Delineating the Perforating Dermatoses: Case Reports and a Review of the Literature

Perforating dermatoses (PD) represent a rare group of papulonodular skin diseases with a distinct central keratotic core. The core represents the transepidermal elimination of an altered dermal substance.1 Diagnosis is established via biopsy and histopathologic evaluation. Whereas primary PD are diseases chiefly characterized by transepidermal elimination, secondary PD are a group of unrelated disorders in which transepidermal elimination is a minor phenomenon of another disorder.1 The primary PD are best categorized into four groups: reactive perforating collagenosis (RPC), acquired perforating dermatosis (APD), elastosis perforans serpiginosa (EPS), and perforating calcific elastosis (PCE). The primary PD can be differentiated based on the perforating substance, the distribution of the lesions, and their unique associations (Table 1).1 Diagnosis of a PD should prompt screening for underlying systemic disease. Treatment of the PD is often difficult, but numerous reports have shown success.