Bullous pemphigoid arising in a patient with acquired perforating dermatosis

A middle-aged Japanese man who had been on haemodialysis treatment for diabetic nephropathy developed multiple itchy papules and nodules, which were histopathologically diagnosed as acquired perforating dermatosis. Two years later he developed oral lesions and subsequently numerous erosive plaques with necrotic crusts on the trunk and extremities. Histopathology of a papule showed a parakeratotic plug intermingled with basophilic, necrotic debris and collagen bundles, along with penetration of collagen bundles across the epidermis and subepidermal blister. Immunoblotting studies revealed IgG autoantibodies in the patient's serum, which reacted with the C-terminal and the NC16a domains of bullous pemphigoid (BP)180, indicating presence of BP. We searched the literature and found no other cases of an autoimmune blistering disease occurring in association with a perforating disorder. Possible injury to the basement membrane zone induced during the process of transepidermal elimination might be involved in the pathogenesis of the pemphigoid disease.