Patients with autoimmune bullous diseases are occasionally encountered in primary care practice, usually in middle-aged and older patients. The differential diagnosis includes nonimmune causes, such as contact dermatitis, infections and bullous reactions to drugs or insect bites. An autoimmune blistering disease may be distinguished by the age of the patient when the disease first appears, the morphology and distribution of the lesions and the presence or absence of mucosal lesions and scarring. Because the clinical presentations of blistering disorders are often similar, special immunofluorescence tests are used to confirm the specific diagnosis. Since diagnosis and management of an autoimmune bullous disease may involve systems other than the skin, coordination by the primary care physician is crucial.