Pemphigus is a group of chronic autoimmune skin diseases characterized by blister formations in the outer layer of the skin and the mucous membranes. Pemphigus vulgaris begins with blister formations (bullae) occurring in the mouth and on the scalp. The blisters are soft and are easily broken. The blistering can also affect the esophagus, rectum, nose or the lining of the eyelids. These bullae heal without scarring. Pemphigus vulgaris most often occurs in middle-aged patients of Jewish or Mediterranean descent. It has been associated with other autoimmune diseases such as myasthenia gravis and lupus. Diagnosis of an autoimmune bullous disease should be suspect when there is no clear history of exposure to a drug or a contact allergen or when other studies for infectious origins, such as herpes or impetigo, are negative. To differentiate these diseases, a careful history and physical examination are important. A skin biopsy is often helpful.