Acquired reactive perforating collagenosis, a rare entity at uncommon site.

Acquired reactive perforating collagenosis (ARPC), rare disorder characterized by transepidermal elimination (TEE) of collagen fibers, is seen in adult diabetics. Genetic predisposition, familial aggregation, trauma, bites and scratching are implicated. Diabetics develop microvascular diseases leading to intense pruritus causing repeated micro trauma leading to necrosis of connective tissue of dermis, causing TEE.