Please wait for the figures to download 1. 2. This is an uncommon papular and keratotic disorder of unknown etiology characterized by reddish-brown papules with a central keratotic plug present on the extensor surfaces of the extremities. The pathologic hallmark is penetration of a keratotic plug into the dermis. The clinical course is chronic. Response to treatment is variable and relapses after therapy is discontinued are common.
Topical therapy has little effect although it can give temporary relief.
Phototherapy gives temporary symptomatic relief but does not affect the course of the disease. There is densely packed degenerated basophilic material and altered basophilic collagen bundels are present. Fraga S. Reactive perforating collagenosis of diabetes mellitus. Journal of Dermatology. The pathogenesis of transepithelial elimination of the collagen bundles in acquired reactive perforating collagenosis.