Reactive Perforating Collagenosis.

Reactive perforating collagenosis (RPC) is a rare disease belonging to the spectrum of primary perforating dermatoses. It manifests clinically with brown-erythematous papules with a central plug that develop after minor skin trauma, and it is characterized histologically by epidermal perforation and transepidermal elimination of altered dermal collagen. Familial and acquired forms have been described, the latter usually associated with systemic diseases, among which diabetes mellitus and renal failure are the most common. A new case of RPC is presented here, along with an updated brief literature review on this unusual dermatosis.