Extensive Spiculated Follicular Porokeratosis With Alopecia: A Case Report

ABSTRACTFollicular porokeratosis (FPK) is a rare subtype of porokeratosis. Follicular porokeratosis mainly occurs in men and may be localized or diffuse. Involvement of the scalp is rarely reported, and we found only one case of alopecia due to scalp FPK. Diabetes mellitus has not been reported in association with FPK We report a 35‐year‐old diabetic woman that presented with brown follicular keratotic papules and spicules involving the scalp, face, trunk, and extremities, accompanied by scalp alopecia. The differential diagnoses were lichen planopilaris, papular eczema, and phrynoderma. Histopathologic examination of skin punch biopsies revealed the follicle‐centered cornoid lamella as the feature of FPK. The patient was treated with oral isotretinoin, and the lesions improved partially within 6 weeks of follow‐up. Follicular porokeratosis might be considered among the differential diagnoses of keratotic papules (with or without spicules) and in the cases of alopecia with keratotic papules. Diabetes mellitus may be associated with FPK.