A case is presented of subepidermal, autoimmune bullous disease in which the initial examinations suggested the combination of epidermolysis bullosa acquisita and bullous pemphigoid. The diagnosis of epidermolysis bullosa acquisita was made by indirect immunofluorescence microscopy: the patient's serum bound to normal skin substrate but not to type VII collagen-deficient skin substrate derived from a patient with mutilating dystrophic epidermolysis bullosa. The use of skin substrates deficient in basement membrane molecules also excluded the presence of concomitant, circulating bullous pemphigoid autoantibodies in our patient. The diagnosis of epidermolysis bullosa acquisita was confirmed by split mapping, fluorescence overlay antigen mapping and Western blot.