Acquired hypertrichosis localized on a subsiding psoriatic plaque after plaster application

Postcast hypertrichosis is a common transient occurrence in orthopedic patients and generally resolves within a few months. Until now, two cases of localized hypertrichosis occurring on more than one pre-existing psoriatic lesions are reported in the literature. We describe the case of a patient who simultaneously developed a single psoriatic plaque and overlying localized hypertrichosis after plaster application. This concurrence is exceptional and may be explained by the expression of several growth factors and cytokines influencing both the hair cycle and the psoriatic inflammatory working.