Epidermolysis bullosa acquisita has been recognized as a rare autoimmune mechanobullous disorder since the detection of immunoglobulin and complement deposits along the basement membrane zone. A circulating anti-basement membrane zone antibody has also been detected in some cases. We are reporting a case of epidermolysis bullosa acquisita in which clinical symptoms were well correlated with the circulating anti-basement membrane zone antibody titers. Although the patient initially responded very well to corticosteroid therapy, remission could not be maintained without increasing the dosage. Other therapies, including azathioprine, dapsone, vitamin E, and gold sodium thiomalate, produced no beneficial effects. Although a high dose of oral corticosteroid and cyclophosphamide decreased the antibody titer and blister formation, this therapy had to be terminated because of side effects. Plasma exchange therapy in combination with corticosteroid and low-dose cyclophosphamide resulted in a marked decrease of the anti-basement membrane zone antibody titer and clinical improvement. Thus plasma exchange therapy may be a useful adjunct to conventional treatments for patients with epidermolysis bullosa acquisita.