Lichen planopilaris and psoriasis.

A 34-year-old woman presented with large, scaly patches of alopecia with a peripheral rim of violaceous, folliculocentric papules and appreciable pruritus of one-year duration. Histopathologic examination showed changes consistent with lichen planopilaris and psoriasis, which was suggested by neutrophilic spongiosis. Consequently, cyclosporine and betamethasone valerate topical 0.12 percent foam twice daily were initiated. A short time after, there was clinical reduction of perifollicular erythema and attenuation of pruritus. However, there was no decrease of scale. Although LLP is classified in the lymphocytic group of cicatricial alopecias, this case demonstrates a clinical and histopathologic overlap with a psoriasiform dermatosis which may represent a collision of two diseases.