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The Diagnosis: Nodular Hidradenoma

Nodular hidradenomas (NHs) are rare benign cutaneous adnexal neoplasms first described in 1949 as clear cell papillary carcinomas.¹ Since then, various terms have been used to describe this entity, such as eccrine acrospiroma, solid-cystic hidradenoma, and clear cell hidradenoma.² Review of the literature revealed a female predominance (2:1 ratio) and a mean age at presentation of 37.2 years.^3,4 Nodular hidradenoma presents as an asymptomatic, solitary, mobile, firm nodule with intact overlying skin. Rarely, multiple nodules may occur.³ Some tumors display ulceration and serous fluid leakage.⁵ They occur most commonly on the scalp, face, and upper extremities with an average size of 2 cm.³ Rapid growth of the tumor may signal a malignant change.⁶

Histopathology reveals a lobulated, circumscribed, symmetrical tumor with dermal nests of epithelial cells that are polygonal with eosinophilic cytoplasm forming ductlike spaces (Figure). However, clear cell changes and squamous differentiation may be prominent features. Cystic spaces may result from tumor cell degeneration. Most tumors are encased by collagenous fibrous tissue and rarely have epidermal attachments.³

Anastomosing aggregates of squamous cells forming ductlike spaces were viewed on low-power magnification (A)(H&E, original magnification ×10). On higher power there were ductlike spaces and eosinophilic hyalinized stroma entrapped by the bland-appearing squamous proliferation (B)(H&E, original magnification ×20).

Nodular hidradenoma traditionally has been considered to be of eccrine origin, but more recent literature indicates that the majority of NHs are of apocrine origin. Histologically, apocrine tumors display eosinophilic secretion, mucinous epithelium, squamous or sebaceous differentiation, and decapitation secretion, whereas eccrine tumors are identified by their lack of specific features.³

Nodular hidradenoma may recur after excision. Malignant transformation is rare. In one review, 6.7% (6/89) of NHs were malignant, characterized by abnormal mitoses, nuclear atypia, and necrosis.⁴ Malignant NH or nodular hidradenocarcinoma behaves aggressively with up to an 86% local recurrence and 60% rate of metastasis within 2 years.⁶ Survival time is inversely proportional to the size of the tumor and is generally poor, with a 5-year disease-free survival of less than 30%.^6,7

Treatment of NH is achieved through primary excision or Mohs micrographic surgery; however, treatment of nodular hidradenocarcinoma is controversial and typically begins with wide local excision but may involve lymph node dissection if necessary. Use of adjuvant chemotherapy and radiation therapy for metastases warrants more clinical studies, as it is a rare occurrence.⁶ Our patient planned to undergo a total excision of the benign nodule once she healed from the biopsy; however, she was lost to follow-up, as she moved out of state.

The Diagnosis: Nodular Hidradenoma

Nodular hidradenomas (NHs) are rare benign cutaneous adnexal neoplasms first described in 1949 as clear cell papillary carcinomas.¹ Since then, various terms have been used to describe this entity, such as eccrine acrospiroma, solid-cystic hidradenoma, and clear cell hidradenoma.² Review of the literature revealed a female predominance (2:1 ratio) and a mean age at presentation of 37.2 years.^3,4 Nodular hidradenoma presents as an asymptomatic, solitary, mobile, firm nodule with intact overlying skin. Rarely, multiple nodules may occur.³ Some tumors display ulceration and serous fluid leakage.⁵ They occur most commonly on the scalp, face, and upper extremities with an average size of 2 cm.³ Rapid growth of the tumor may signal a malignant change.⁶

Histopathology reveals a lobulated, circumscribed, symmetrical tumor with dermal nests of epithelial cells that are polygonal with eosinophilic cytoplasm forming ductlike spaces (Figure). However, clear cell changes and squamous differentiation may be prominent features. Cystic spaces may result from tumor cell degeneration. Most tumors are encased by collagenous fibrous tissue and rarely have epidermal attachments.³

Anastomosing aggregates of squamous cells forming ductlike spaces were viewed on low-power magnification (A)(H&E, original magnification ×10). On higher power there were ductlike spaces and eosinophilic hyalinized stroma entrapped by the bland-appearing squamous proliferation (B)(H&E, original magnification ×20).

Nodular hidradenoma traditionally has been considered to be of eccrine origin, but more recent literature indicates that the majority of NHs are of apocrine origin. Histologically, apocrine tumors display eosinophilic secretion, mucinous epithelium, squamous or sebaceous differentiation, and decapitation secretion, whereas eccrine tumors are identified by their lack of specific features.³

Nodular hidradenoma may recur after excision. Malignant transformation is rare. In one review, 6.7% (6/89) of NHs were malignant, characterized by abnormal mitoses, nuclear atypia, and necrosis.⁴ Malignant NH or nodular hidradenocarcinoma behaves aggressively with up to an 86% local recurrence and 60% rate of metastasis within 2 years.⁶ Survival time is inversely proportional to the size of the tumor and is generally poor, with a 5-year disease-free survival of less than 30%.^6,7

Treatment of NH is achieved through primary excision or Mohs micrographic surgery; however, treatment of nodular hidradenocarcinoma is controversial and typically begins with wide local excision but may involve lymph node dissection if necessary. Use of adjuvant chemotherapy and radiation therapy for metastases warrants more clinical studies, as it is a rare occurrence.⁶ Our patient planned to undergo a total excision of the benign nodule once she healed from the biopsy; however, she was lost to follow-up, as she moved out of state.

The Diagnosis: Nodular Hidradenoma

Nodular hidradenomas (NHs) are rare benign cutaneous adnexal neoplasms first described in 1949 as clear cell papillary carcinomas.¹ Since then, various terms have been used to describe this entity, such as eccrine acrospiroma, solid-cystic hidradenoma, and clear cell hidradenoma.² Review of the literature revealed a female predominance (2:1 ratio) and a mean age at presentation of 37.2 years.^3,4 Nodular hidradenoma presents as an asymptomatic, solitary, mobile, firm nodule with intact overlying skin. Rarely, multiple nodules may occur.³ Some tumors display ulceration and serous fluid leakage.⁵ They occur most commonly on the scalp, face, and upper extremities with an average size of 2 cm.³ Rapid growth of the tumor may signal a malignant change.⁶

Histopathology reveals a lobulated, circumscribed, symmetrical tumor with dermal nests of epithelial cells that are polygonal with eosinophilic cytoplasm forming ductlike spaces (Figure). However, clear cell changes and squamous differentiation may be prominent features. Cystic spaces may result from tumor cell degeneration. Most tumors are encased by collagenous fibrous tissue and rarely have epidermal attachments.³

Anastomosing aggregates of squamous cells forming ductlike spaces were viewed on low-power magnification (A)(H&E, original magnification ×10). On higher power there were ductlike spaces and eosinophilic hyalinized stroma entrapped by the bland-appearing squamous proliferation (B)(H&E, original magnification ×20).

Nodular hidradenoma traditionally has been considered to be of eccrine origin, but more recent literature indicates that the majority of NHs are of apocrine origin. Histologically, apocrine tumors display eosinophilic secretion, mucinous epithelium, squamous or sebaceous differentiation, and decapitation secretion, whereas eccrine tumors are identified by their lack of specific features.³

Nodular hidradenoma may recur after excision. Malignant transformation is rare. In one review, 6.7% (6/89) of NHs were malignant, characterized by abnormal mitoses, nuclear atypia, and necrosis.⁴ Malignant NH or nodular hidradenocarcinoma behaves aggressively with up to an 86% local recurrence and 60% rate of metastasis within 2 years.⁶ Survival time is inversely proportional to the size of the tumor and is generally poor, with a 5-year disease-free survival of less than 30%.^6,7

Treatment of NH is achieved through primary excision or Mohs micrographic surgery; however, treatment of nodular hidradenocarcinoma is controversial and typically begins with wide local excision but may involve lymph node dissection if necessary. Use of adjuvant chemotherapy and radiation therapy for metastases warrants more clinical studies, as it is a rare occurrence.⁶ Our patient planned to undergo a total excision of the benign nodule once she healed from the biopsy; however, she was lost to follow-up, as she moved out of state.

The Diagnosis: Pancreatic Panniculitis

The biopsy specimen revealed necrosis of the panniculus with “ghost” cells (Figure). Calcification was encountered. Changes of vasculitis were not identified and fungal organisms were not noted. The histopathologic findings supported a diagnosis of pancreatic panniculitis.

Punch biopsy revealed necrosis of the panniculus with “ghost” cells, and calcification was encountered (H&E, original magnification ×20).

Pancreatic panniculitis has been associated with pancreatitis, pancreatic carcinoma, pancreatic pseudocysts, congenital abnormalities of the pancreas, and drug-induced pancreatitis.¹ Skin lesions may herald a diagnosis of pancreatic disease in an outpatient and should prompt thorough clinical evaluation when encountered in an outpatient setting. Our patient first developed tender nodules on the left shin 2 to 3 weeks prior to presentation. She reported that her initial nodules were flesh colored but then became erythematous and tender over 1 week’s time. The patient’s history was remarkable for ovarian cancer. She had been hospitalized 2 weeks prior to presentation for abdominal pain and ascites. Imaging studies revealed a cystic lesion in the head of the pancreas. The pancreas was traumatized during a peritoneal tap. Her nodules developed shortly thereafter and were distributed on the arms, legs, back, and abdomen.

Pancreatic tumors or inflammation are thought to trigger pancreatic panniculitis by releasing enzymes. Pancreatic enzymes such as lipase are thought to play a role in the development of pancreatic panniculitis by entering the vascular system and leading to fat necrosis.^2,3 Biopsy reveals necrosis of adipocytes in the center of fat lobules.⁴ Ghost cells result from hydrolytic activity of enzymes on the fat cells followed by calcium deposition. A report indicates that fungal infection or gout also can cause changes that mimic pancreatic panniculitis.⁵

Other entities in the differential diagnosis can be excluded by biopsy. Polyarteritis nodosa is a vasculitis. Although panniculitis may be seen in polyarteritis as a secondary phenomenon, lesions are centered around blood vessels and often eventuate in ulceration.⁶ Subcutaneous fungal infection typically reveals organisms on periodic acid–Schiff stain.⁷ Pyoderma gangrenosum is associated with ulceration and a neutrophilic infiltrate that is often centered around a central pilosebaceous unit in developing lesions.⁸ Erythema nodosum is a panniculitis in which septal inflammation predominates.⁹ These differential diagnoses of pancreatic panniculitis are summarized in the Table.

Pancreatic panniculitis can be associated with acute arthritis and inflammation of periarticular fat.¹⁰ Treatment of pancreatic panniculitis is usually focused on the underlying pancreatic disease.^11,12 Our patient benefited from analgesic therapy and her lesions improved on follow-up. Clinicians encountering a patient with new tender nodules should be prompted to perform a biopsy. When histopathologic evaluation reveals ghosted adipocytes, pancreatic panniculitis should be suspected and clinical evaluation undertaken.

The Diagnosis: Pancreatic Panniculitis

The biopsy specimen revealed necrosis of the panniculus with “ghost” cells (Figure). Calcification was encountered. Changes of vasculitis were not identified and fungal organisms were not noted. The histopathologic findings supported a diagnosis of pancreatic panniculitis.

Punch biopsy revealed necrosis of the panniculus with “ghost” cells, and calcification was encountered (H&E, original magnification ×20).

Pancreatic panniculitis has been associated with pancreatitis, pancreatic carcinoma, pancreatic pseudocysts, congenital abnormalities of the pancreas, and drug-induced pancreatitis.¹ Skin lesions may herald a diagnosis of pancreatic disease in an outpatient and should prompt thorough clinical evaluation when encountered in an outpatient setting. Our patient first developed tender nodules on the left shin 2 to 3 weeks prior to presentation. She reported that her initial nodules were flesh colored but then became erythematous and tender over 1 week’s time. The patient’s history was remarkable for ovarian cancer. She had been hospitalized 2 weeks prior to presentation for abdominal pain and ascites. Imaging studies revealed a cystic lesion in the head of the pancreas. The pancreas was traumatized during a peritoneal tap. Her nodules developed shortly thereafter and were distributed on the arms, legs, back, and abdomen.

Pancreatic tumors or inflammation are thought to trigger pancreatic panniculitis by releasing enzymes. Pancreatic enzymes such as lipase are thought to play a role in the development of pancreatic panniculitis by entering the vascular system and leading to fat necrosis.^2,3 Biopsy reveals necrosis of adipocytes in the center of fat lobules.⁴ Ghost cells result from hydrolytic activity of enzymes on the fat cells followed by calcium deposition. A report indicates that fungal infection or gout also can cause changes that mimic pancreatic panniculitis.⁵

Other entities in the differential diagnosis can be excluded by biopsy. Polyarteritis nodosa is a vasculitis. Although panniculitis may be seen in polyarteritis as a secondary phenomenon, lesions are centered around blood vessels and often eventuate in ulceration.⁶ Subcutaneous fungal infection typically reveals organisms on periodic acid–Schiff stain.⁷ Pyoderma gangrenosum is associated with ulceration and a neutrophilic infiltrate that is often centered around a central pilosebaceous unit in developing lesions.⁸ Erythema nodosum is a panniculitis in which septal inflammation predominates.⁹ These differential diagnoses of pancreatic panniculitis are summarized in the Table.

Pancreatic panniculitis can be associated with acute arthritis and inflammation of periarticular fat.¹⁰ Treatment of pancreatic panniculitis is usually focused on the underlying pancreatic disease.^11,12 Our patient benefited from analgesic therapy and her lesions improved on follow-up. Clinicians encountering a patient with new tender nodules should be prompted to perform a biopsy. When histopathologic evaluation reveals ghosted adipocytes, pancreatic panniculitis should be suspected and clinical evaluation undertaken.

The Diagnosis: Pancreatic Panniculitis

The biopsy specimen revealed necrosis of the panniculus with “ghost” cells (Figure). Calcification was encountered. Changes of vasculitis were not identified and fungal organisms were not noted. The histopathologic findings supported a diagnosis of pancreatic panniculitis.

Punch biopsy revealed necrosis of the panniculus with “ghost” cells, and calcification was encountered (H&E, original magnification ×20).

Pancreatic panniculitis has been associated with pancreatitis, pancreatic carcinoma, pancreatic pseudocysts, congenital abnormalities of the pancreas, and drug-induced pancreatitis.¹ Skin lesions may herald a diagnosis of pancreatic disease in an outpatient and should prompt thorough clinical evaluation when encountered in an outpatient setting. Our patient first developed tender nodules on the left shin 2 to 3 weeks prior to presentation. She reported that her initial nodules were flesh colored but then became erythematous and tender over 1 week’s time. The patient’s history was remarkable for ovarian cancer. She had been hospitalized 2 weeks prior to presentation for abdominal pain and ascites. Imaging studies revealed a cystic lesion in the head of the pancreas. The pancreas was traumatized during a peritoneal tap. Her nodules developed shortly thereafter and were distributed on the arms, legs, back, and abdomen.

Pancreatic tumors or inflammation are thought to trigger pancreatic panniculitis by releasing enzymes. Pancreatic enzymes such as lipase are thought to play a role in the development of pancreatic panniculitis by entering the vascular system and leading to fat necrosis.^2,3 Biopsy reveals necrosis of adipocytes in the center of fat lobules.⁴ Ghost cells result from hydrolytic activity of enzymes on the fat cells followed by calcium deposition. A report indicates that fungal infection or gout also can cause changes that mimic pancreatic panniculitis.⁵

Other entities in the differential diagnosis can be excluded by biopsy. Polyarteritis nodosa is a vasculitis. Although panniculitis may be seen in polyarteritis as a secondary phenomenon, lesions are centered around blood vessels and often eventuate in ulceration.⁶ Subcutaneous fungal infection typically reveals organisms on periodic acid–Schiff stain.⁷ Pyoderma gangrenosum is associated with ulceration and a neutrophilic infiltrate that is often centered around a central pilosebaceous unit in developing lesions.⁸ Erythema nodosum is a panniculitis in which septal inflammation predominates.⁹ These differential diagnoses of pancreatic panniculitis are summarized in the Table.

Pancreatic panniculitis can be associated with acute arthritis and inflammation of periarticular fat.¹⁰ Treatment of pancreatic panniculitis is usually focused on the underlying pancreatic disease.^11,12 Our patient benefited from analgesic therapy and her lesions improved on follow-up. Clinicians encountering a patient with new tender nodules should be prompted to perform a biopsy. When histopathologic evaluation reveals ghosted adipocytes, pancreatic panniculitis should be suspected and clinical evaluation undertaken.

The Diagnosis: Onychomadesis Following Hand-foot-and-mouth Disease

In 1846, Joseph Honoré Simon Beau described specific diagnostic signs manifested in the nails during various disease states.¹ He suggested that the width of the nail plate depression correlated with the duration of illness. Since then, the correlation of nail changes during times of illness has been confirmed. The term Beau lines currently is used to describe transverse ridging of the nail plate due to transient arrest in nail plate formation.¹ Onychomadesis is believed to be an extreme form of Beau lines in which the whole thickness of the nail plate is affected, resulting in its separation from the proximal nail fold and shedding of the nail plate.

Nail plate detachment in onychomadesis is due to a severe insult that results in complete arrest of the nail matrix activity. Onychomadesis has a wide spectrum of clinical presentations, ranging from mild transverse ridges of the nail plate (Beau lines) to complete nail shedding.² Trauma is the leading cause of single-digit onychomadesis, while multiple-digit onychomadesis usually is caused by a systemic disease (eg, blistering illnesses). Cases of multiple-nail onychomadesis have been reported following hand-foot-and-mouth disease (HFMD), though the majority of cases of HFMD do not present with onychomadesis.

Hand-foot-and-mouth disease is most commonly caused by 2 types of intestinal strains of Human enterovirus A: (1) coxsackievirus A6 (CVA6) or A16 (CVA16) and (2) enterovirus 71.^3,4 Symptoms of HFMD include fever and sore throat followed by the development of oral ulcerations 1 to 2 days later. A vesicular or maculopapular rash can then develop on the hands, feet, and mouth. Complications following HFMD are rare but can include encephalitis, meningitis, and pneumonia. Symptoms typically resolve after 6 days without any treatment.³

A cluster of onychomadesis cases following HFMD outbreaks have been reported in Europe, Asia, and the United States. In some reports, causative viral strains have been identified. After a national HFMD outbreak in Finland in fall 2008, investigators isolated strains of CVA6 in the shedded nails of sibling patients.⁴ The CVA6 strain was found to be the primary pathogen causing that particular HFMD outbreak and onychomadesis was a hallmark presentation of this viral epidemic. Previously, HFMD outbreaks were known to be caused by CVA16 or enterovirus 71, with enterovirus 71 strains occurring mostly in Southeast Asia and Australia.⁴ In a report from Taiwan, the incidence of onychomadesis after CVA6 infection was 37% (48/130) as compared to 5% (7/145) in cases with non-CVA6 causative strains. Among patients with onychomadesis, 69% (33/48) were reported to experience concurrent palmoplantar desquamation before or during presentation of nail changes.⁵

Another Finnish study investigated an atypical outbreak of HFMD that occurred primarily in adult patients.⁶ Many of these patients also had onychomadesis several weeks following HFMD. Of 317 cases, human enteroviruses were detected in specimens from 212 cases (67%), including both children and adults. Two human enterovirus types—CVA6 (71% [83/117]) and coxsackievirus A10 (28% [33/117])—were identified as the causative agents of the outbreak. One genetic variant of CVA6 predominated, but 3 other genetically distinct CVA6 strains also were found.⁶ The 2008 HFMD outbreak in Finland was found to be caused by 2 concomitantly circulating human enteroviruses, which up until now have been infrequently detected together as causative agents of HFMD. Onychomadesis was a common occurrence in the Finnish HFMD outbreak, which has been previously linked to CVA6. The co-circulation of CVA6 and coxsackievirus A10 suggests an endemic emergence of new genetic variants of these enteroviruses.⁶

There also have been several reports of onychomadesis outbreaks in Spain, 2 of which occurred in nursery settings. One report noted that patients with a history of HFMD were 14 times more likely to develop onychomadesis (relative risk, 14; 95% confidence interval, 4.57-42.86).³ There also was a noted difference in prevalence of onychomadesis regarding age: a 55% (18/33) occurrence rate was noted in the youngest age group (9–23 months), 30% (8/27) in the middle age group (24–32 months), and 4% (1/28) in the oldest age group (33–42 months). Occurrence of onychomadesis and nail plate changes was observed on average 40 days after HFMD, and an average of 4 nails were shed per case.³ A report investigating a separate HFMD outbreak in Spain found a high percentage of onychomadesis (96% [298/311]) occurring in children younger than 6 years. This outbreak, which occurred in the metropolitan area of Valencia, was associated with an outbreak of HFMD primarily caused by coxsackievirus A10.⁷ A third Spanish study uncovered a high occurrence of onychomadesis in a nursery setting as a consequence of HFMD, where 92% (11/12) of onychomadesis cases were preceded by HFMD 2 months prior.⁸

A case series reported in Chicago, Illinois, in the late 1990s identified 5 pediatric patients with HFMD associated with Beau lines and onychomadesis.¹ Only 3 of 5 (60%) patients had a fever; therefore, fever-induced nail matrix arrest was ruled out as the inciting factor of the nail changes seen. All patients were given over-the-counter analgesics and 2 received antibiotics (amoxicillin for the first 48 hours). None of these medications have been implicated as plausible causes of nail matrix arrest. Two patients were siblings and the rest were not related. None of the patients had a history of close physical proximity (eg, attendance at the same day care or school). All 5 patients developed HFMD within 4 weeks of one another, and all were from the suburbs of Chicago (with 4 of 5 [80%] patients living within a 60-mile radius of each other). Although the causative viral strain was not isolated, the authors concluded that all the patients were likely to have been infected by the same virus due to the general vicinity of the patients to each other. Furthermore, the collective case reports likely represented an HFMD epidemic caused by a particular strain that can induce onychomadesis.¹

Supportive care for the viral illness paired with protection of the nail bed until new nail growth occurs is ideal, which requires maintaining short nails and using adhesive bandages over the affected nails to avoid snagging the nail or ripping off the partially attached nails.

Onychomadesis can follow HFMD, especially in cases caused by CVA6. Cases of onychomadesis are mild and self-limited. When onychomadesis is noted, historical review of viral illnesses within 1 to 2 months prior to nail changes often will identify the causative disease.

The Diagnosis: Onychomadesis Following Hand-foot-and-mouth Disease

In 1846, Joseph Honoré Simon Beau described specific diagnostic signs manifested in the nails during various disease states.¹ He suggested that the width of the nail plate depression correlated with the duration of illness. Since then, the correlation of nail changes during times of illness has been confirmed. The term Beau lines currently is used to describe transverse ridging of the nail plate due to transient arrest in nail plate formation.¹ Onychomadesis is believed to be an extreme form of Beau lines in which the whole thickness of the nail plate is affected, resulting in its separation from the proximal nail fold and shedding of the nail plate.

Nail plate detachment in onychomadesis is due to a severe insult that results in complete arrest of the nail matrix activity. Onychomadesis has a wide spectrum of clinical presentations, ranging from mild transverse ridges of the nail plate (Beau lines) to complete nail shedding.² Trauma is the leading cause of single-digit onychomadesis, while multiple-digit onychomadesis usually is caused by a systemic disease (eg, blistering illnesses). Cases of multiple-nail onychomadesis have been reported following hand-foot-and-mouth disease (HFMD), though the majority of cases of HFMD do not present with onychomadesis.

Hand-foot-and-mouth disease is most commonly caused by 2 types of intestinal strains of Human enterovirus A: (1) coxsackievirus A6 (CVA6) or A16 (CVA16) and (2) enterovirus 71.^3,4 Symptoms of HFMD include fever and sore throat followed by the development of oral ulcerations 1 to 2 days later. A vesicular or maculopapular rash can then develop on the hands, feet, and mouth. Complications following HFMD are rare but can include encephalitis, meningitis, and pneumonia. Symptoms typically resolve after 6 days without any treatment.³

A cluster of onychomadesis cases following HFMD outbreaks have been reported in Europe, Asia, and the United States. In some reports, causative viral strains have been identified. After a national HFMD outbreak in Finland in fall 2008, investigators isolated strains of CVA6 in the shedded nails of sibling patients.⁴ The CVA6 strain was found to be the primary pathogen causing that particular HFMD outbreak and onychomadesis was a hallmark presentation of this viral epidemic. Previously, HFMD outbreaks were known to be caused by CVA16 or enterovirus 71, with enterovirus 71 strains occurring mostly in Southeast Asia and Australia.⁴ In a report from Taiwan, the incidence of onychomadesis after CVA6 infection was 37% (48/130) as compared to 5% (7/145) in cases with non-CVA6 causative strains. Among patients with onychomadesis, 69% (33/48) were reported to experience concurrent palmoplantar desquamation before or during presentation of nail changes.⁵

Another Finnish study investigated an atypical outbreak of HFMD that occurred primarily in adult patients.⁶ Many of these patients also had onychomadesis several weeks following HFMD. Of 317 cases, human enteroviruses were detected in specimens from 212 cases (67%), including both children and adults. Two human enterovirus types—CVA6 (71% [83/117]) and coxsackievirus A10 (28% [33/117])—were identified as the causative agents of the outbreak. One genetic variant of CVA6 predominated, but 3 other genetically distinct CVA6 strains also were found.⁶ The 2008 HFMD outbreak in Finland was found to be caused by 2 concomitantly circulating human enteroviruses, which up until now have been infrequently detected together as causative agents of HFMD. Onychomadesis was a common occurrence in the Finnish HFMD outbreak, which has been previously linked to CVA6. The co-circulation of CVA6 and coxsackievirus A10 suggests an endemic emergence of new genetic variants of these enteroviruses.⁶

There also have been several reports of onychomadesis outbreaks in Spain, 2 of which occurred in nursery settings. One report noted that patients with a history of HFMD were 14 times more likely to develop onychomadesis (relative risk, 14; 95% confidence interval, 4.57-42.86).³ There also was a noted difference in prevalence of onychomadesis regarding age: a 55% (18/33) occurrence rate was noted in the youngest age group (9–23 months), 30% (8/27) in the middle age group (24–32 months), and 4% (1/28) in the oldest age group (33–42 months). Occurrence of onychomadesis and nail plate changes was observed on average 40 days after HFMD, and an average of 4 nails were shed per case.³ A report investigating a separate HFMD outbreak in Spain found a high percentage of onychomadesis (96% [298/311]) occurring in children younger than 6 years. This outbreak, which occurred in the metropolitan area of Valencia, was associated with an outbreak of HFMD primarily caused by coxsackievirus A10.⁷ A third Spanish study uncovered a high occurrence of onychomadesis in a nursery setting as a consequence of HFMD, where 92% (11/12) of onychomadesis cases were preceded by HFMD 2 months prior.⁸

A case series reported in Chicago, Illinois, in the late 1990s identified 5 pediatric patients with HFMD associated with Beau lines and onychomadesis.¹ Only 3 of 5 (60%) patients had a fever; therefore, fever-induced nail matrix arrest was ruled out as the inciting factor of the nail changes seen. All patients were given over-the-counter analgesics and 2 received antibiotics (amoxicillin for the first 48 hours). None of these medications have been implicated as plausible causes of nail matrix arrest. Two patients were siblings and the rest were not related. None of the patients had a history of close physical proximity (eg, attendance at the same day care or school). All 5 patients developed HFMD within 4 weeks of one another, and all were from the suburbs of Chicago (with 4 of 5 [80%] patients living within a 60-mile radius of each other). Although the causative viral strain was not isolated, the authors concluded that all the patients were likely to have been infected by the same virus due to the general vicinity of the patients to each other. Furthermore, the collective case reports likely represented an HFMD epidemic caused by a particular strain that can induce onychomadesis.¹

Supportive care for the viral illness paired with protection of the nail bed until new nail growth occurs is ideal, which requires maintaining short nails and using adhesive bandages over the affected nails to avoid snagging the nail or ripping off the partially attached nails.

Onychomadesis can follow HFMD, especially in cases caused by CVA6. Cases of onychomadesis are mild and self-limited. When onychomadesis is noted, historical review of viral illnesses within 1 to 2 months prior to nail changes often will identify the causative disease.

The Diagnosis: Onychomadesis Following Hand-foot-and-mouth Disease

In 1846, Joseph Honoré Simon Beau described specific diagnostic signs manifested in the nails during various disease states.¹ He suggested that the width of the nail plate depression correlated with the duration of illness. Since then, the correlation of nail changes during times of illness has been confirmed. The term Beau lines currently is used to describe transverse ridging of the nail plate due to transient arrest in nail plate formation.¹ Onychomadesis is believed to be an extreme form of Beau lines in which the whole thickness of the nail plate is affected, resulting in its separation from the proximal nail fold and shedding of the nail plate.

Nail plate detachment in onychomadesis is due to a severe insult that results in complete arrest of the nail matrix activity. Onychomadesis has a wide spectrum of clinical presentations, ranging from mild transverse ridges of the nail plate (Beau lines) to complete nail shedding.² Trauma is the leading cause of single-digit onychomadesis, while multiple-digit onychomadesis usually is caused by a systemic disease (eg, blistering illnesses). Cases of multiple-nail onychomadesis have been reported following hand-foot-and-mouth disease (HFMD), though the majority of cases of HFMD do not present with onychomadesis.

Hand-foot-and-mouth disease is most commonly caused by 2 types of intestinal strains of Human enterovirus A: (1) coxsackievirus A6 (CVA6) or A16 (CVA16) and (2) enterovirus 71.^3,4 Symptoms of HFMD include fever and sore throat followed by the development of oral ulcerations 1 to 2 days later. A vesicular or maculopapular rash can then develop on the hands, feet, and mouth. Complications following HFMD are rare but can include encephalitis, meningitis, and pneumonia. Symptoms typically resolve after 6 days without any treatment.³

A cluster of onychomadesis cases following HFMD outbreaks have been reported in Europe, Asia, and the United States. In some reports, causative viral strains have been identified. After a national HFMD outbreak in Finland in fall 2008, investigators isolated strains of CVA6 in the shedded nails of sibling patients.⁴ The CVA6 strain was found to be the primary pathogen causing that particular HFMD outbreak and onychomadesis was a hallmark presentation of this viral epidemic. Previously, HFMD outbreaks were known to be caused by CVA16 or enterovirus 71, with enterovirus 71 strains occurring mostly in Southeast Asia and Australia.⁴ In a report from Taiwan, the incidence of onychomadesis after CVA6 infection was 37% (48/130) as compared to 5% (7/145) in cases with non-CVA6 causative strains. Among patients with onychomadesis, 69% (33/48) were reported to experience concurrent palmoplantar desquamation before or during presentation of nail changes.⁵

Another Finnish study investigated an atypical outbreak of HFMD that occurred primarily in adult patients.⁶ Many of these patients also had onychomadesis several weeks following HFMD. Of 317 cases, human enteroviruses were detected in specimens from 212 cases (67%), including both children and adults. Two human enterovirus types—CVA6 (71% [83/117]) and coxsackievirus A10 (28% [33/117])—were identified as the causative agents of the outbreak. One genetic variant of CVA6 predominated, but 3 other genetically distinct CVA6 strains also were found.⁶ The 2008 HFMD outbreak in Finland was found to be caused by 2 concomitantly circulating human enteroviruses, which up until now have been infrequently detected together as causative agents of HFMD. Onychomadesis was a common occurrence in the Finnish HFMD outbreak, which has been previously linked to CVA6. The co-circulation of CVA6 and coxsackievirus A10 suggests an endemic emergence of new genetic variants of these enteroviruses.⁶

There also have been several reports of onychomadesis outbreaks in Spain, 2 of which occurred in nursery settings. One report noted that patients with a history of HFMD were 14 times more likely to develop onychomadesis (relative risk, 14; 95% confidence interval, 4.57-42.86).³ There also was a noted difference in prevalence of onychomadesis regarding age: a 55% (18/33) occurrence rate was noted in the youngest age group (9–23 months), 30% (8/27) in the middle age group (24–32 months), and 4% (1/28) in the oldest age group (33–42 months). Occurrence of onychomadesis and nail plate changes was observed on average 40 days after HFMD, and an average of 4 nails were shed per case.³ A report investigating a separate HFMD outbreak in Spain found a high percentage of onychomadesis (96% [298/311]) occurring in children younger than 6 years. This outbreak, which occurred in the metropolitan area of Valencia, was associated with an outbreak of HFMD primarily caused by coxsackievirus A10.⁷ A third Spanish study uncovered a high occurrence of onychomadesis in a nursery setting as a consequence of HFMD, where 92% (11/12) of onychomadesis cases were preceded by HFMD 2 months prior.⁸

A case series reported in Chicago, Illinois, in the late 1990s identified 5 pediatric patients with HFMD associated with Beau lines and onychomadesis.¹ Only 3 of 5 (60%) patients had a fever; therefore, fever-induced nail matrix arrest was ruled out as the inciting factor of the nail changes seen. All patients were given over-the-counter analgesics and 2 received antibiotics (amoxicillin for the first 48 hours). None of these medications have been implicated as plausible causes of nail matrix arrest. Two patients were siblings and the rest were not related. None of the patients had a history of close physical proximity (eg, attendance at the same day care or school). All 5 patients developed HFMD within 4 weeks of one another, and all were from the suburbs of Chicago (with 4 of 5 [80%] patients living within a 60-mile radius of each other). Although the causative viral strain was not isolated, the authors concluded that all the patients were likely to have been infected by the same virus due to the general vicinity of the patients to each other. Furthermore, the collective case reports likely represented an HFMD epidemic caused by a particular strain that can induce onychomadesis.¹

Supportive care for the viral illness paired with protection of the nail bed until new nail growth occurs is ideal, which requires maintaining short nails and using adhesive bandages over the affected nails to avoid snagging the nail or ripping off the partially attached nails.

Onychomadesis can follow HFMD, especially in cases caused by CVA6. Cases of onychomadesis are mild and self-limited. When onychomadesis is noted, historical review of viral illnesses within 1 to 2 months prior to nail changes often will identify the causative disease.

The Diagnosis: Mycobacterium chelonae Arising Within a Tattoo

A 3-mm punch biopsy specimen was obtained from one of the plaques. Histopathology revealed an unremarkable epidermis with granulomatous collections of epithelioid histiocytes in association with neutrophils and lymphocytes in the dermis (Figure 1). Periodic acid–Schiff stain was negative for fungal organisms. Gram stain was negative for bacteria. Fite stain was positive for acid-fast bacilli (Figure 2). Clinical and histopathologic findings led to the initial diagnosis of a mycobacterial infection within the tattoo. The patient was empirically started on oral doxycycline 100 mg twice daily and oral clarithromycin 500 mg twice daily with mild improvement of the lesions over the next month. After 6 weeks the mycobacterial cultures were persistently negative and high-performance liquid chromatography was performed verifying the presence of Mycobacterium chelonae. Clarithromycin was continued and the doxycycline was replaced with oral trimethoprim-sulfamethoxazole (double strength) twice daily due to resistance. The patient was referred to an infectious disease specialist who concurred with the treatment regimen for a duration of 6 months to a year. A chest radiograph also was performed to rule out disseminated disease. Several months later the patient’s close friend presented with a similar infection that was acquired on the same day as our patient at the same tattoo parlor. The New York City Department of Health and Mental Hygiene was notified about these cases and informed us of other cases in New York State linked to contaminated tattoo ink.

Figure 1. Granulomatous collections of epithelioid histiocytes with neutrophilic and lymphocytic infiltrates in the dermis (H&E, original magnification ×4). Figure 2. Acid-fast organisms in the dermis (Fite, original magnification ×100).

Mycobacterium chelonae is a rapidly growing nontuberculous mycobacteria (Runyon group IV) that is found in nature and contaminated sources such as soil, lakes, sewage, and tap water.¹ Inoculation ofM chelonae through contaminated instruments leads to the formation of painful lesions, abscesses, fistulas, and granulomas that are extremely difficult to treat.² In our patient, M chelonae was most likely transmitted via contaminated tap water that was used to dilute the black tattoo ink to yield a gray color. Alternative sources are the ink itself or the container used to mix the ink.³Mycobacterium chelonae can cause infections in the skin, lungs, joints, bones, and eyes.⁴ With the exception of lung disease, trauma is the usual inciting factor. Disseminated infections are almost exclusively found in immunosuppressed individuals. Mycobacterium chelonae is typically found to grow on culture within 7 days. However, in our case there was no growth after 6 weeks of incubation. High-performance liquid chromatography analysis of mycolic acid is an alternative method of identifying mycobacteria. This technique verified the presence of M chelonae in our case when cultures were persistently negative.⁵

Mycobacterium chelonae is difficult to treat. The most common antibiotics used for treatment are clarithromycin, azithromycin, doxycycline, and linezolid.⁶ Studies of various antibiotics have shown that clarithromycin is the most effective macrolide against M chelonae.⁷ Tetracyclines also were studied in their effectiveness at treating nontuberculous mycobacteria infections but were found to have increased resistance to M chelonae.⁸ Although treatment regimens vary, the highest success rates are achieved with a minimum of 6 months of therapy using at least 2 drugs. Longer treatment is recommended for immunocompromised individuals.⁹

The case we present is important from a public health perspective. The tattoo industry and ink manufacturers should bemade aware of the risks of various infections from nonsterile techniques. Tattoo parlor employees should be advised of the risks of using nonsterile water for ink dilution and cleaning tattoo equipment. They also should be continuously educated on aseptic techniques.

The Diagnosis: Mycobacterium chelonae Arising Within a Tattoo

A 3-mm punch biopsy specimen was obtained from one of the plaques. Histopathology revealed an unremarkable epidermis with granulomatous collections of epithelioid histiocytes in association with neutrophils and lymphocytes in the dermis (Figure 1). Periodic acid–Schiff stain was negative for fungal organisms. Gram stain was negative for bacteria. Fite stain was positive for acid-fast bacilli (Figure 2). Clinical and histopathologic findings led to the initial diagnosis of a mycobacterial infection within the tattoo. The patient was empirically started on oral doxycycline 100 mg twice daily and oral clarithromycin 500 mg twice daily with mild improvement of the lesions over the next month. After 6 weeks the mycobacterial cultures were persistently negative and high-performance liquid chromatography was performed verifying the presence of Mycobacterium chelonae. Clarithromycin was continued and the doxycycline was replaced with oral trimethoprim-sulfamethoxazole (double strength) twice daily due to resistance. The patient was referred to an infectious disease specialist who concurred with the treatment regimen for a duration of 6 months to a year. A chest radiograph also was performed to rule out disseminated disease. Several months later the patient’s close friend presented with a similar infection that was acquired on the same day as our patient at the same tattoo parlor. The New York City Department of Health and Mental Hygiene was notified about these cases and informed us of other cases in New York State linked to contaminated tattoo ink.

Figure 1. Granulomatous collections of epithelioid histiocytes with neutrophilic and lymphocytic infiltrates in the dermis (H&E, original magnification ×4). Figure 2. Acid-fast organisms in the dermis (Fite, original magnification ×100).

Mycobacterium chelonae is a rapidly growing nontuberculous mycobacteria (Runyon group IV) that is found in nature and contaminated sources such as soil, lakes, sewage, and tap water.¹ Inoculation ofM chelonae through contaminated instruments leads to the formation of painful lesions, abscesses, fistulas, and granulomas that are extremely difficult to treat.² In our patient, M chelonae was most likely transmitted via contaminated tap water that was used to dilute the black tattoo ink to yield a gray color. Alternative sources are the ink itself or the container used to mix the ink.³Mycobacterium chelonae can cause infections in the skin, lungs, joints, bones, and eyes.⁴ With the exception of lung disease, trauma is the usual inciting factor. Disseminated infections are almost exclusively found in immunosuppressed individuals. Mycobacterium chelonae is typically found to grow on culture within 7 days. However, in our case there was no growth after 6 weeks of incubation. High-performance liquid chromatography analysis of mycolic acid is an alternative method of identifying mycobacteria. This technique verified the presence of M chelonae in our case when cultures were persistently negative.⁵

Mycobacterium chelonae is difficult to treat. The most common antibiotics used for treatment are clarithromycin, azithromycin, doxycycline, and linezolid.⁶ Studies of various antibiotics have shown that clarithromycin is the most effective macrolide against M chelonae.⁷ Tetracyclines also were studied in their effectiveness at treating nontuberculous mycobacteria infections but were found to have increased resistance to M chelonae.⁸ Although treatment regimens vary, the highest success rates are achieved with a minimum of 6 months of therapy using at least 2 drugs. Longer treatment is recommended for immunocompromised individuals.⁹

The case we present is important from a public health perspective. The tattoo industry and ink manufacturers should bemade aware of the risks of various infections from nonsterile techniques. Tattoo parlor employees should be advised of the risks of using nonsterile water for ink dilution and cleaning tattoo equipment. They also should be continuously educated on aseptic techniques.

The Diagnosis: Mycobacterium chelonae Arising Within a Tattoo

A 3-mm punch biopsy specimen was obtained from one of the plaques. Histopathology revealed an unremarkable epidermis with granulomatous collections of epithelioid histiocytes in association with neutrophils and lymphocytes in the dermis (Figure 1). Periodic acid–Schiff stain was negative for fungal organisms. Gram stain was negative for bacteria. Fite stain was positive for acid-fast bacilli (Figure 2). Clinical and histopathologic findings led to the initial diagnosis of a mycobacterial infection within the tattoo. The patient was empirically started on oral doxycycline 100 mg twice daily and oral clarithromycin 500 mg twice daily with mild improvement of the lesions over the next month. After 6 weeks the mycobacterial cultures were persistently negative and high-performance liquid chromatography was performed verifying the presence of Mycobacterium chelonae. Clarithromycin was continued and the doxycycline was replaced with oral trimethoprim-sulfamethoxazole (double strength) twice daily due to resistance. The patient was referred to an infectious disease specialist who concurred with the treatment regimen for a duration of 6 months to a year. A chest radiograph also was performed to rule out disseminated disease. Several months later the patient’s close friend presented with a similar infection that was acquired on the same day as our patient at the same tattoo parlor. The New York City Department of Health and Mental Hygiene was notified about these cases and informed us of other cases in New York State linked to contaminated tattoo ink.

Figure 1. Granulomatous collections of epithelioid histiocytes with neutrophilic and lymphocytic infiltrates in the dermis (H&E, original magnification ×4). Figure 2. Acid-fast organisms in the dermis (Fite, original magnification ×100).

Mycobacterium chelonae is a rapidly growing nontuberculous mycobacteria (Runyon group IV) that is found in nature and contaminated sources such as soil, lakes, sewage, and tap water.¹ Inoculation ofM chelonae through contaminated instruments leads to the formation of painful lesions, abscesses, fistulas, and granulomas that are extremely difficult to treat.² In our patient, M chelonae was most likely transmitted via contaminated tap water that was used to dilute the black tattoo ink to yield a gray color. Alternative sources are the ink itself or the container used to mix the ink.³Mycobacterium chelonae can cause infections in the skin, lungs, joints, bones, and eyes.⁴ With the exception of lung disease, trauma is the usual inciting factor. Disseminated infections are almost exclusively found in immunosuppressed individuals. Mycobacterium chelonae is typically found to grow on culture within 7 days. However, in our case there was no growth after 6 weeks of incubation. High-performance liquid chromatography analysis of mycolic acid is an alternative method of identifying mycobacteria. This technique verified the presence of M chelonae in our case when cultures were persistently negative.⁵

Mycobacterium chelonae is difficult to treat. The most common antibiotics used for treatment are clarithromycin, azithromycin, doxycycline, and linezolid.⁶ Studies of various antibiotics have shown that clarithromycin is the most effective macrolide against M chelonae.⁷ Tetracyclines also were studied in their effectiveness at treating nontuberculous mycobacteria infections but were found to have increased resistance to M chelonae.⁸ Although treatment regimens vary, the highest success rates are achieved with a minimum of 6 months of therapy using at least 2 drugs. Longer treatment is recommended for immunocompromised individuals.⁹

The case we present is important from a public health perspective. The tattoo industry and ink manufacturers should bemade aware of the risks of various infections from nonsterile techniques. Tattoo parlor employees should be advised of the risks of using nonsterile water for ink dilution and cleaning tattoo equipment. They also should be continuously educated on aseptic techniques.

The Diagnosis: Lichen Spinulosus

Lichen spinulosus, also referred to as keratosis spinulosa, is a disorder of keratinization characterized by grouped 1- to 3-mm papules with a horny spine localized to follicles (Figure).¹ These lesions most commonly occur in the first through third decades of life, presenting as 2- to 6-cm patches on the neck, buttocks, thighs, abdomen, or extensor surfaces.^1-4 Some patients report mild pruritus.¹ The cause is unknown.^1-3,5-7 Several proposed but unproven explanations include atopy,^2,4 genetic predisposition,^1,2 toxins,^3,5 infection,⁵ abnormal immune response,⁸ and vitamin deficiency.^1,6,7

Hyperkeratotic follicular “spines” localized to the right lower leg.

Our patient’s presentation is atypical due to her age and the involvement of her face. Generalized lichen spinulosus in adults likely is rare. A few similar cases have been reported: a 61-year-old woman with Crohn disease and lichen spinulosus affecting the groin, inframammary region, and back⁸; 2 case reports linked to alcoholism-associated nutritional deficiency^6,7; and generalized lichen spinulosus–like eruptions  in 2 patients with human immuno-deficiency virus infection.^9,10 Our patient’s medical history  indicated an extensive smoking history; thiamine deficiency 5 years prior treated with vitamin B complex supplements, which she still takes; and a recent diagnosis of vitamin D deficiency. She had no evidence of immunodeficiency or systemic illness on routine screening.

The disorders of follicular keratinization are lichen spinulosus, keratosis pilaris, keratosis pilaris atrophicans, pityriasis rubra pilaris, lichen planopilaris, erythromelanosis follicularis faciei, and phrynoderma.¹¹ The clinical differential diagnosis of lichen spinulosus includes keratosis pilaris, phrynoderma, pityriasis rubra pilaris, and frictional lichenoid eruption. Lichen spinulosus can be distinguished from keratosis pilaris by 4 factors^1,11: (1) keratosis pilaris lesions develop slowly over time as opposed to the rapid onset in lichen spinulosus; (2) keratosis pilaris is preferentially located on the upper arms and legs; (3) keratosis pilaris does not develop in small clusters; (4) keratosis pilaris, unlike lichen spinulosus, often has a thin outline of perifollicular erythema. Histopathologically, lichen spinulosus is similar to keratosis pilaris, showing dilated hair follicles with a keratin plug and perifollicular and perivascular dermal lymphocytic infiltrate.¹ A punch biopsy from our patient’s cheek demonstrated focal follicular hyperkeratosis with dermal perivascular inflammation. Periodic acid–Schiff with diastase stain was negative for pathogenic fungal organisms.

Treatment of lichen spinulosus is initiated to address cosmetic concerns. Traditionally, keratolytics and emollients are utilized. Success has been described with salicylic acid gel 6% without occlusion for 8 weeks¹² or with occlusion for 2 weeks.¹³ Tar preparations and mid-potency topical corticosteroids may be used on lesions not located on the face.^2,4,15 Topical vitamin A,² lactic acid,⁴ and ammonium lactate lotion² have been therapeutic in some cases. Facial lesions have been successfully treated with tacalcitol¹⁴ or tretinoin gel 0.04% in combination with hydroactive adhesive applications.¹⁵ In the case of lichen spinulosus accompanying alcoholism, oral vitamin supplementation has been sufficient for resolution.^6,7

Our patient was initially prescribed ammonium lactate lotion twice daily and tretinoin cream 0.025% for facial application nightly. She only used the tretinoin briefly due to skin irritation, and she discontinued use of ammonium lactate due to lotion texture. Three months of vitamin A and vitamin B complex supplementation did not lead to any improvement. She believed the papules softened by scrubbing them with a loofah in the shower and then moisturizing. Malignancy workup, including a colonoscopy, mammography, chest radiograph, and basic blood tests, were negative. No remarkable change was noted by the patient at 1-year follow-up.

The Diagnosis: Lichen Spinulosus

Lichen spinulosus, also referred to as keratosis spinulosa, is a disorder of keratinization characterized by grouped 1- to 3-mm papules with a horny spine localized to follicles (Figure).¹ These lesions most commonly occur in the first through third decades of life, presenting as 2- to 6-cm patches on the neck, buttocks, thighs, abdomen, or extensor surfaces.^1-4 Some patients report mild pruritus.¹ The cause is unknown.^1-3,5-7 Several proposed but unproven explanations include atopy,^2,4 genetic predisposition,^1,2 toxins,^3,5 infection,⁵ abnormal immune response,⁸ and vitamin deficiency.^1,6,7

Hyperkeratotic follicular “spines” localized to the right lower leg.

Our patient’s presentation is atypical due to her age and the involvement of her face. Generalized lichen spinulosus in adults likely is rare. A few similar cases have been reported: a 61-year-old woman with Crohn disease and lichen spinulosus affecting the groin, inframammary region, and back⁸; 2 case reports linked to alcoholism-associated nutritional deficiency^6,7; and generalized lichen spinulosus–like eruptions  in 2 patients with human immuno-deficiency virus infection.^9,10 Our patient’s medical history  indicated an extensive smoking history; thiamine deficiency 5 years prior treated with vitamin B complex supplements, which she still takes; and a recent diagnosis of vitamin D deficiency. She had no evidence of immunodeficiency or systemic illness on routine screening.

The disorders of follicular keratinization are lichen spinulosus, keratosis pilaris, keratosis pilaris atrophicans, pityriasis rubra pilaris, lichen planopilaris, erythromelanosis follicularis faciei, and phrynoderma.¹¹ The clinical differential diagnosis of lichen spinulosus includes keratosis pilaris, phrynoderma, pityriasis rubra pilaris, and frictional lichenoid eruption. Lichen spinulosus can be distinguished from keratosis pilaris by 4 factors^1,11: (1) keratosis pilaris lesions develop slowly over time as opposed to the rapid onset in lichen spinulosus; (2) keratosis pilaris is preferentially located on the upper arms and legs; (3) keratosis pilaris does not develop in small clusters; (4) keratosis pilaris, unlike lichen spinulosus, often has a thin outline of perifollicular erythema. Histopathologically, lichen spinulosus is similar to keratosis pilaris, showing dilated hair follicles with a keratin plug and perifollicular and perivascular dermal lymphocytic infiltrate.¹ A punch biopsy from our patient’s cheek demonstrated focal follicular hyperkeratosis with dermal perivascular inflammation. Periodic acid–Schiff with diastase stain was negative for pathogenic fungal organisms.

Treatment of lichen spinulosus is initiated to address cosmetic concerns. Traditionally, keratolytics and emollients are utilized. Success has been described with salicylic acid gel 6% without occlusion for 8 weeks¹² or with occlusion for 2 weeks.¹³ Tar preparations and mid-potency topical corticosteroids may be used on lesions not located on the face.^2,4,15 Topical vitamin A,² lactic acid,⁴ and ammonium lactate lotion² have been therapeutic in some cases. Facial lesions have been successfully treated with tacalcitol¹⁴ or tretinoin gel 0.04% in combination with hydroactive adhesive applications.¹⁵ In the case of lichen spinulosus accompanying alcoholism, oral vitamin supplementation has been sufficient for resolution.^6,7

Our patient was initially prescribed ammonium lactate lotion twice daily and tretinoin cream 0.025% for facial application nightly. She only used the tretinoin briefly due to skin irritation, and she discontinued use of ammonium lactate due to lotion texture. Three months of vitamin A and vitamin B complex supplementation did not lead to any improvement. She believed the papules softened by scrubbing them with a loofah in the shower and then moisturizing. Malignancy workup, including a colonoscopy, mammography, chest radiograph, and basic blood tests, were negative. No remarkable change was noted by the patient at 1-year follow-up.

The Diagnosis: Lichen Spinulosus

Lichen spinulosus, also referred to as keratosis spinulosa, is a disorder of keratinization characterized by grouped 1- to 3-mm papules with a horny spine localized to follicles (Figure).¹ These lesions most commonly occur in the first through third decades of life, presenting as 2- to 6-cm patches on the neck, buttocks, thighs, abdomen, or extensor surfaces.^1-4 Some patients report mild pruritus.¹ The cause is unknown.^1-3,5-7 Several proposed but unproven explanations include atopy,^2,4 genetic predisposition,^1,2 toxins,^3,5 infection,⁵ abnormal immune response,⁸ and vitamin deficiency.^1,6,7

Hyperkeratotic follicular “spines” localized to the right lower leg.

Our patient’s presentation is atypical due to her age and the involvement of her face. Generalized lichen spinulosus in adults likely is rare. A few similar cases have been reported: a 61-year-old woman with Crohn disease and lichen spinulosus affecting the groin, inframammary region, and back⁸; 2 case reports linked to alcoholism-associated nutritional deficiency^6,7; and generalized lichen spinulosus–like eruptions  in 2 patients with human immuno-deficiency virus infection.^9,10 Our patient’s medical history  indicated an extensive smoking history; thiamine deficiency 5 years prior treated with vitamin B complex supplements, which she still takes; and a recent diagnosis of vitamin D deficiency. She had no evidence of immunodeficiency or systemic illness on routine screening.

The disorders of follicular keratinization are lichen spinulosus, keratosis pilaris, keratosis pilaris atrophicans, pityriasis rubra pilaris, lichen planopilaris, erythromelanosis follicularis faciei, and phrynoderma.¹¹ The clinical differential diagnosis of lichen spinulosus includes keratosis pilaris, phrynoderma, pityriasis rubra pilaris, and frictional lichenoid eruption. Lichen spinulosus can be distinguished from keratosis pilaris by 4 factors^1,11: (1) keratosis pilaris lesions develop slowly over time as opposed to the rapid onset in lichen spinulosus; (2) keratosis pilaris is preferentially located on the upper arms and legs; (3) keratosis pilaris does not develop in small clusters; (4) keratosis pilaris, unlike lichen spinulosus, often has a thin outline of perifollicular erythema. Histopathologically, lichen spinulosus is similar to keratosis pilaris, showing dilated hair follicles with a keratin plug and perifollicular and perivascular dermal lymphocytic infiltrate.¹ A punch biopsy from our patient’s cheek demonstrated focal follicular hyperkeratosis with dermal perivascular inflammation. Periodic acid–Schiff with diastase stain was negative for pathogenic fungal organisms.

Treatment of lichen spinulosus is initiated to address cosmetic concerns. Traditionally, keratolytics and emollients are utilized. Success has been described with salicylic acid gel 6% without occlusion for 8 weeks¹² or with occlusion for 2 weeks.¹³ Tar preparations and mid-potency topical corticosteroids may be used on lesions not located on the face.^2,4,15 Topical vitamin A,² lactic acid,⁴ and ammonium lactate lotion² have been therapeutic in some cases. Facial lesions have been successfully treated with tacalcitol¹⁴ or tretinoin gel 0.04% in combination with hydroactive adhesive applications.¹⁵ In the case of lichen spinulosus accompanying alcoholism, oral vitamin supplementation has been sufficient for resolution.^6,7

Our patient was initially prescribed ammonium lactate lotion twice daily and tretinoin cream 0.025% for facial application nightly. She only used the tretinoin briefly due to skin irritation, and she discontinued use of ammonium lactate due to lotion texture. Three months of vitamin A and vitamin B complex supplementation did not lead to any improvement. She believed the papules softened by scrubbing them with a loofah in the shower and then moisturizing. Malignancy workup, including a colonoscopy, mammography, chest radiograph, and basic blood tests, were negative. No remarkable change was noted by the patient at 1-year follow-up.

The Diagnosis: Subungual Eccrine Poroma

Histologic examination revealed a solitary papule (Figure 1). The epidermis was replaced with a well-defined proliferation of cuboidal and poroid cells. These cells demonstrated a downgrowth into the dermis in broad anastomosing bands that were surrounded by a fibrovascular stroma. Notably, there were few scattered foci of maturation into the ductal lumina of eccrine origin, which confirmed the diagnosis (Figure 2).

Figure 1. A solitary papule consisting of a proliferation of cuboidal and poroid cells (H&E, original magnification ×4). Figure 2. Scattered foci of maturation into the ductal lumina of eccrine origin (H&E, original magnification ×10).

First described in 1956 by Goldman et al,¹ eccrine poromas are benign, slow-growing tumors that account for approximately 10% of sweat gland neoplasms.² Onset is typically in mid to late adulthood, and there is no ethnic or gender predilection. Classically, eccrine poromas present as soft, sessile, reddish papules or nodules measuring less than 2 cm that protrude from a well-circumscribed depression.

Although eccrine poromas can develop on hair-bearing regions, they most commonly arise on acral skin. In acral locations, bleeding, discharge, rapid growth, and localized pain can occur. These symptoms are even more common in this lesion’s malignant counterpart, eccrine porocarcinoma.³

Solar damage, radiation exposure, trauma, and human papillomavirus have been indicated in the pathogenesis of eccrine poroma; however, the exact etiology has yet to be defined.^2,4 The differential diagnosis includes nevus, pyogenic granu-loma, acrochordon, basal cell carcinoma, and verruca vulgaris.⁵

Histologically, eccrine poromas consist of a combination of 5 distinct features: poroid cells, cuticular cells, intracytoplasmic or intercellular vacuolization en route to duct formation, massive necrosis or necrosis en masse, and nuclear monomorphism of the poroid and cuticular cells.⁶ However, all 5 histologic features do not have to be present for the diagnosis. Classically, there is a sharp demarcation of the lesion from the surrounding epidermis.⁷

Treatment of choice is complete excision to prevent recurrence and risk for malignant transformation in long-standing lesions. One study of eccrine porocarcinomas found that 18% (11/62) arose from a benign preexistent poroma.⁸ These malignant lesions are found more commonly on the extremities and tend to show a slight female predominance.⁹

Although there have been 2 reported cases of subungual eccrine porocarcinomas^9,10 and 1 case of periungual eccrine porocarcinoma,¹¹ according to an Ovid search using the terms porocarcinoma and nail, the benign subungual eccrine poroma is more rare.

The Diagnosis: Subungual Eccrine Poroma

Histologic examination revealed a solitary papule (Figure 1). The epidermis was replaced with a well-defined proliferation of cuboidal and poroid cells. These cells demonstrated a downgrowth into the dermis in broad anastomosing bands that were surrounded by a fibrovascular stroma. Notably, there were few scattered foci of maturation into the ductal lumina of eccrine origin, which confirmed the diagnosis (Figure 2).

Figure 1. A solitary papule consisting of a proliferation of cuboidal and poroid cells (H&E, original magnification ×4). Figure 2. Scattered foci of maturation into the ductal lumina of eccrine origin (H&E, original magnification ×10).

First described in 1956 by Goldman et al,¹ eccrine poromas are benign, slow-growing tumors that account for approximately 10% of sweat gland neoplasms.² Onset is typically in mid to late adulthood, and there is no ethnic or gender predilection. Classically, eccrine poromas present as soft, sessile, reddish papules or nodules measuring less than 2 cm that protrude from a well-circumscribed depression.

Although eccrine poromas can develop on hair-bearing regions, they most commonly arise on acral skin. In acral locations, bleeding, discharge, rapid growth, and localized pain can occur. These symptoms are even more common in this lesion’s malignant counterpart, eccrine porocarcinoma.³

Solar damage, radiation exposure, trauma, and human papillomavirus have been indicated in the pathogenesis of eccrine poroma; however, the exact etiology has yet to be defined.^2,4 The differential diagnosis includes nevus, pyogenic granu-loma, acrochordon, basal cell carcinoma, and verruca vulgaris.⁵

Histologically, eccrine poromas consist of a combination of 5 distinct features: poroid cells, cuticular cells, intracytoplasmic or intercellular vacuolization en route to duct formation, massive necrosis or necrosis en masse, and nuclear monomorphism of the poroid and cuticular cells.⁶ However, all 5 histologic features do not have to be present for the diagnosis. Classically, there is a sharp demarcation of the lesion from the surrounding epidermis.⁷

Treatment of choice is complete excision to prevent recurrence and risk for malignant transformation in long-standing lesions. One study of eccrine porocarcinomas found that 18% (11/62) arose from a benign preexistent poroma.⁸ These malignant lesions are found more commonly on the extremities and tend to show a slight female predominance.⁹

Although there have been 2 reported cases of subungual eccrine porocarcinomas^9,10 and 1 case of periungual eccrine porocarcinoma,¹¹ according to an Ovid search using the terms porocarcinoma and nail, the benign subungual eccrine poroma is more rare.

The Diagnosis: Subungual Eccrine Poroma

Histologic examination revealed a solitary papule (Figure 1). The epidermis was replaced with a well-defined proliferation of cuboidal and poroid cells. These cells demonstrated a downgrowth into the dermis in broad anastomosing bands that were surrounded by a fibrovascular stroma. Notably, there were few scattered foci of maturation into the ductal lumina of eccrine origin, which confirmed the diagnosis (Figure 2).

Figure 1. A solitary papule consisting of a proliferation of cuboidal and poroid cells (H&E, original magnification ×4). Figure 2. Scattered foci of maturation into the ductal lumina of eccrine origin (H&E, original magnification ×10).

First described in 1956 by Goldman et al,¹ eccrine poromas are benign, slow-growing tumors that account for approximately 10% of sweat gland neoplasms.² Onset is typically in mid to late adulthood, and there is no ethnic or gender predilection. Classically, eccrine poromas present as soft, sessile, reddish papules or nodules measuring less than 2 cm that protrude from a well-circumscribed depression.

Although eccrine poromas can develop on hair-bearing regions, they most commonly arise on acral skin. In acral locations, bleeding, discharge, rapid growth, and localized pain can occur. These symptoms are even more common in this lesion’s malignant counterpart, eccrine porocarcinoma.³

Solar damage, radiation exposure, trauma, and human papillomavirus have been indicated in the pathogenesis of eccrine poroma; however, the exact etiology has yet to be defined.^2,4 The differential diagnosis includes nevus, pyogenic granu-loma, acrochordon, basal cell carcinoma, and verruca vulgaris.⁵

Histologically, eccrine poromas consist of a combination of 5 distinct features: poroid cells, cuticular cells, intracytoplasmic or intercellular vacuolization en route to duct formation, massive necrosis or necrosis en masse, and nuclear monomorphism of the poroid and cuticular cells.⁶ However, all 5 histologic features do not have to be present for the diagnosis. Classically, there is a sharp demarcation of the lesion from the surrounding epidermis.⁷

Treatment of choice is complete excision to prevent recurrence and risk for malignant transformation in long-standing lesions. One study of eccrine porocarcinomas found that 18% (11/62) arose from a benign preexistent poroma.⁸ These malignant lesions are found more commonly on the extremities and tend to show a slight female predominance.⁹

Although there have been 2 reported cases of subungual eccrine porocarcinomas^9,10 and 1 case of periungual eccrine porocarcinoma,¹¹ according to an Ovid search using the terms porocarcinoma and nail, the benign subungual eccrine poroma is more rare.

A 37-year-old pregnant woman at 25 weeks’ gestation presented with a generalized pruritic rash of 3 weeks’ duration. The rash had initiated around the umbilicus and continued to progress with subsequent involvement of the arms and legs. The patient reported no allergies or current medications, and her personal and family history was unremarkable. She had 2 prior uncomplicated pregnancies and deliveries. Physical examination revealed severe ecchymotic plaques, vesicles, and bullae on the arms (top), as well as confluent erythematous plaques on the abdomen (bottom), back, and legs. The mucosal surfaces, face, palms, and soles were spared. Laboratory values were within reference range.

The Diagnosis: Pemphigoid Gestationis (Herpes Gestationis)

Dermoscopy revealed a patch of erythema with early central vesiculation (Figure 1). Perilesional skin biopsies revealed subepidermal bullae, and direct immunofluorescence revealed linear C3 and IgG deposition at the dermoepidermal junction (Figure 2).

Figure 1. A patch of erythema with early central vesiculation. Figure 2. Direct immunofluorescence demonstrated the linear staining pattern of C3 deposition at the dermoepidermal junction (original magnification ×40).

Dermatoses of pregnancy are uncommon and may demonstrate similar clinical manifestations. Pemphigoid gestationis (herpes gestationis) is a condition that may initially mimic other pregnancy-related skin diseases but is followed by the classic manifestations of a bullous disease. A biopsy specimen is needed to identify the epidermal lesions that are present. Once identified, it responds to treatment with steroids.

Pemphigoid gestationis is a skin disorder in which circulating IgG autoantibodies react against transmembrane proteins and hemidesmosomal components of the epidermal basal cells.¹ This process leads to complement protein activation through the classical pathway, which promotes leukocyte recruitment and degranulation. The initial clinical manifestation includes pruritus, which is followed by characteristic bullous lesions.

Pemphigoid gestationis is hypothesized to arise from pathologic maternal IgG induced by paternal HLA antigens found in the placenta.² The incidence of pemphigoid gestationis is thought to range from 1:10,000 to 1:50,000,³ with typical presentation in the second or third trimesters. It may be exacerbated during delivery and generally resolves after delivery. The periumbilical region is the first site affected with subsequent spreading to the arms and legs.³ The initial differential diagnosis based on patient history can include an adverse drug reaction or pruritic urticarial papules and pustules of pregnancy. Diagnosis is based on histologic examination of a perilesional skin biopsy. Light microscopy of the biopsy typically reveals subepidermal bullae with a predominance of infiltrated eosinophils. Direct immunofluorescence of the biopsy specimen usually confirms the diagnosis with the presence of linear C3 and IgG deposition at the dermoepidermal junction. Indirect immunofluorescence occasionally may reveal IgG deposition in the basal membrane.⁴

Treatment generally includes the use of topical and oral steroids.^2,5 Fetal risks associated with the disease include premature birth and low birth weight.^2,3 Our patient initially was started on a 1-mg/kg dose of oral prednisone and topical steroid (prednisone 60 mg in a tapering dose every 5 days); she showed a good response at 1-week follow-up. She was well controlled with a lower maintenance dose through the rest of the pregnancy and did not show subsequent disease exacerbation.

A 37-year-old pregnant woman at 25 weeks’ gestation presented with a generalized pruritic rash of 3 weeks’ duration. The rash had initiated around the umbilicus and continued to progress with subsequent involvement of the arms and legs. The patient reported no allergies or current medications, and her personal and family history was unremarkable. She had 2 prior uncomplicated pregnancies and deliveries. Physical examination revealed severe ecchymotic plaques, vesicles, and bullae on the arms (top), as well as confluent erythematous plaques on the abdomen (bottom), back, and legs. The mucosal surfaces, face, palms, and soles were spared. Laboratory values were within reference range.

The Diagnosis: Pemphigoid Gestationis (Herpes Gestationis)

Dermoscopy revealed a patch of erythema with early central vesiculation (Figure 1). Perilesional skin biopsies revealed subepidermal bullae, and direct immunofluorescence revealed linear C3 and IgG deposition at the dermoepidermal junction (Figure 2).

Figure 1. A patch of erythema with early central vesiculation. Figure 2. Direct immunofluorescence demonstrated the linear staining pattern of C3 deposition at the dermoepidermal junction (original magnification ×40).

Dermatoses of pregnancy are uncommon and may demonstrate similar clinical manifestations. Pemphigoid gestationis (herpes gestationis) is a condition that may initially mimic other pregnancy-related skin diseases but is followed by the classic manifestations of a bullous disease. A biopsy specimen is needed to identify the epidermal lesions that are present. Once identified, it responds to treatment with steroids.

Pemphigoid gestationis is a skin disorder in which circulating IgG autoantibodies react against transmembrane proteins and hemidesmosomal components of the epidermal basal cells.¹ This process leads to complement protein activation through the classical pathway, which promotes leukocyte recruitment and degranulation. The initial clinical manifestation includes pruritus, which is followed by characteristic bullous lesions.

Pemphigoid gestationis is hypothesized to arise from pathologic maternal IgG induced by paternal HLA antigens found in the placenta.² The incidence of pemphigoid gestationis is thought to range from 1:10,000 to 1:50,000,³ with typical presentation in the second or third trimesters. It may be exacerbated during delivery and generally resolves after delivery. The periumbilical region is the first site affected with subsequent spreading to the arms and legs.³ The initial differential diagnosis based on patient history can include an adverse drug reaction or pruritic urticarial papules and pustules of pregnancy. Diagnosis is based on histologic examination of a perilesional skin biopsy. Light microscopy of the biopsy typically reveals subepidermal bullae with a predominance of infiltrated eosinophils. Direct immunofluorescence of the biopsy specimen usually confirms the diagnosis with the presence of linear C3 and IgG deposition at the dermoepidermal junction. Indirect immunofluorescence occasionally may reveal IgG deposition in the basal membrane.⁴

Treatment generally includes the use of topical and oral steroids.^2,5 Fetal risks associated with the disease include premature birth and low birth weight.^2,3 Our patient initially was started on a 1-mg/kg dose of oral prednisone and topical steroid (prednisone 60 mg in a tapering dose every 5 days); she showed a good response at 1-week follow-up. She was well controlled with a lower maintenance dose through the rest of the pregnancy and did not show subsequent disease exacerbation.

A 37-year-old pregnant woman at 25 weeks’ gestation presented with a generalized pruritic rash of 3 weeks’ duration. The rash had initiated around the umbilicus and continued to progress with subsequent involvement of the arms and legs. The patient reported no allergies or current medications, and her personal and family history was unremarkable. She had 2 prior uncomplicated pregnancies and deliveries. Physical examination revealed severe ecchymotic plaques, vesicles, and bullae on the arms (top), as well as confluent erythematous plaques on the abdomen (bottom), back, and legs. The mucosal surfaces, face, palms, and soles were spared. Laboratory values were within reference range.

The Diagnosis: Pemphigoid Gestationis (Herpes Gestationis)

Dermoscopy revealed a patch of erythema with early central vesiculation (Figure 1). Perilesional skin biopsies revealed subepidermal bullae, and direct immunofluorescence revealed linear C3 and IgG deposition at the dermoepidermal junction (Figure 2).

Figure 1. A patch of erythema with early central vesiculation. Figure 2. Direct immunofluorescence demonstrated the linear staining pattern of C3 deposition at the dermoepidermal junction (original magnification ×40).

Dermatoses of pregnancy are uncommon and may demonstrate similar clinical manifestations. Pemphigoid gestationis (herpes gestationis) is a condition that may initially mimic other pregnancy-related skin diseases but is followed by the classic manifestations of a bullous disease. A biopsy specimen is needed to identify the epidermal lesions that are present. Once identified, it responds to treatment with steroids.

Pemphigoid gestationis is a skin disorder in which circulating IgG autoantibodies react against transmembrane proteins and hemidesmosomal components of the epidermal basal cells.¹ This process leads to complement protein activation through the classical pathway, which promotes leukocyte recruitment and degranulation. The initial clinical manifestation includes pruritus, which is followed by characteristic bullous lesions.

Pemphigoid gestationis is hypothesized to arise from pathologic maternal IgG induced by paternal HLA antigens found in the placenta.² The incidence of pemphigoid gestationis is thought to range from 1:10,000 to 1:50,000,³ with typical presentation in the second or third trimesters. It may be exacerbated during delivery and generally resolves after delivery. The periumbilical region is the first site affected with subsequent spreading to the arms and legs.³ The initial differential diagnosis based on patient history can include an adverse drug reaction or pruritic urticarial papules and pustules of pregnancy. Diagnosis is based on histologic examination of a perilesional skin biopsy. Light microscopy of the biopsy typically reveals subepidermal bullae with a predominance of infiltrated eosinophils. Direct immunofluorescence of the biopsy specimen usually confirms the diagnosis with the presence of linear C3 and IgG deposition at the dermoepidermal junction. Indirect immunofluorescence occasionally may reveal IgG deposition in the basal membrane.⁴

Treatment generally includes the use of topical and oral steroids.^2,5 Fetal risks associated with the disease include premature birth and low birth weight.^2,3 Our patient initially was started on a 1-mg/kg dose of oral prednisone and topical steroid (prednisone 60 mg in a tapering dose every 5 days); she showed a good response at 1-week follow-up. She was well controlled with a lower maintenance dose through the rest of the pregnancy and did not show subsequent disease exacerbation.

The Diagnosis: “Pseudonits”

Dreadlocks are matted hairs formed into thick ropelike strands (Figure 1). As a chosen hairstyle dreadlocks are worn by individuals of many different ethnic groups but are most commonly associated with members of the Rastafarian movement, or Rastas. Various techniques are used to form dreadlocks including backcombing (also known as teasing) in which the hair is combed toward the scalp to facilitate tangles and knotting or the neglect method in which the hair is not combed, brushed, or cut, becoming tangled and twisted as it grows long. Manicuring and perming techniques may be used to create the starting point for dreadlocks.

Figure 1. Dreadlocks are matted hairs formed into thick ropelike strands.

Telogen hairs are the hairs shed as part of normal hair cycling. The average person is estimated to lose 50 telogen hairs per day.¹ With dreadlocks, the hairs are entangled distally, so when telogen hairs are released from scalp follicles, the shed hairs remain part of the locks. These “club” hairs have a bulbous white tip situated at the proximal end of the hair shaft (Figure 2) and should not be mistaken for the eggs of Pediculus humanus var capitis, hence the designation pseudonits.² Hair casts, keratinous material surrounding the hair shafts when there is infundibular or perifollicular hyperkeratosis, also may resemble nits.³ Hair cast pseudonits can be distinguished from true nits by one’s ability to slide the hair casts freely along the hair shaft, whereas lice ova are cemented to the hair shaft and fixed in place.

The Diagnosis: “Pseudonits”

Dreadlocks are matted hairs formed into thick ropelike strands (Figure 1). As a chosen hairstyle dreadlocks are worn by individuals of many different ethnic groups but are most commonly associated with members of the Rastafarian movement, or Rastas. Various techniques are used to form dreadlocks including backcombing (also known as teasing) in which the hair is combed toward the scalp to facilitate tangles and knotting or the neglect method in which the hair is not combed, brushed, or cut, becoming tangled and twisted as it grows long. Manicuring and perming techniques may be used to create the starting point for dreadlocks.

Figure 1. Dreadlocks are matted hairs formed into thick ropelike strands.

Telogen hairs are the hairs shed as part of normal hair cycling. The average person is estimated to lose 50 telogen hairs per day.¹ With dreadlocks, the hairs are entangled distally, so when telogen hairs are released from scalp follicles, the shed hairs remain part of the locks. These “club” hairs have a bulbous white tip situated at the proximal end of the hair shaft (Figure 2) and should not be mistaken for the eggs of Pediculus humanus var capitis, hence the designation pseudonits.² Hair casts, keratinous material surrounding the hair shafts when there is infundibular or perifollicular hyperkeratosis, also may resemble nits.³ Hair cast pseudonits can be distinguished from true nits by one’s ability to slide the hair casts freely along the hair shaft, whereas lice ova are cemented to the hair shaft and fixed in place.

The Diagnosis: “Pseudonits”

Dreadlocks are matted hairs formed into thick ropelike strands (Figure 1). As a chosen hairstyle dreadlocks are worn by individuals of many different ethnic groups but are most commonly associated with members of the Rastafarian movement, or Rastas. Various techniques are used to form dreadlocks including backcombing (also known as teasing) in which the hair is combed toward the scalp to facilitate tangles and knotting or the neglect method in which the hair is not combed, brushed, or cut, becoming tangled and twisted as it grows long. Manicuring and perming techniques may be used to create the starting point for dreadlocks.

Figure 1. Dreadlocks are matted hairs formed into thick ropelike strands.

Telogen hairs are the hairs shed as part of normal hair cycling. The average person is estimated to lose 50 telogen hairs per day.¹ With dreadlocks, the hairs are entangled distally, so when telogen hairs are released from scalp follicles, the shed hairs remain part of the locks. These “club” hairs have a bulbous white tip situated at the proximal end of the hair shaft (Figure 2) and should not be mistaken for the eggs of Pediculus humanus var capitis, hence the designation pseudonits.² Hair casts, keratinous material surrounding the hair shafts when there is infundibular or perifollicular hyperkeratosis, also may resemble nits.³ Hair cast pseudonits can be distinguished from true nits by one’s ability to slide the hair casts freely along the hair shaft, whereas lice ova are cemented to the hair shaft and fixed in place.

The Diagnosis: Infantile Digital Fibromatosis

On examination, the patient appeared well developed, well nourished, and had a 1×0.5-cm, flesh-colored, firm, nontender nodule on the dorsolateral aspect of the left second toe. After excision by a pediatric surgeon, the specimen was submitted for histopathologic examination. Dense bands of collagen with spindled myofibroblasts containing characteristic eosinophilic cytoplasmic inclusion bodies staining with phosphotungstic acid hematoxylin confirmed the diagnosis of infantile digital fibromatosis (Figure). Postoperatively the patient did well with normal healing and no complications. After 4 months, a recurrence was noted and the parents were considering reexcision.

Histopathology revealed a dense spindled cell proliferation in the dermis with low power (A)(H&E, original magnification ×4). High-power examination showed myofibroblasts with characteristic round and ovoid, eosinophilic, cytoplasmic inclusion bodies (B)(H&E, original magnification ×40). Inclusion bodies stained purple with phosphotungstic acid hematoxylin stain (C)(original magnification ×40).

Infantile digital fibromatosis is a rare, benign, often spontaneously regressing, fibrous tissue tumor of infancy and childhood.¹ The prevalence of this tumor is unknown. It can be present at birth or more commonly appears in the first year of life. The lesions present as 1- to 2-cm, firm, flesh-colored nodules that initially grow slowly but have the potential for rapid growth in subsequent months. They occur preferentially on the extensor aspects of the digits, typically sparing the thumb and great toe.¹ The clinical differential diagnosis includes keloids or hypertrophic scars, granuloma annulare, sarcoidosis, acral fibrokeratomas, periungual fibromas, supernumerary digits, pachydermodactyly, juvenile aponeurotic fibroma, and terminal osseous dysplasia and pigmentary defects.²

The histology of infantile digital fibromatosis is distinctive. Spindled myofibroblasts that contain round or ovoid, eosinophilic, cytoplasmic inclusion bodies composed of an accumulation of actin and vimentin filaments are characteristic.¹ Inclusions are typically juxtanuclear and may indent the adjacent nucleus. The inclusion bodies stain red with Masson trichrome stain and purple with phosphotungstic acid hematoxylin stain.¹ The histopathologic differential diagnosis includes scar, angiofibroma, dermatofibroma, neurofibroma, and angiofibromatous verruca vulgaris.

Although many treatments exist for infantile digital fibromatosis, optimal therapy is not standardized. Most lesions spontaneously regress, but func-tional disability with deforming contractures can occur if untreated. Topical therapy with imiquimod cream 5% and diflucortolone valerate cream have been reported to produce no effect on tumor size.³ Intralesional 5-fluorouracil was successful in treating a patient after 5 monthly injections.⁴ Intralesional triamcinolone 10 mg/cc injections were shown to be a well-tolerated and successful treatment in a case series of 7 patients.⁵ The most utilized intervention appears to be standard surgery, with a few patients treated with Mohs micrographic surgery.^6,7

Treatment with surgical excision often results in recurrence, with studies showing a 50% to 75% recurrence rate.^8,9 Our case is not atypical and illustrates this phenomenon. Other reported complications of surgical management include hypertrophic scarring and reduced distal interphalangeal joint mobility.⁵ Unless infantile digital fibromatosis causes mobility dysfunction or related disabilities, observation with regular follow-up should be considered, as lesions can spontaneously regress.

The Diagnosis: Infantile Digital Fibromatosis

On examination, the patient appeared well developed, well nourished, and had a 1×0.5-cm, flesh-colored, firm, nontender nodule on the dorsolateral aspect of the left second toe. After excision by a pediatric surgeon, the specimen was submitted for histopathologic examination. Dense bands of collagen with spindled myofibroblasts containing characteristic eosinophilic cytoplasmic inclusion bodies staining with phosphotungstic acid hematoxylin confirmed the diagnosis of infantile digital fibromatosis (Figure). Postoperatively the patient did well with normal healing and no complications. After 4 months, a recurrence was noted and the parents were considering reexcision.

Histopathology revealed a dense spindled cell proliferation in the dermis with low power (A)(H&E, original magnification ×4). High-power examination showed myofibroblasts with characteristic round and ovoid, eosinophilic, cytoplasmic inclusion bodies (B)(H&E, original magnification ×40). Inclusion bodies stained purple with phosphotungstic acid hematoxylin stain (C)(original magnification ×40).

Infantile digital fibromatosis is a rare, benign, often spontaneously regressing, fibrous tissue tumor of infancy and childhood.¹ The prevalence of this tumor is unknown. It can be present at birth or more commonly appears in the first year of life. The lesions present as 1- to 2-cm, firm, flesh-colored nodules that initially grow slowly but have the potential for rapid growth in subsequent months. They occur preferentially on the extensor aspects of the digits, typically sparing the thumb and great toe.¹ The clinical differential diagnosis includes keloids or hypertrophic scars, granuloma annulare, sarcoidosis, acral fibrokeratomas, periungual fibromas, supernumerary digits, pachydermodactyly, juvenile aponeurotic fibroma, and terminal osseous dysplasia and pigmentary defects.²

The histology of infantile digital fibromatosis is distinctive. Spindled myofibroblasts that contain round or ovoid, eosinophilic, cytoplasmic inclusion bodies composed of an accumulation of actin and vimentin filaments are characteristic.¹ Inclusions are typically juxtanuclear and may indent the adjacent nucleus. The inclusion bodies stain red with Masson trichrome stain and purple with phosphotungstic acid hematoxylin stain.¹ The histopathologic differential diagnosis includes scar, angiofibroma, dermatofibroma, neurofibroma, and angiofibromatous verruca vulgaris.

Although many treatments exist for infantile digital fibromatosis, optimal therapy is not standardized. Most lesions spontaneously regress, but func-tional disability with deforming contractures can occur if untreated. Topical therapy with imiquimod cream 5% and diflucortolone valerate cream have been reported to produce no effect on tumor size.³ Intralesional 5-fluorouracil was successful in treating a patient after 5 monthly injections.⁴ Intralesional triamcinolone 10 mg/cc injections were shown to be a well-tolerated and successful treatment in a case series of 7 patients.⁵ The most utilized intervention appears to be standard surgery, with a few patients treated with Mohs micrographic surgery.^6,7

Treatment with surgical excision often results in recurrence, with studies showing a 50% to 75% recurrence rate.^8,9 Our case is not atypical and illustrates this phenomenon. Other reported complications of surgical management include hypertrophic scarring and reduced distal interphalangeal joint mobility.⁵ Unless infantile digital fibromatosis causes mobility dysfunction or related disabilities, observation with regular follow-up should be considered, as lesions can spontaneously regress.

The Diagnosis: Infantile Digital Fibromatosis

On examination, the patient appeared well developed, well nourished, and had a 1×0.5-cm, flesh-colored, firm, nontender nodule on the dorsolateral aspect of the left second toe. After excision by a pediatric surgeon, the specimen was submitted for histopathologic examination. Dense bands of collagen with spindled myofibroblasts containing characteristic eosinophilic cytoplasmic inclusion bodies staining with phosphotungstic acid hematoxylin confirmed the diagnosis of infantile digital fibromatosis (Figure). Postoperatively the patient did well with normal healing and no complications. After 4 months, a recurrence was noted and the parents were considering reexcision.

Histopathology revealed a dense spindled cell proliferation in the dermis with low power (A)(H&E, original magnification ×4). High-power examination showed myofibroblasts with characteristic round and ovoid, eosinophilic, cytoplasmic inclusion bodies (B)(H&E, original magnification ×40). Inclusion bodies stained purple with phosphotungstic acid hematoxylin stain (C)(original magnification ×40).

Infantile digital fibromatosis is a rare, benign, often spontaneously regressing, fibrous tissue tumor of infancy and childhood.¹ The prevalence of this tumor is unknown. It can be present at birth or more commonly appears in the first year of life. The lesions present as 1- to 2-cm, firm, flesh-colored nodules that initially grow slowly but have the potential for rapid growth in subsequent months. They occur preferentially on the extensor aspects of the digits, typically sparing the thumb and great toe.¹ The clinical differential diagnosis includes keloids or hypertrophic scars, granuloma annulare, sarcoidosis, acral fibrokeratomas, periungual fibromas, supernumerary digits, pachydermodactyly, juvenile aponeurotic fibroma, and terminal osseous dysplasia and pigmentary defects.²

The histology of infantile digital fibromatosis is distinctive. Spindled myofibroblasts that contain round or ovoid, eosinophilic, cytoplasmic inclusion bodies composed of an accumulation of actin and vimentin filaments are characteristic.¹ Inclusions are typically juxtanuclear and may indent the adjacent nucleus. The inclusion bodies stain red with Masson trichrome stain and purple with phosphotungstic acid hematoxylin stain.¹ The histopathologic differential diagnosis includes scar, angiofibroma, dermatofibroma, neurofibroma, and angiofibromatous verruca vulgaris.

Although many treatments exist for infantile digital fibromatosis, optimal therapy is not standardized. Most lesions spontaneously regress, but func-tional disability with deforming contractures can occur if untreated. Topical therapy with imiquimod cream 5% and diflucortolone valerate cream have been reported to produce no effect on tumor size.³ Intralesional 5-fluorouracil was successful in treating a patient after 5 monthly injections.⁴ Intralesional triamcinolone 10 mg/cc injections were shown to be a well-tolerated and successful treatment in a case series of 7 patients.⁵ The most utilized intervention appears to be standard surgery, with a few patients treated with Mohs micrographic surgery.^6,7

Treatment with surgical excision often results in recurrence, with studies showing a 50% to 75% recurrence rate.^8,9 Our case is not atypical and illustrates this phenomenon. Other reported complications of surgical management include hypertrophic scarring and reduced distal interphalangeal joint mobility.⁵ Unless infantile digital fibromatosis causes mobility dysfunction or related disabilities, observation with regular follow-up should be considered, as lesions can spontaneously regress.