Nevus comedonicus of the scalp

A 10-year-old boy presented to us with a localized patch of hair loss on the scalp, first noticed by his mother a few months after birth. The lesion had shown very little increase in size since that time. There was a history of occasional redness and discharge from the lesion, which used to be controlled with topical applications. There was no history of any trauma to the site. There was no family history of any similar lesion or any associated systemic problems. On examination, grouped comedonal lesions were seen over a patch of partial alopecia located on the occipital area of the scalp (Figure 1). There was no evidence of inflammation. Systemic examination was normal. Biopsy specimen from the lesion on the scalp showed foci of wide and deep invaginations of the epidermis filled with keratin. There was no evidence of any significant perifollicular inflammatory infiltrate (Figure 2). A possibility of an atypical nevus comedonicus was considered. The patient was started on topical tretinoin 0.05% and is under follow-up.