anti-inflammatory drugs, acetaminophen), topical anesthetic (eg, lidocaine), or antihistamines as needed.

Urgent care is warranted for patients who experience severe symptoms of steatodism such as hypertension, lymphadenopathy, paresthesia, or limb paralysis. Limited reports show onset of this distress typically within an hour of envenomation. Treatments analogous to those for latrodectism including muscle relaxers and pain medications have demonstrated rapid attenuation of symptoms upon intramuscular administration of antivenom made from Latrodectus species.^21-23

Signs of infection warrant bacterial culture with antibiotic susceptibilities to ensure adequate treatment.²⁰ Infections from spider bites can present a few days to a week following envenomation. Symptoms may include spreading redness or an enlarging wound site, pus formation, worsening or unrelenting pain after 24 hours, fevers, flulike symptoms, and muscle cramps.

Final Thoughts

Symptoms from noble false widow spider bites range widely from localized pain, swelling, and erythema to ulceration, necrosis, and rarely death related to secondary infection. Because of their invasive spread in Europe and increasing presence in the United States, it is important to be aware of the possibility of noble false widow spider bites to manage reactions that may quickly lead to morbidity.

Incidence and Characteristics

The noble false widow spider (Steatoda nobilis) is one of the world’s most invasive spider species, having spread across the globe from Madeira and the Canary Islands into the North Atlantic.^1,2Steatoda comprise multiple species of false widow spiders, named for their resemblance to black widow spiders (Latrodectus). The noble false widow spider is the dominant species in buildings in southern Ireland and Great Britain, with a population surge in 2018 that caused multiple temporary school closures in London, England, for fumigation.³ The noble false widow spider was first documented in the United States in Ventura County, California, in 2011, with numerous specimens found in urban areas (eg, in parks, underneath garbage cans) closer to the coastline as well as farther inland. The species may have been introduced to this area by way of Port Hueneme, a city in California with a US naval base with routes to various other military bases in Western Europe.⁴ Given its already rapid expansion outside of the United States with a concurrent rise in bite reports, dermatologists should be familiar with these invasive and potentially dangerous arachnids.

The spread of noble false widow spiders is assisted by their wide range of temperature tolerance and ability to survive for months with little food and no water. They can live for several years, with one report of a noble false widow spider living up to 7 years.⁵ These spiders are found inside homes and buildings year-round, and they prefer to build their webs in an elevated position such as the top corner of a room. Steatoda weave tangle webs with crisscrossing threads that often have a denser middle section.⁵

Noble false widow spiders are sexually dimorphic, with males typically no larger than 1-cm long and females up to 1.4-cm long. They have a dark brown to black thorax and brown abdomen with red-brown legs. Males have brighter cream-colored abdominal markings than females, who lack markings altogether on their distinctive globular abdomen (Figure). The abdominal markings are known to resemble a skull or house.

©ePhotocorp / iStock / Getty Images Plus.

Although noble false widow spiders are not exclusively synanthropic, they can be found in any crevice in homes or other structures where there are humans such as office buildings.^5-7 Up until the last 20 years, reports of bites from noble false widow spiders worldwide were few and far between. In Great Britain, the spiders were first considered to be common in the 1980s, with recent evidence of an urban population boom in the last 5 to 10 years that has coincided with an increase in bite reports.^5,8,9

Clinical Significance

Most bites occur in a defensive manner, such as when humans perform activities that disturb the hiding space, cause vibrations in the web, or compress the body of the arachnid. Most envenomations in Great Britain occur while the individual is in bed, though they also may occur during other activities that disturb the spider, such as moving boxes or putting on a pair of pants.⁵ Occupational exposure to noble false widow spiders may soon be a concern for those involved in construction, carpentry, cleaning, and decorating given their recent invasive spread into the United States.

The venom from these spiders is neurotoxic and cytotoxic, causing moderate to intense pain that may resemble a wasp sting. The incidence of steatodism—which can include symptoms of pain in addition to fever, hypotension, headache, lethargy, nausea, localized diaphoresis, abdominal pain, paresthesias, and malaise—is unknown but reportedly rare.^5,10 There are considerable similarities between Steatoda and true black widow spider venom, which explains the symptom overlap with latrodectism. There are reports of severe debilitation lasting weeks due to pain and decreased affected limb movement after bites from noble false widow spiders.^10-12

Nearly all noble false widow spider bite reports describe immediate pain upon bite/envenomation, which is unlike the delayed pain from a black widow spider bite (after 10 minutes or more).^6,13,14 Erythema and swelling occur around a pale raised site of envenomation lasting up to 72 hours. The bite site may be highly tender and blister or ulcerate, with reports of cellulitis and local skin necrosis.^7,15 Pruritus during this period can be intense, and excoriation increases the risk for complications such as infection. Reports of anaphylaxis following a noble false widow spider bite are rare.^5,16 The incidence of bites may be underreported due to the lack of proper identification of the responsible arachnid for those who do not seek care or require hospitalization, though this is not unique to Steatoda.

There are reports of secondary infection after bites and even cases of limb amputation, septicemia, and death.^14,17 However, it is unknown if noble false widow spiders are vectors for bacteria transmitted during envenomation, and infection likely is secondary to scratching or inadequate wound care.^18,19 Potentially pathogenic bacteria have been isolated from the body surfaces of the noble false widow spider, including Pseudomonas putida, Staphylococcus capitis, and Staphylococcus epidermidis.²⁰ Fortunately, most captured cases (ie, events in which the biting arachnid was properly identified) report symptoms ranging from mild to moderate in severity without the need for hospitalization. A series of 24 reports revealed that all individuals experienced sharp pain upon the initial bite followed by erythema, and 18 of them experienced considerable swelling of the area soon thereafter. One individual experienced temporary paralysis of the affected limb, and 3 individuals experienced hypotension or hypertension in addition to fever, skin necrosis, or cellulitis.¹⁴

Treatment

The envenomation site should be washed with antibacterial soap and warm water and should be kept clean to prevent infection. There is no evidence that tight pressure bandaging of these bite sites will restrict venom flow; because it may worsen pain in the area, pressure bandaging is not recommended. When possible, the arachnid should be collected for identification. Supportive care is warranted for symptoms of pain, erythema, and swelling, with the use of cool compresses, oral pain relievers (eg, nonsteroidal anti-inflammatory drugs, acetaminophen), topical anesthetic (eg, lidocaine), or antihistamines as needed.

Urgent care is warranted for patients who experience severe symptoms of steatodism such as hypertension, lymphadenopathy, paresthesia, or limb paralysis. Limited reports show onset of this distress typically within an hour of envenomation. Treatments analogous to those for latrodectism including muscle relaxers and pain medications have demonstrated rapid attenuation of symptoms upon intramuscular administration of antivenom made from Latrodectus species.^21-23

Signs of infection warrant bacterial culture with antibiotic susceptibilities to ensure adequate treatment.²⁰ Infections from spider bites can present a few days to a week following envenomation. Symptoms may include spreading redness or an enlarging wound site, pus formation, worsening or unrelenting pain after 24 hours, fevers, flulike symptoms, and muscle cramps.

Final Thoughts

Symptoms from noble false widow spider bites range widely from localized pain, swelling, and erythema to ulceration, necrosis, and rarely death related to secondary infection. Because of their invasive spread in Europe and increasing presence in the United States, it is important to be aware of the possibility of noble false widow spider bites to manage reactions that may quickly lead to morbidity.

Incidence and Characteristics

The noble false widow spider (Steatoda nobilis) is one of the world’s most invasive spider species, having spread across the globe from Madeira and the Canary Islands into the North Atlantic.^1,2Steatoda comprise multiple species of false widow spiders, named for their resemblance to black widow spiders (Latrodectus). The noble false widow spider is the dominant species in buildings in southern Ireland and Great Britain, with a population surge in 2018 that caused multiple temporary school closures in London, England, for fumigation.³ The noble false widow spider was first documented in the United States in Ventura County, California, in 2011, with numerous specimens found in urban areas (eg, in parks, underneath garbage cans) closer to the coastline as well as farther inland. The species may have been introduced to this area by way of Port Hueneme, a city in California with a US naval base with routes to various other military bases in Western Europe.⁴ Given its already rapid expansion outside of the United States with a concurrent rise in bite reports, dermatologists should be familiar with these invasive and potentially dangerous arachnids.

The spread of noble false widow spiders is assisted by their wide range of temperature tolerance and ability to survive for months with little food and no water. They can live for several years, with one report of a noble false widow spider living up to 7 years.⁵ These spiders are found inside homes and buildings year-round, and they prefer to build their webs in an elevated position such as the top corner of a room. Steatoda weave tangle webs with crisscrossing threads that often have a denser middle section.⁵

Noble false widow spiders are sexually dimorphic, with males typically no larger than 1-cm long and females up to 1.4-cm long. They have a dark brown to black thorax and brown abdomen with red-brown legs. Males have brighter cream-colored abdominal markings than females, who lack markings altogether on their distinctive globular abdomen (Figure). The abdominal markings are known to resemble a skull or house.

©ePhotocorp / iStock / Getty Images Plus.

Although noble false widow spiders are not exclusively synanthropic, they can be found in any crevice in homes or other structures where there are humans such as office buildings.^5-7 Up until the last 20 years, reports of bites from noble false widow spiders worldwide were few and far between. In Great Britain, the spiders were first considered to be common in the 1980s, with recent evidence of an urban population boom in the last 5 to 10 years that has coincided with an increase in bite reports.^5,8,9

Clinical Significance

Most bites occur in a defensive manner, such as when humans perform activities that disturb the hiding space, cause vibrations in the web, or compress the body of the arachnid. Most envenomations in Great Britain occur while the individual is in bed, though they also may occur during other activities that disturb the spider, such as moving boxes or putting on a pair of pants.⁵ Occupational exposure to noble false widow spiders may soon be a concern for those involved in construction, carpentry, cleaning, and decorating given their recent invasive spread into the United States.

The venom from these spiders is neurotoxic and cytotoxic, causing moderate to intense pain that may resemble a wasp sting. The incidence of steatodism—which can include symptoms of pain in addition to fever, hypotension, headache, lethargy, nausea, localized diaphoresis, abdominal pain, paresthesias, and malaise—is unknown but reportedly rare.^5,10 There are considerable similarities between Steatoda and true black widow spider venom, which explains the symptom overlap with latrodectism. There are reports of severe debilitation lasting weeks due to pain and decreased affected limb movement after bites from noble false widow spiders.^10-12

Nearly all noble false widow spider bite reports describe immediate pain upon bite/envenomation, which is unlike the delayed pain from a black widow spider bite (after 10 minutes or more).^6,13,14 Erythema and swelling occur around a pale raised site of envenomation lasting up to 72 hours. The bite site may be highly tender and blister or ulcerate, with reports of cellulitis and local skin necrosis.^7,15 Pruritus during this period can be intense, and excoriation increases the risk for complications such as infection. Reports of anaphylaxis following a noble false widow spider bite are rare.^5,16 The incidence of bites may be underreported due to the lack of proper identification of the responsible arachnid for those who do not seek care or require hospitalization, though this is not unique to Steatoda.

There are reports of secondary infection after bites and even cases of limb amputation, septicemia, and death.^14,17 However, it is unknown if noble false widow spiders are vectors for bacteria transmitted during envenomation, and infection likely is secondary to scratching or inadequate wound care.^18,19 Potentially pathogenic bacteria have been isolated from the body surfaces of the noble false widow spider, including Pseudomonas putida, Staphylococcus capitis, and Staphylococcus epidermidis.²⁰ Fortunately, most captured cases (ie, events in which the biting arachnid was properly identified) report symptoms ranging from mild to moderate in severity without the need for hospitalization. A series of 24 reports revealed that all individuals experienced sharp pain upon the initial bite followed by erythema, and 18 of them experienced considerable swelling of the area soon thereafter. One individual experienced temporary paralysis of the affected limb, and 3 individuals experienced hypotension or hypertension in addition to fever, skin necrosis, or cellulitis.¹⁴

Treatment

The envenomation site should be washed with antibacterial soap and warm water and should be kept clean to prevent infection. There is no evidence that tight pressure bandaging of these bite sites will restrict venom flow; because it may worsen pain in the area, pressure bandaging is not recommended. When possible, the arachnid should be collected for identification. Supportive care is warranted for symptoms of pain, erythema, and swelling, with the use of cool compresses, oral pain relievers (eg, nonsteroidal anti-inflammatory drugs, acetaminophen), topical anesthetic (eg, lidocaine), or antihistamines as needed.

Urgent care is warranted for patients who experience severe symptoms of steatodism such as hypertension, lymphadenopathy, paresthesia, or limb paralysis. Limited reports show onset of this distress typically within an hour of envenomation. Treatments analogous to those for latrodectism including muscle relaxers and pain medications have demonstrated rapid attenuation of symptoms upon intramuscular administration of antivenom made from Latrodectus species.^21-23

Signs of infection warrant bacterial culture with antibiotic susceptibilities to ensure adequate treatment.²⁰ Infections from spider bites can present a few days to a week following envenomation. Symptoms may include spreading redness or an enlarging wound site, pus formation, worsening or unrelenting pain after 24 hours, fevers, flulike symptoms, and muscle cramps.

Final Thoughts

Symptoms from noble false widow spider bites range widely from localized pain, swelling, and erythema to ulceration, necrosis, and rarely death related to secondary infection. Because of their invasive spread in Europe and increasing presence in the United States, it is important to be aware of the possibility of noble false widow spider bites to manage reactions that may quickly lead to morbidity.

To the Editor:

Wolf isotopic response describes the development of a skin disorder at the site of another healed and unrelated skin disease. Skin disorders presenting as isotopic responses have included inflammatory, malignant, granulomatous, and infectious processes. Discoid lupus erythematosus (DLE) is a rare isotopic response. We report a cutaneous lupus erythematosus–like isotopic response that presented at the site of a recent herpes zoster infection in a liver transplant recipient.

A 74-year-old immunocompromised woman was referred to the dermatology clinic for evaluation of a rash on the right leg. She was being treated with maintenance valganciclovir due to cytomegalovirus viremia, as well as tacrolimus, azathioprine, and prednisone following liver transplantation due to autoimmune hepatitis for 8 months prior to presentation. Eighteen days prior to the current presentation, she was clinically diagnosed with herpes zoster. As the grouped vesicles from the herpes zoster resolved, she developed pink scaly papules in the same distribution as the original vesicular eruption.

Physical examination revealed numerous erythematous, 2- to 3-mm, scaly papules that coalesced into small plaques with serous crusts; they originated above the supragluteal cleft and extended rightward in the L3 and L4 dermatomes to the right knee (Figure 1). A 3-mm punch biopsy specimen was obtained from the right anterior thigh. Histologic analysis revealed interface lymphocytic inflammation with squamatization of basal keratinocytes, basement membrane thickening, and follicular plugging by keratin (Figure 2). There was a moderately intense perivascular and periadnexal inflammatory infiltrate of mature lymphocytes with rare eosinophils within the papillary and superficial reticular dermis. There was no evidence of a viral cytopathic effect, and an immunohistochemical stain for varicella-zoster virus protein was negative. The histologic findings were suggestive of cutaneous involvement by DLE. A diagnosis of a cutaneous lupus erythematosus–like Wolf isotopic response was made, and the patient’s rash resolved with the use of triamcinolone cream 0.1% applied twice daily for 2 weeks. At 6-week follow-up, there were postinflammatory pigmentation changes at the sites of the prior rash and persistent postherpetic neuralgia. Recent antinuclear antibody screening was negative, coupled with the patient’s lack of systemic symptoms and quick resolution of rash, indicating that additional testing for systemic lupus was not warranted.

Wolf isotopic response describes the occurrence of a new skin disorder at the site of a previously healed and unrelated skin disorder. The second disease may appear within days to years after the primary disease subsides and is clearly differentiated from the isomorphic response of the Koebner phenomenon, which describes an established skin disorder appearing at a previously uninvolved anatomic site following trauma.¹ As in our case, the initial cutaneous eruption resulting in a subsequent Wolf isotopic response frequently is herpes zoster and less commonly is herpes simplex virus.² The most common reported isotopic response is a granulomatous reaction.² Rare reports of leukemic infiltration, lymphoma, lichen planus, morphea, reactive perforating collagenosis, psoriasis, discoid lupus, lichen simplex chronicus, contact dermatitis, xanthomatous changes, malignant tumors, cutaneous graft-vs-host disease, pityriasis rosea, erythema annulare centrifugum, and other infectious-based isotopic responses exist.^2-6

Our patient presented with Wolf isotopic response that histologically mimicked DLE. A PubMed search of articles indexed for MEDLINE using the terms isotopic response and lupus revealed only 3 cases of cutaneous lupus erythematosus presenting as an isotopic response in the English-language literature. One of those cases occurred in a patient with preexisting systemic lupus erythematosus, making a diagnosis of Koebner isomorphic phenomenon more appropriate than an isotopic response at the site of prior herpes zoster infection.⁷ The remaining 2 cases were clinically defined DLE lesions occurring at sites of prior infection—cutaneous leishmaniasis and herpes zoster—in patients without a prior history of cutaneous or systemic lupus erythematosus.^8,9 The latter case of DLE-like isotopic response occurring after herpes zoster infection was further complicated by local injections at the zoster site for herpes-related local pain. Injection sites are reported as a distinct nidus for Wolf isotopic response.⁹

The pathogenesis of Wolf isotopic response is unclear. Possible explanations include local interactions between persistent viral particles at prior herpes infection sites, vascular injury, neural injury, and an altered immune response.^1,5,6,10 The destruction of sensory nerve fibers by herpesviruses cause the release of neuropeptides that then modulate the local immune system and angiogenic responses.^5,6 Our patient’s immunocompromised state may have further propagated a local altered immune cell infiltrate at the site of the isotopic response. Despite its unclear etiology, Wolf isotopic response should be considered in the differential diagnosis for any patient who presents with a dermatomal eruption at the site of a prior cutaneous infection, particularly after infection with herpes zoster. Treatment with topical or intralesional corticosteroids usually suffices for inflammatory-based isotopic responses with an excellent prognosis.¹¹

We present a case of a cutaneous lupus erythematosus–like isotopic response that occurred at the site of a recent herpes zoster eruption in an immunocompromised patient without prior history of systemic or cutaneous lupus erythematosus. Clinical recognition of Wolf isotopic response is important for accurate histopathologic diagnosis and management. Continued investigation into the underlying pathogenesis should be performed to fully understand and better treat this process.

To the Editor:

Wolf isotopic response describes the development of a skin disorder at the site of another healed and unrelated skin disease. Skin disorders presenting as isotopic responses have included inflammatory, malignant, granulomatous, and infectious processes. Discoid lupus erythematosus (DLE) is a rare isotopic response. We report a cutaneous lupus erythematosus–like isotopic response that presented at the site of a recent herpes zoster infection in a liver transplant recipient.

A 74-year-old immunocompromised woman was referred to the dermatology clinic for evaluation of a rash on the right leg. She was being treated with maintenance valganciclovir due to cytomegalovirus viremia, as well as tacrolimus, azathioprine, and prednisone following liver transplantation due to autoimmune hepatitis for 8 months prior to presentation. Eighteen days prior to the current presentation, she was clinically diagnosed with herpes zoster. As the grouped vesicles from the herpes zoster resolved, she developed pink scaly papules in the same distribution as the original vesicular eruption.

Physical examination revealed numerous erythematous, 2- to 3-mm, scaly papules that coalesced into small plaques with serous crusts; they originated above the supragluteal cleft and extended rightward in the L3 and L4 dermatomes to the right knee (Figure 1). A 3-mm punch biopsy specimen was obtained from the right anterior thigh. Histologic analysis revealed interface lymphocytic inflammation with squamatization of basal keratinocytes, basement membrane thickening, and follicular plugging by keratin (Figure 2). There was a moderately intense perivascular and periadnexal inflammatory infiltrate of mature lymphocytes with rare eosinophils within the papillary and superficial reticular dermis. There was no evidence of a viral cytopathic effect, and an immunohistochemical stain for varicella-zoster virus protein was negative. The histologic findings were suggestive of cutaneous involvement by DLE. A diagnosis of a cutaneous lupus erythematosus–like Wolf isotopic response was made, and the patient’s rash resolved with the use of triamcinolone cream 0.1% applied twice daily for 2 weeks. At 6-week follow-up, there were postinflammatory pigmentation changes at the sites of the prior rash and persistent postherpetic neuralgia. Recent antinuclear antibody screening was negative, coupled with the patient’s lack of systemic symptoms and quick resolution of rash, indicating that additional testing for systemic lupus was not warranted.

Wolf isotopic response describes the occurrence of a new skin disorder at the site of a previously healed and unrelated skin disorder. The second disease may appear within days to years after the primary disease subsides and is clearly differentiated from the isomorphic response of the Koebner phenomenon, which describes an established skin disorder appearing at a previously uninvolved anatomic site following trauma.¹ As in our case, the initial cutaneous eruption resulting in a subsequent Wolf isotopic response frequently is herpes zoster and less commonly is herpes simplex virus.² The most common reported isotopic response is a granulomatous reaction.² Rare reports of leukemic infiltration, lymphoma, lichen planus, morphea, reactive perforating collagenosis, psoriasis, discoid lupus, lichen simplex chronicus, contact dermatitis, xanthomatous changes, malignant tumors, cutaneous graft-vs-host disease, pityriasis rosea, erythema annulare centrifugum, and other infectious-based isotopic responses exist.^2-6

Our patient presented with Wolf isotopic response that histologically mimicked DLE. A PubMed search of articles indexed for MEDLINE using the terms isotopic response and lupus revealed only 3 cases of cutaneous lupus erythematosus presenting as an isotopic response in the English-language literature. One of those cases occurred in a patient with preexisting systemic lupus erythematosus, making a diagnosis of Koebner isomorphic phenomenon more appropriate than an isotopic response at the site of prior herpes zoster infection.⁷ The remaining 2 cases were clinically defined DLE lesions occurring at sites of prior infection—cutaneous leishmaniasis and herpes zoster—in patients without a prior history of cutaneous or systemic lupus erythematosus.^8,9 The latter case of DLE-like isotopic response occurring after herpes zoster infection was further complicated by local injections at the zoster site for herpes-related local pain. Injection sites are reported as a distinct nidus for Wolf isotopic response.⁹

The pathogenesis of Wolf isotopic response is unclear. Possible explanations include local interactions between persistent viral particles at prior herpes infection sites, vascular injury, neural injury, and an altered immune response.^1,5,6,10 The destruction of sensory nerve fibers by herpesviruses cause the release of neuropeptides that then modulate the local immune system and angiogenic responses.^5,6 Our patient’s immunocompromised state may have further propagated a local altered immune cell infiltrate at the site of the isotopic response. Despite its unclear etiology, Wolf isotopic response should be considered in the differential diagnosis for any patient who presents with a dermatomal eruption at the site of a prior cutaneous infection, particularly after infection with herpes zoster. Treatment with topical or intralesional corticosteroids usually suffices for inflammatory-based isotopic responses with an excellent prognosis.¹¹

We present a case of a cutaneous lupus erythematosus–like isotopic response that occurred at the site of a recent herpes zoster eruption in an immunocompromised patient without prior history of systemic or cutaneous lupus erythematosus. Clinical recognition of Wolf isotopic response is important for accurate histopathologic diagnosis and management. Continued investigation into the underlying pathogenesis should be performed to fully understand and better treat this process.

To the Editor:

Wolf isotopic response describes the development of a skin disorder at the site of another healed and unrelated skin disease. Skin disorders presenting as isotopic responses have included inflammatory, malignant, granulomatous, and infectious processes. Discoid lupus erythematosus (DLE) is a rare isotopic response. We report a cutaneous lupus erythematosus–like isotopic response that presented at the site of a recent herpes zoster infection in a liver transplant recipient.

A 74-year-old immunocompromised woman was referred to the dermatology clinic for evaluation of a rash on the right leg. She was being treated with maintenance valganciclovir due to cytomegalovirus viremia, as well as tacrolimus, azathioprine, and prednisone following liver transplantation due to autoimmune hepatitis for 8 months prior to presentation. Eighteen days prior to the current presentation, she was clinically diagnosed with herpes zoster. As the grouped vesicles from the herpes zoster resolved, she developed pink scaly papules in the same distribution as the original vesicular eruption.

Physical examination revealed numerous erythematous, 2- to 3-mm, scaly papules that coalesced into small plaques with serous crusts; they originated above the supragluteal cleft and extended rightward in the L3 and L4 dermatomes to the right knee (Figure 1). A 3-mm punch biopsy specimen was obtained from the right anterior thigh. Histologic analysis revealed interface lymphocytic inflammation with squamatization of basal keratinocytes, basement membrane thickening, and follicular plugging by keratin (Figure 2). There was a moderately intense perivascular and periadnexal inflammatory infiltrate of mature lymphocytes with rare eosinophils within the papillary and superficial reticular dermis. There was no evidence of a viral cytopathic effect, and an immunohistochemical stain for varicella-zoster virus protein was negative. The histologic findings were suggestive of cutaneous involvement by DLE. A diagnosis of a cutaneous lupus erythematosus–like Wolf isotopic response was made, and the patient’s rash resolved with the use of triamcinolone cream 0.1% applied twice daily for 2 weeks. At 6-week follow-up, there were postinflammatory pigmentation changes at the sites of the prior rash and persistent postherpetic neuralgia. Recent antinuclear antibody screening was negative, coupled with the patient’s lack of systemic symptoms and quick resolution of rash, indicating that additional testing for systemic lupus was not warranted.

Wolf isotopic response describes the occurrence of a new skin disorder at the site of a previously healed and unrelated skin disorder. The second disease may appear within days to years after the primary disease subsides and is clearly differentiated from the isomorphic response of the Koebner phenomenon, which describes an established skin disorder appearing at a previously uninvolved anatomic site following trauma.¹ As in our case, the initial cutaneous eruption resulting in a subsequent Wolf isotopic response frequently is herpes zoster and less commonly is herpes simplex virus.² The most common reported isotopic response is a granulomatous reaction.² Rare reports of leukemic infiltration, lymphoma, lichen planus, morphea, reactive perforating collagenosis, psoriasis, discoid lupus, lichen simplex chronicus, contact dermatitis, xanthomatous changes, malignant tumors, cutaneous graft-vs-host disease, pityriasis rosea, erythema annulare centrifugum, and other infectious-based isotopic responses exist.^2-6

Our patient presented with Wolf isotopic response that histologically mimicked DLE. A PubMed search of articles indexed for MEDLINE using the terms isotopic response and lupus revealed only 3 cases of cutaneous lupus erythematosus presenting as an isotopic response in the English-language literature. One of those cases occurred in a patient with preexisting systemic lupus erythematosus, making a diagnosis of Koebner isomorphic phenomenon more appropriate than an isotopic response at the site of prior herpes zoster infection.⁷ The remaining 2 cases were clinically defined DLE lesions occurring at sites of prior infection—cutaneous leishmaniasis and herpes zoster—in patients without a prior history of cutaneous or systemic lupus erythematosus.^8,9 The latter case of DLE-like isotopic response occurring after herpes zoster infection was further complicated by local injections at the zoster site for herpes-related local pain. Injection sites are reported as a distinct nidus for Wolf isotopic response.⁹

The pathogenesis of Wolf isotopic response is unclear. Possible explanations include local interactions between persistent viral particles at prior herpes infection sites, vascular injury, neural injury, and an altered immune response.^1,5,6,10 The destruction of sensory nerve fibers by herpesviruses cause the release of neuropeptides that then modulate the local immune system and angiogenic responses.^5,6 Our patient’s immunocompromised state may have further propagated a local altered immune cell infiltrate at the site of the isotopic response. Despite its unclear etiology, Wolf isotopic response should be considered in the differential diagnosis for any patient who presents with a dermatomal eruption at the site of a prior cutaneous infection, particularly after infection with herpes zoster. Treatment with topical or intralesional corticosteroids usually suffices for inflammatory-based isotopic responses with an excellent prognosis.¹¹

We present a case of a cutaneous lupus erythematosus–like isotopic response that occurred at the site of a recent herpes zoster eruption in an immunocompromised patient without prior history of systemic or cutaneous lupus erythematosus. Clinical recognition of Wolf isotopic response is important for accurate histopathologic diagnosis and management. Continued investigation into the underlying pathogenesis should be performed to fully understand and better treat this process.

Acute hemorrhagic edema of infancy (AHEI) is an uncommon leukocytoclastic vasculitis affecting children aged 6 to 24 months; Henoch-Schönlein purpura (HSP) is the most common misdiagnosis. The 2 entities should be differentiated, as HSP may have renal and gastrointestinal (GI) comorbidities that need serial follow-up, whereas AHEI follows a benign course without systemic sequelae. Patient history and physical examination are the most important factors in differentiating the 2 diseases; histopathologic and direct immunofluorescence (DIF) analyses may lend further diagnostic confidence.

We report the case of a 10-month-old previously healthy boy who presented with acute rash, edema, and low-grade fever in the setting of recent diarrhea. We differentiate between AHEI and HSP to help prevent misdiagnosis by health care providers.

Case Report

A 10-month-old previously healthy boy presented to the emergency department (ED) for evaluation of a rash and swelling of 4 days’ duration. He had nonbloody diarrhea 1 week prior; soon after, he developed bilateral lower leg edema and rash. On evaluation in a different ED, he had a low-grade fever (rectal temperature, 38.0°C) but normal blood work, including complete blood cell count, basic metabolic panel, and coagulation studies. The patient was discharged to outpatient follow-up with his pediatrician who reported normal urinalysis.

Due to progression of the rash, the patient presented to our ED 3 days after his initial ED assessment. Dermatology was consulted. At the time of presentation, he was afebrile but with GI upset and fussiness. His parents denied additional symptoms or blood in urine or stool. Physical examination revealed a nontoxic-appearing infant with scattered palpable, annular, purpuric papules coalescing into plaques on both legs and feet (Figure 1), with sparse petechiae noted on the lower abdomen. The cheeks had scattered purpuric papules and plaques bilaterally, a few with a small central crust (Figure 2), and the right superior helix had a faint purpuric macule. The hands had a few pink edematous coalescing papules.

Histopathologic analyses with hematoxylin and eosin staining (Figure 3) and DIF (Figure 4) were performed from within a representative purpuric plaque on the right hip. Direct immunofluorescence was performed to evaluate for an IgA vasculitis versus an alternative type of vasculitis. The hematoxylin and eosin–stained specimen demonstrated a dermal perivascular infiltrate involving superficial and deep vessels with neutrophils, karyorrhexis, and erythrocyte extravasation. The endothelium was intact, with a mild suggestion of fibrinoid change of the blood vessel walls. Direct immunofluorescence revealed granular deposition of IgA, C3, and fibrinogen in multiple dermal blood vessels. Combined, the specimens were interpreted as evolving IgA-associated leukocytoclastic vasculitis.

The case was reviewed with our 2 department pediatric dermatologists; a diagnosis of AHEI was made based on the clinical and supportive histopathological presentations. The patient’s parents chose active treatment with a 2-week taper of oral prednisone because of the patient’s discomfort with edema. No GI or adverse renal sequelae, including findings on urinalysis, were reported at 1-month hospital follow-up with dermatology and pediatrics.

Comment

Incidence and Clinical Characteristics
Acute hemorrhagic edema of infancy is an uncommon leukocytoclastic vasculitis first described in the United States by Snow¹ in 1913. Other names for the disorder include acute hemorrhagic edema of young children, cockade purpura and edema, Finkelstein disease, and Seidlmayer disease.² Boys are affected more often than girls, with most children presenting at 6 to 24 months of age. Most affected children experience a prodrome of simple respiratory tract illness (most common), diarrhea (as in our case), or urinary tract infection.² The exact pathophysiology behind AHEI is unknown, but it is thought to be an immune complex–mediated disease evidenced by the fact that infection, use of medication, or immunization precedes most cases.^3,4

Diagnosis
Acute hemorrhagic edema of infancy is diagnosed clinically, with or without the support of skin biopsy. It should be differentiated from HSP because of renal and GI sequelae that HSP portends compared to the benign course of AHEI.² Notably, some health care providers consider AHEI a benign variant of HSP.^2,3

Characteristically, AHEI patients are nontoxic-appearing infants with a low-grade fever who develop relatively large (1–5 cm) targetoid purpuric lesions and indurated nonpitting edema of the extremities.^2,5 Purpura in AHEI frequently occurs on the face, ears, and upper and lower extremities, whereas purpura in HSP most commonly presents on the buttocks and extensor legs with sparing of the face. Henoch-Schönlein purpura most often affects children aged 3 to 6 years compared to AHEI’s younger demographic (age <2 years).^4,5 Clinically, HSP presents with palpable purpura and 1 or more of the following features: diffuse abdominal pain, arthritis/arthralgia, renal involvement, and skin or renal biopsy showing predominant IgA deposition.^2,6

Both AHEI and HSP show leukocytoclastic vasculitis on histopathology.^2-4,6,7 Positive perivascular IgA staining on DIF is strongly associated with HSP, but nearly one-quarter of AHEI cases also show this deposition pattern^2,4,7; therefore, DIF alone cannot exclude a diagnosis of AHEI.

Differential Diagnosis
Alternative diagnoses to consider with AHEI include drug-induced vasculitis, erythema multiforme, HSP, Kawasaki disease, meningococcemia, nonaccidental skin bruising, Rocky Mountain spotted fever, septic vasculitis, and urticarial vasculitis (Table).^2-4,6-8

Treatment
Acute hemorrhagic edema of infancy is self-limited, with only rare reports of extracutaneous involvement. Supportive treatment is indicated because spontaneous recovery without sequelae is expected within 21 days.^2,3,6 If edema is symptomatic, as was the case with our patient, corticosteroids may shorten the disease course.³

Conclusion

Our case highlights the need to combine clinical history, physical examination, and histopathologic analysis to differentiate between AHEI and HSP, which is important for 2 reasons: (1) it helps with the decision to undertake active or observational treatment, and (2) it helps the clinician counsel the patient and guardians regarding potential associated renal and GI risks.

Acute hemorrhagic edema of infancy (AHEI) is an uncommon leukocytoclastic vasculitis affecting children aged 6 to 24 months; Henoch-Schönlein purpura (HSP) is the most common misdiagnosis. The 2 entities should be differentiated, as HSP may have renal and gastrointestinal (GI) comorbidities that need serial follow-up, whereas AHEI follows a benign course without systemic sequelae. Patient history and physical examination are the most important factors in differentiating the 2 diseases; histopathologic and direct immunofluorescence (DIF) analyses may lend further diagnostic confidence.

We report the case of a 10-month-old previously healthy boy who presented with acute rash, edema, and low-grade fever in the setting of recent diarrhea. We differentiate between AHEI and HSP to help prevent misdiagnosis by health care providers.

Case Report

A 10-month-old previously healthy boy presented to the emergency department (ED) for evaluation of a rash and swelling of 4 days’ duration. He had nonbloody diarrhea 1 week prior; soon after, he developed bilateral lower leg edema and rash. On evaluation in a different ED, he had a low-grade fever (rectal temperature, 38.0°C) but normal blood work, including complete blood cell count, basic metabolic panel, and coagulation studies. The patient was discharged to outpatient follow-up with his pediatrician who reported normal urinalysis.

Due to progression of the rash, the patient presented to our ED 3 days after his initial ED assessment. Dermatology was consulted. At the time of presentation, he was afebrile but with GI upset and fussiness. His parents denied additional symptoms or blood in urine or stool. Physical examination revealed a nontoxic-appearing infant with scattered palpable, annular, purpuric papules coalescing into plaques on both legs and feet (Figure 1), with sparse petechiae noted on the lower abdomen. The cheeks had scattered purpuric papules and plaques bilaterally, a few with a small central crust (Figure 2), and the right superior helix had a faint purpuric macule. The hands had a few pink edematous coalescing papules.

Histopathologic analyses with hematoxylin and eosin staining (Figure 3) and DIF (Figure 4) were performed from within a representative purpuric plaque on the right hip. Direct immunofluorescence was performed to evaluate for an IgA vasculitis versus an alternative type of vasculitis. The hematoxylin and eosin–stained specimen demonstrated a dermal perivascular infiltrate involving superficial and deep vessels with neutrophils, karyorrhexis, and erythrocyte extravasation. The endothelium was intact, with a mild suggestion of fibrinoid change of the blood vessel walls. Direct immunofluorescence revealed granular deposition of IgA, C3, and fibrinogen in multiple dermal blood vessels. Combined, the specimens were interpreted as evolving IgA-associated leukocytoclastic vasculitis.

The case was reviewed with our 2 department pediatric dermatologists; a diagnosis of AHEI was made based on the clinical and supportive histopathological presentations. The patient’s parents chose active treatment with a 2-week taper of oral prednisone because of the patient’s discomfort with edema. No GI or adverse renal sequelae, including findings on urinalysis, were reported at 1-month hospital follow-up with dermatology and pediatrics.

Comment

Incidence and Clinical Characteristics
Acute hemorrhagic edema of infancy is an uncommon leukocytoclastic vasculitis first described in the United States by Snow¹ in 1913. Other names for the disorder include acute hemorrhagic edema of young children, cockade purpura and edema, Finkelstein disease, and Seidlmayer disease.² Boys are affected more often than girls, with most children presenting at 6 to 24 months of age. Most affected children experience a prodrome of simple respiratory tract illness (most common), diarrhea (as in our case), or urinary tract infection.² The exact pathophysiology behind AHEI is unknown, but it is thought to be an immune complex–mediated disease evidenced by the fact that infection, use of medication, or immunization precedes most cases.^3,4

Diagnosis
Acute hemorrhagic edema of infancy is diagnosed clinically, with or without the support of skin biopsy. It should be differentiated from HSP because of renal and GI sequelae that HSP portends compared to the benign course of AHEI.² Notably, some health care providers consider AHEI a benign variant of HSP.^2,3

Characteristically, AHEI patients are nontoxic-appearing infants with a low-grade fever who develop relatively large (1–5 cm) targetoid purpuric lesions and indurated nonpitting edema of the extremities.^2,5 Purpura in AHEI frequently occurs on the face, ears, and upper and lower extremities, whereas purpura in HSP most commonly presents on the buttocks and extensor legs with sparing of the face. Henoch-Schönlein purpura most often affects children aged 3 to 6 years compared to AHEI’s younger demographic (age <2 years).^4,5 Clinically, HSP presents with palpable purpura and 1 or more of the following features: diffuse abdominal pain, arthritis/arthralgia, renal involvement, and skin or renal biopsy showing predominant IgA deposition.^2,6

Both AHEI and HSP show leukocytoclastic vasculitis on histopathology.^2-4,6,7 Positive perivascular IgA staining on DIF is strongly associated with HSP, but nearly one-quarter of AHEI cases also show this deposition pattern^2,4,7; therefore, DIF alone cannot exclude a diagnosis of AHEI.

Differential Diagnosis
Alternative diagnoses to consider with AHEI include drug-induced vasculitis, erythema multiforme, HSP, Kawasaki disease, meningococcemia, nonaccidental skin bruising, Rocky Mountain spotted fever, septic vasculitis, and urticarial vasculitis (Table).^2-4,6-8

Treatment
Acute hemorrhagic edema of infancy is self-limited, with only rare reports of extracutaneous involvement. Supportive treatment is indicated because spontaneous recovery without sequelae is expected within 21 days.^2,3,6 If edema is symptomatic, as was the case with our patient, corticosteroids may shorten the disease course.³

Conclusion

Our case highlights the need to combine clinical history, physical examination, and histopathologic analysis to differentiate between AHEI and HSP, which is important for 2 reasons: (1) it helps with the decision to undertake active or observational treatment, and (2) it helps the clinician counsel the patient and guardians regarding potential associated renal and GI risks.

Acute hemorrhagic edema of infancy (AHEI) is an uncommon leukocytoclastic vasculitis affecting children aged 6 to 24 months; Henoch-Schönlein purpura (HSP) is the most common misdiagnosis. The 2 entities should be differentiated, as HSP may have renal and gastrointestinal (GI) comorbidities that need serial follow-up, whereas AHEI follows a benign course without systemic sequelae. Patient history and physical examination are the most important factors in differentiating the 2 diseases; histopathologic and direct immunofluorescence (DIF) analyses may lend further diagnostic confidence.

We report the case of a 10-month-old previously healthy boy who presented with acute rash, edema, and low-grade fever in the setting of recent diarrhea. We differentiate between AHEI and HSP to help prevent misdiagnosis by health care providers.

Case Report

A 10-month-old previously healthy boy presented to the emergency department (ED) for evaluation of a rash and swelling of 4 days’ duration. He had nonbloody diarrhea 1 week prior; soon after, he developed bilateral lower leg edema and rash. On evaluation in a different ED, he had a low-grade fever (rectal temperature, 38.0°C) but normal blood work, including complete blood cell count, basic metabolic panel, and coagulation studies. The patient was discharged to outpatient follow-up with his pediatrician who reported normal urinalysis.

Due to progression of the rash, the patient presented to our ED 3 days after his initial ED assessment. Dermatology was consulted. At the time of presentation, he was afebrile but with GI upset and fussiness. His parents denied additional symptoms or blood in urine or stool. Physical examination revealed a nontoxic-appearing infant with scattered palpable, annular, purpuric papules coalescing into plaques on both legs and feet (Figure 1), with sparse petechiae noted on the lower abdomen. The cheeks had scattered purpuric papules and plaques bilaterally, a few with a small central crust (Figure 2), and the right superior helix had a faint purpuric macule. The hands had a few pink edematous coalescing papules.

Histopathologic analyses with hematoxylin and eosin staining (Figure 3) and DIF (Figure 4) were performed from within a representative purpuric plaque on the right hip. Direct immunofluorescence was performed to evaluate for an IgA vasculitis versus an alternative type of vasculitis. The hematoxylin and eosin–stained specimen demonstrated a dermal perivascular infiltrate involving superficial and deep vessels with neutrophils, karyorrhexis, and erythrocyte extravasation. The endothelium was intact, with a mild suggestion of fibrinoid change of the blood vessel walls. Direct immunofluorescence revealed granular deposition of IgA, C3, and fibrinogen in multiple dermal blood vessels. Combined, the specimens were interpreted as evolving IgA-associated leukocytoclastic vasculitis.

The case was reviewed with our 2 department pediatric dermatologists; a diagnosis of AHEI was made based on the clinical and supportive histopathological presentations. The patient’s parents chose active treatment with a 2-week taper of oral prednisone because of the patient’s discomfort with edema. No GI or adverse renal sequelae, including findings on urinalysis, were reported at 1-month hospital follow-up with dermatology and pediatrics.

Comment

Incidence and Clinical Characteristics
Acute hemorrhagic edema of infancy is an uncommon leukocytoclastic vasculitis first described in the United States by Snow¹ in 1913. Other names for the disorder include acute hemorrhagic edema of young children, cockade purpura and edema, Finkelstein disease, and Seidlmayer disease.² Boys are affected more often than girls, with most children presenting at 6 to 24 months of age. Most affected children experience a prodrome of simple respiratory tract illness (most common), diarrhea (as in our case), or urinary tract infection.² The exact pathophysiology behind AHEI is unknown, but it is thought to be an immune complex–mediated disease evidenced by the fact that infection, use of medication, or immunization precedes most cases.^3,4

Diagnosis
Acute hemorrhagic edema of infancy is diagnosed clinically, with or without the support of skin biopsy. It should be differentiated from HSP because of renal and GI sequelae that HSP portends compared to the benign course of AHEI.² Notably, some health care providers consider AHEI a benign variant of HSP.^2,3

Characteristically, AHEI patients are nontoxic-appearing infants with a low-grade fever who develop relatively large (1–5 cm) targetoid purpuric lesions and indurated nonpitting edema of the extremities.^2,5 Purpura in AHEI frequently occurs on the face, ears, and upper and lower extremities, whereas purpura in HSP most commonly presents on the buttocks and extensor legs with sparing of the face. Henoch-Schönlein purpura most often affects children aged 3 to 6 years compared to AHEI’s younger demographic (age <2 years).^4,5 Clinically, HSP presents with palpable purpura and 1 or more of the following features: diffuse abdominal pain, arthritis/arthralgia, renal involvement, and skin or renal biopsy showing predominant IgA deposition.^2,6

Both AHEI and HSP show leukocytoclastic vasculitis on histopathology.^2-4,6,7 Positive perivascular IgA staining on DIF is strongly associated with HSP, but nearly one-quarter of AHEI cases also show this deposition pattern^2,4,7; therefore, DIF alone cannot exclude a diagnosis of AHEI.

Differential Diagnosis
Alternative diagnoses to consider with AHEI include drug-induced vasculitis, erythema multiforme, HSP, Kawasaki disease, meningococcemia, nonaccidental skin bruising, Rocky Mountain spotted fever, septic vasculitis, and urticarial vasculitis (Table).^2-4,6-8

Treatment
Acute hemorrhagic edema of infancy is self-limited, with only rare reports of extracutaneous involvement. Supportive treatment is indicated because spontaneous recovery without sequelae is expected within 21 days.^2,3,6 If edema is symptomatic, as was the case with our patient, corticosteroids may shorten the disease course.³

Conclusion

Our case highlights the need to combine clinical history, physical examination, and histopathologic analysis to differentiate between AHEI and HSP, which is important for 2 reasons: (1) it helps with the decision to undertake active or observational treatment, and (2) it helps the clinician counsel the patient and guardians regarding potential associated renal and GI risks.

Clothes moths are common pests found inside buildings such as homes, stores, and museums. The most common species of importance include the webbing clothes moth (Tineola bisselliella)(Figure) and the casemaking clothes moth (Tineola pellionella). Both species target textiles such as wool, rugs, feathers, felts, hair, furs, and even grains.^1,2 They avoid synthetics and plant materials such as cottons.¹

Characteristics

Adult clothes moths extend 7 to 8 mm and are a golden (T bisselliella) to brown (T pellionella) color with fringed wings and a tuft on their heads.^1,3 Adults do not eat; females die within a few days of laying eggs, while males live approximately 1 month. Once laid, eggs hatch within 4 to 10 days.^1,3 The larvae (caterpillars) incur damage to clothes and other household goods. Fully mature larvae are 12- to 13-mm long, and the Tineola species have white- to cream-colored bodies with brown heads. The webbing clothes moth larva lacks ocelli (eyes), while the casemaking moth larva has a singular ocellus.¹

Transmission

An infestation is evidenced by woolen items that have furrows or holes in them. Pheromone traps also can expose an active infestation.³ The webbing moth larvae can be found beneath a self-spun silken mat on the food source that offers the insect protection and camouflage while it eats; the mat collects frass (feces) and clothes particles.^1,3,4 The casemaking moth larvae drag around a portable silken bag that takes on the color of the fabric being eaten and serves as a refuge when disturbed.^1,3,4 Both adult and larval stages prefer low light conditions. The total time of development from caterpillar to adult varies depending on the temperature and humidity of the environment, but most clothes moths complete their life cycle within 1 to 3 months.¹

Management of an Infestation

Multiple infestation treatment options exist should a patient present with a clothes moth infestation. Infested clothing articles or small blankets and rugs can be dry-cleaned or laundered. Any items not in use should be laundered before being sealed in airtight storage containers. Mothball vapor at appropriate concentrations is lethal to the moths, and when possible, clothing should be stored with mothballs or flakes at the concentration recommended by the manufacturer.⁴ Individuals should avoid application of household insecticides to clothing or bedding, which may be poisonous to people.^1,4 Freezing, heating, and dry ice fumigation techniques also can be used to treat infested products.³ Cedarwood usually is insufficient to deter an infestation, as the oil vapor rarely reaches an effective concentration to repel or harm the insects.^3,4 Strict housekeeping with attention to vacuuming carpets, baseboards, closets, and laundering all linens and furniture covers can further reduce an infestation.⁴ Clothes items can be set in the sunlight and brushed to help loosen the pests, as they dislike direct light and may fall from the garments.³ Dust insecticides also can be used per the manufacturer label to treat crevices and baseboards in an active area of infestation that may otherwise be difficult to clean.³ If an extensive infestation exists or larger items are infested, then a professional pest control agency should be employed for proper eradication.

Conclusion

Understanding the life cycle and basic biology of clothes moths and other common household pests will help the clinician identify an infestation and counsel patients if an insect is a true ectoparasite. Clothes moth larvae are not parasites but can be found on clothing and can be confused with myiasis or true parasites.

Clothes moths are common pests found inside buildings such as homes, stores, and museums. The most common species of importance include the webbing clothes moth (Tineola bisselliella)(Figure) and the casemaking clothes moth (Tineola pellionella). Both species target textiles such as wool, rugs, feathers, felts, hair, furs, and even grains.^1,2 They avoid synthetics and plant materials such as cottons.¹

Characteristics

Adult clothes moths extend 7 to 8 mm and are a golden (T bisselliella) to brown (T pellionella) color with fringed wings and a tuft on their heads.^1,3 Adults do not eat; females die within a few days of laying eggs, while males live approximately 1 month. Once laid, eggs hatch within 4 to 10 days.^1,3 The larvae (caterpillars) incur damage to clothes and other household goods. Fully mature larvae are 12- to 13-mm long, and the Tineola species have white- to cream-colored bodies with brown heads. The webbing clothes moth larva lacks ocelli (eyes), while the casemaking moth larva has a singular ocellus.¹

Transmission

An infestation is evidenced by woolen items that have furrows or holes in them. Pheromone traps also can expose an active infestation.³ The webbing moth larvae can be found beneath a self-spun silken mat on the food source that offers the insect protection and camouflage while it eats; the mat collects frass (feces) and clothes particles.^1,3,4 The casemaking moth larvae drag around a portable silken bag that takes on the color of the fabric being eaten and serves as a refuge when disturbed.^1,3,4 Both adult and larval stages prefer low light conditions. The total time of development from caterpillar to adult varies depending on the temperature and humidity of the environment, but most clothes moths complete their life cycle within 1 to 3 months.¹

Management of an Infestation

Multiple infestation treatment options exist should a patient present with a clothes moth infestation. Infested clothing articles or small blankets and rugs can be dry-cleaned or laundered. Any items not in use should be laundered before being sealed in airtight storage containers. Mothball vapor at appropriate concentrations is lethal to the moths, and when possible, clothing should be stored with mothballs or flakes at the concentration recommended by the manufacturer.⁴ Individuals should avoid application of household insecticides to clothing or bedding, which may be poisonous to people.^1,4 Freezing, heating, and dry ice fumigation techniques also can be used to treat infested products.³ Cedarwood usually is insufficient to deter an infestation, as the oil vapor rarely reaches an effective concentration to repel or harm the insects.^3,4 Strict housekeeping with attention to vacuuming carpets, baseboards, closets, and laundering all linens and furniture covers can further reduce an infestation.⁴ Clothes items can be set in the sunlight and brushed to help loosen the pests, as they dislike direct light and may fall from the garments.³ Dust insecticides also can be used per the manufacturer label to treat crevices and baseboards in an active area of infestation that may otherwise be difficult to clean.³ If an extensive infestation exists or larger items are infested, then a professional pest control agency should be employed for proper eradication.

Conclusion

Understanding the life cycle and basic biology of clothes moths and other common household pests will help the clinician identify an infestation and counsel patients if an insect is a true ectoparasite. Clothes moth larvae are not parasites but can be found on clothing and can be confused with myiasis or true parasites.

Clothes moths are common pests found inside buildings such as homes, stores, and museums. The most common species of importance include the webbing clothes moth (Tineola bisselliella)(Figure) and the casemaking clothes moth (Tineola pellionella). Both species target textiles such as wool, rugs, feathers, felts, hair, furs, and even grains.^1,2 They avoid synthetics and plant materials such as cottons.¹

Characteristics

Adult clothes moths extend 7 to 8 mm and are a golden (T bisselliella) to brown (T pellionella) color with fringed wings and a tuft on their heads.^1,3 Adults do not eat; females die within a few days of laying eggs, while males live approximately 1 month. Once laid, eggs hatch within 4 to 10 days.^1,3 The larvae (caterpillars) incur damage to clothes and other household goods. Fully mature larvae are 12- to 13-mm long, and the Tineola species have white- to cream-colored bodies with brown heads. The webbing clothes moth larva lacks ocelli (eyes), while the casemaking moth larva has a singular ocellus.¹

Transmission

An infestation is evidenced by woolen items that have furrows or holes in them. Pheromone traps also can expose an active infestation.³ The webbing moth larvae can be found beneath a self-spun silken mat on the food source that offers the insect protection and camouflage while it eats; the mat collects frass (feces) and clothes particles.^1,3,4 The casemaking moth larvae drag around a portable silken bag that takes on the color of the fabric being eaten and serves as a refuge when disturbed.^1,3,4 Both adult and larval stages prefer low light conditions. The total time of development from caterpillar to adult varies depending on the temperature and humidity of the environment, but most clothes moths complete their life cycle within 1 to 3 months.¹

Management of an Infestation

Multiple infestation treatment options exist should a patient present with a clothes moth infestation. Infested clothing articles or small blankets and rugs can be dry-cleaned or laundered. Any items not in use should be laundered before being sealed in airtight storage containers. Mothball vapor at appropriate concentrations is lethal to the moths, and when possible, clothing should be stored with mothballs or flakes at the concentration recommended by the manufacturer.⁴ Individuals should avoid application of household insecticides to clothing or bedding, which may be poisonous to people.^1,4 Freezing, heating, and dry ice fumigation techniques also can be used to treat infested products.³ Cedarwood usually is insufficient to deter an infestation, as the oil vapor rarely reaches an effective concentration to repel or harm the insects.^3,4 Strict housekeeping with attention to vacuuming carpets, baseboards, closets, and laundering all linens and furniture covers can further reduce an infestation.⁴ Clothes items can be set in the sunlight and brushed to help loosen the pests, as they dislike direct light and may fall from the garments.³ Dust insecticides also can be used per the manufacturer label to treat crevices and baseboards in an active area of infestation that may otherwise be difficult to clean.³ If an extensive infestation exists or larger items are infested, then a professional pest control agency should be employed for proper eradication.

Conclusion

Understanding the life cycle and basic biology of clothes moths and other common household pests will help the clinician identify an infestation and counsel patients if an insect is a true ectoparasite. Clothes moth larvae are not parasites but can be found on clothing and can be confused with myiasis or true parasites.