Lichen spinulosus with immunofluorescent studies.

A typical case of lichen spinulosus in a 15-year-old boy is described. Keratotic papules and plaques occurred on the knees, elbows, and lower legs. A biopsy showed follicular hyperkeratosis consistent with lichen spinulosus. Studies for immunofluorescence demonstrated linear IgM at the basement membrane zone without colloid bodies. The relationship of lichen spinulosus and lichen planus is discussed. The patient responded to treatment with a salicylic acid gel.