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What’s Eating You? Ant-Induced Alopecia (Pheidole)
Case Report
An 18-year-old Iranian man presented to the dermatology clinic with hair loss of 1 night’s duration. He denied pruritus, pain, discharge, or flaking. The patient had no notable personal, family, or surgical history and was not currently taking any medications. He denied recent travel. The patient reported that he found hair on his pillow upon waking up in the morning prior to coming to the clinic. On physical examination, 2 ants (Figure 1) were found on the scalp and alopecia with a vertical linear distribution was noted (Figure 2). Hairs of various lengths were found on the scalp within the distribution of the alopecia. No excoriations, crusting, seborrhea, or other areas of hair loss were detected. Wood lamp examination was negative. Based on these findings, which were concordant with similar findings from prior reports,1-4 a diagnosis of ant-induced alopecia was made. Hair regrowth was noted within 1 week with full appearance of normal-length hair within 2.5 weeks.
Comment
Ant-induced alopecia is a form of localized hair loss caused by the Pheidole genus, the second largest genus of ants in the world.5 These ants can be found worldwide, but most cases of ant-induced alopecia have been from Iran, with at least 1 reported case from Turkey.1-4,6 An early case series of ant-induced alopecia was reported in 1999,6 but the causative species was not described at that time.
The majority of reported cases of ant-induced alopecia are attributed to the barber ant (Pheidole pallidula). This type of alopecia is caused by worker ants within the species hierarchy.1,4,6 The P pallidula worker ants are dimorphic and are classified as major and minor workers.7 Major workers have body lengths ranging up to 6 mm, whereas minor workers have body lengths ranging up to 4 mm. Major workers have larger heads and mandibles than minor workers and also have up to 2 pairs of denticles on the cranium.5 The minor workers are foragers and mainly collect food, whereas the major workers defend the nest and store food.8 These ants have widespread habitats with the ability to live in indoor and outdoor environments.
The presentation of hair loss caused by these ants is acute. Hair loss usually is confined to one specific area. Some patients may report pruritus or may present with erythematous lesions from ant stings or manual scratching.5 None of these signs or symptoms were seen in our patient. Some investigators have suggested that the barber ant is attracted to the hair of individuals with seborrheic dermatitis,1 but our patient had no medical history of seborrheic dermatitis. Most likely, ants are attracted to excess sebum on the scalp in select individuals in their search for food and cause localized hair destruction.
Localized hair loss, as depicted in our case, should warrant a thorough evaluation for alopecia areata, trichotillomania, and tinea capitis.9 Alopecia areata should be considered in individuals with multiple focal patches of hair loss that have a positive hair pull test from peripheral sites of active lesions. Tinea capitis usually has localized sites of hair loss with underlying scaling, crusting, pruritus, erythema, and discharge from lesions, with positive potassium hydroxide preparations or fungal cultures. Trichotillomania typically presents with a spared peripheral fringe of hair. Remaining hairs may be thick and hyperpigmented as a response to repeated pulling, and biopsy often demonstrates fracture or degeneration of the hair shaft. A psychiatric evaluation may be warranted in cases of trichotillomania. Other cases of arthropod-induced hair loss include tick bite alopecia10,11 and hair loss induced by numerous honeybee stings,12 and these diagnoses should be suspected in patients with a history of ants on their pillow or in those from endemic areas.
No specific treatment is indicated in cases of ant-induced alopecia because hair usually regrows to its normal length without intervention.
- Shamsadini S. Localized scalp hair shedding caused by Pheidole ants and overview of similar case reports. Dermatol Online J. 2003;9:12.
- Aghaei S, Sodaifi M. Circumscribed scalp hair loss following multiple hair-cutter ant invasion. Dermatol Online J. 2004;10:14.
- Mortazavi M, Mansouri P. Ant-induced alopecia: report of 2 cases and review of the literature. Dermatol Online J. 2004;10:19.
- Kapdağli S, Seçkin D, Baba M, et al. Localized hair breakage caused by ants. Pediatr Dermatol. 2006;23:519-520.
- Ogata K. Toxonomy and biology of the genus Pheidole of Japan. Nature and Insects. 1981;16:17-22.
- Radmanesh M, Mousavipour M. Alopecia induced by ants. Trans R Soc Trop Med Hyg. 1999;93:427.
- Hölldobler B, Wilson EO. The Ants. Cambridge, MA: Harvard University Press; 1990.
- Wilson EO. Pheidole in the New World: A Dominant Hyperdiverse Ant Genus. Cambridge MA: Harvard University Press; 2003.
- Veraldi S, Lunardon L, Francia C, et al. Alopecia caused by the “barber ant” Pheidole pallidula. Int J Dermatol. 2008;47:1329-1330.
- Marshall J. Alopecia after tick bite. S Afr Med J. 1966;40: 555-556.
- Heyl T. Tick bite alopecia. Clin Exp Dermatol. 1982;7: 537-542.
- Sharma AK, Sharma RC, Sharma NL. Diffuse hair loss following multiple honeybee stings. Dermatology. 1997;195:305.
Case Report
An 18-year-old Iranian man presented to the dermatology clinic with hair loss of 1 night’s duration. He denied pruritus, pain, discharge, or flaking. The patient had no notable personal, family, or surgical history and was not currently taking any medications. He denied recent travel. The patient reported that he found hair on his pillow upon waking up in the morning prior to coming to the clinic. On physical examination, 2 ants (Figure 1) were found on the scalp and alopecia with a vertical linear distribution was noted (Figure 2). Hairs of various lengths were found on the scalp within the distribution of the alopecia. No excoriations, crusting, seborrhea, or other areas of hair loss were detected. Wood lamp examination was negative. Based on these findings, which were concordant with similar findings from prior reports,1-4 a diagnosis of ant-induced alopecia was made. Hair regrowth was noted within 1 week with full appearance of normal-length hair within 2.5 weeks.
Comment
Ant-induced alopecia is a form of localized hair loss caused by the Pheidole genus, the second largest genus of ants in the world.5 These ants can be found worldwide, but most cases of ant-induced alopecia have been from Iran, with at least 1 reported case from Turkey.1-4,6 An early case series of ant-induced alopecia was reported in 1999,6 but the causative species was not described at that time.
The majority of reported cases of ant-induced alopecia are attributed to the barber ant (Pheidole pallidula). This type of alopecia is caused by worker ants within the species hierarchy.1,4,6 The P pallidula worker ants are dimorphic and are classified as major and minor workers.7 Major workers have body lengths ranging up to 6 mm, whereas minor workers have body lengths ranging up to 4 mm. Major workers have larger heads and mandibles than minor workers and also have up to 2 pairs of denticles on the cranium.5 The minor workers are foragers and mainly collect food, whereas the major workers defend the nest and store food.8 These ants have widespread habitats with the ability to live in indoor and outdoor environments.
The presentation of hair loss caused by these ants is acute. Hair loss usually is confined to one specific area. Some patients may report pruritus or may present with erythematous lesions from ant stings or manual scratching.5 None of these signs or symptoms were seen in our patient. Some investigators have suggested that the barber ant is attracted to the hair of individuals with seborrheic dermatitis,1 but our patient had no medical history of seborrheic dermatitis. Most likely, ants are attracted to excess sebum on the scalp in select individuals in their search for food and cause localized hair destruction.
Localized hair loss, as depicted in our case, should warrant a thorough evaluation for alopecia areata, trichotillomania, and tinea capitis.9 Alopecia areata should be considered in individuals with multiple focal patches of hair loss that have a positive hair pull test from peripheral sites of active lesions. Tinea capitis usually has localized sites of hair loss with underlying scaling, crusting, pruritus, erythema, and discharge from lesions, with positive potassium hydroxide preparations or fungal cultures. Trichotillomania typically presents with a spared peripheral fringe of hair. Remaining hairs may be thick and hyperpigmented as a response to repeated pulling, and biopsy often demonstrates fracture or degeneration of the hair shaft. A psychiatric evaluation may be warranted in cases of trichotillomania. Other cases of arthropod-induced hair loss include tick bite alopecia10,11 and hair loss induced by numerous honeybee stings,12 and these diagnoses should be suspected in patients with a history of ants on their pillow or in those from endemic areas.
No specific treatment is indicated in cases of ant-induced alopecia because hair usually regrows to its normal length without intervention.
Case Report
An 18-year-old Iranian man presented to the dermatology clinic with hair loss of 1 night’s duration. He denied pruritus, pain, discharge, or flaking. The patient had no notable personal, family, or surgical history and was not currently taking any medications. He denied recent travel. The patient reported that he found hair on his pillow upon waking up in the morning prior to coming to the clinic. On physical examination, 2 ants (Figure 1) were found on the scalp and alopecia with a vertical linear distribution was noted (Figure 2). Hairs of various lengths were found on the scalp within the distribution of the alopecia. No excoriations, crusting, seborrhea, or other areas of hair loss were detected. Wood lamp examination was negative. Based on these findings, which were concordant with similar findings from prior reports,1-4 a diagnosis of ant-induced alopecia was made. Hair regrowth was noted within 1 week with full appearance of normal-length hair within 2.5 weeks.
Comment
Ant-induced alopecia is a form of localized hair loss caused by the Pheidole genus, the second largest genus of ants in the world.5 These ants can be found worldwide, but most cases of ant-induced alopecia have been from Iran, with at least 1 reported case from Turkey.1-4,6 An early case series of ant-induced alopecia was reported in 1999,6 but the causative species was not described at that time.
The majority of reported cases of ant-induced alopecia are attributed to the barber ant (Pheidole pallidula). This type of alopecia is caused by worker ants within the species hierarchy.1,4,6 The P pallidula worker ants are dimorphic and are classified as major and minor workers.7 Major workers have body lengths ranging up to 6 mm, whereas minor workers have body lengths ranging up to 4 mm. Major workers have larger heads and mandibles than minor workers and also have up to 2 pairs of denticles on the cranium.5 The minor workers are foragers and mainly collect food, whereas the major workers defend the nest and store food.8 These ants have widespread habitats with the ability to live in indoor and outdoor environments.
The presentation of hair loss caused by these ants is acute. Hair loss usually is confined to one specific area. Some patients may report pruritus or may present with erythematous lesions from ant stings or manual scratching.5 None of these signs or symptoms were seen in our patient. Some investigators have suggested that the barber ant is attracted to the hair of individuals with seborrheic dermatitis,1 but our patient had no medical history of seborrheic dermatitis. Most likely, ants are attracted to excess sebum on the scalp in select individuals in their search for food and cause localized hair destruction.
Localized hair loss, as depicted in our case, should warrant a thorough evaluation for alopecia areata, trichotillomania, and tinea capitis.9 Alopecia areata should be considered in individuals with multiple focal patches of hair loss that have a positive hair pull test from peripheral sites of active lesions. Tinea capitis usually has localized sites of hair loss with underlying scaling, crusting, pruritus, erythema, and discharge from lesions, with positive potassium hydroxide preparations or fungal cultures. Trichotillomania typically presents with a spared peripheral fringe of hair. Remaining hairs may be thick and hyperpigmented as a response to repeated pulling, and biopsy often demonstrates fracture or degeneration of the hair shaft. A psychiatric evaluation may be warranted in cases of trichotillomania. Other cases of arthropod-induced hair loss include tick bite alopecia10,11 and hair loss induced by numerous honeybee stings,12 and these diagnoses should be suspected in patients with a history of ants on their pillow or in those from endemic areas.
No specific treatment is indicated in cases of ant-induced alopecia because hair usually regrows to its normal length without intervention.
- Shamsadini S. Localized scalp hair shedding caused by Pheidole ants and overview of similar case reports. Dermatol Online J. 2003;9:12.
- Aghaei S, Sodaifi M. Circumscribed scalp hair loss following multiple hair-cutter ant invasion. Dermatol Online J. 2004;10:14.
- Mortazavi M, Mansouri P. Ant-induced alopecia: report of 2 cases and review of the literature. Dermatol Online J. 2004;10:19.
- Kapdağli S, Seçkin D, Baba M, et al. Localized hair breakage caused by ants. Pediatr Dermatol. 2006;23:519-520.
- Ogata K. Toxonomy and biology of the genus Pheidole of Japan. Nature and Insects. 1981;16:17-22.
- Radmanesh M, Mousavipour M. Alopecia induced by ants. Trans R Soc Trop Med Hyg. 1999;93:427.
- Hölldobler B, Wilson EO. The Ants. Cambridge, MA: Harvard University Press; 1990.
- Wilson EO. Pheidole in the New World: A Dominant Hyperdiverse Ant Genus. Cambridge MA: Harvard University Press; 2003.
- Veraldi S, Lunardon L, Francia C, et al. Alopecia caused by the “barber ant” Pheidole pallidula. Int J Dermatol. 2008;47:1329-1330.
- Marshall J. Alopecia after tick bite. S Afr Med J. 1966;40: 555-556.
- Heyl T. Tick bite alopecia. Clin Exp Dermatol. 1982;7: 537-542.
- Sharma AK, Sharma RC, Sharma NL. Diffuse hair loss following multiple honeybee stings. Dermatology. 1997;195:305.
- Shamsadini S. Localized scalp hair shedding caused by Pheidole ants and overview of similar case reports. Dermatol Online J. 2003;9:12.
- Aghaei S, Sodaifi M. Circumscribed scalp hair loss following multiple hair-cutter ant invasion. Dermatol Online J. 2004;10:14.
- Mortazavi M, Mansouri P. Ant-induced alopecia: report of 2 cases and review of the literature. Dermatol Online J. 2004;10:19.
- Kapdağli S, Seçkin D, Baba M, et al. Localized hair breakage caused by ants. Pediatr Dermatol. 2006;23:519-520.
- Ogata K. Toxonomy and biology of the genus Pheidole of Japan. Nature and Insects. 1981;16:17-22.
- Radmanesh M, Mousavipour M. Alopecia induced by ants. Trans R Soc Trop Med Hyg. 1999;93:427.
- Hölldobler B, Wilson EO. The Ants. Cambridge, MA: Harvard University Press; 1990.
- Wilson EO. Pheidole in the New World: A Dominant Hyperdiverse Ant Genus. Cambridge MA: Harvard University Press; 2003.
- Veraldi S, Lunardon L, Francia C, et al. Alopecia caused by the “barber ant” Pheidole pallidula. Int J Dermatol. 2008;47:1329-1330.
- Marshall J. Alopecia after tick bite. S Afr Med J. 1966;40: 555-556.
- Heyl T. Tick bite alopecia. Clin Exp Dermatol. 1982;7: 537-542.
- Sharma AK, Sharma RC, Sharma NL. Diffuse hair loss following multiple honeybee stings. Dermatology. 1997;195:305.
Practice Points
- Ant-induced alopecia should be considered in the differential diagnosis for patients from endemic regions (eg, Iran, Turkey) with new-onset localized hair loss or in patients recently visiting those areas with a concordant history.
- Ant-induced alopecia is thought to result from mechanical and/or chemical breakage, most commonly caused by Pheidole ants, leaving follicles intact and allowing for hair regrowth without treatment through the normal hair cycle.
