REACTIVE PERFORATING COLLAGENOSIS - TRANSEPIDERMAL ELIMINATION OF TYPE-IV COLLAGEN

Reactive perforating collagenosis (RPC) is a rare skin disorder charac terized by reddish papules with a central keratotic plug which appear mainly on the extensor aspects of the limbs. An idiopathic or classica l variant has been delineated from an acquired one which occurs in dia betes mellitus and renal failure. Histopathological examination of the lesions shows transepidermal elimination of abnormally staining bundl es of collagen. To clarify the origin of this collagenous material we performed an immunohistochemical study including biopsies of two patie nts with RPC, one classical and one acquired. Staining reactivity to a ntibodies against type IV collagen was observed, thus providing eviden ce that the collagen eliminated in RPC may be derived from the basemen t membrane zone.