Pemphigus vulgaris occurs when the immune system mistakenly attacks proteins in the upper layers of the skin.
People have severe blistering in the mouth and on other areas of the body, and sometimes sheets of skin peel off.
Doctors can diagnose pemphigus vulgaris by examining skin samples under a microscope.
Treatment usually involves corticosteroids or drugs that suppress the immune system.

Pemphigus develops most often in middle-aged or older people, affecting equal numbers of men and women. It rarely develops in children.
In this autoimmune disease, the immune system, which normally protects the body against foreign invaders, mistakenly attacks the body’s own cells—in this case, the skin. Antibodies produced by the immune system attack specific proteins that connect the epidermal cells (the cells in the top layer of skin) to each other. When these connections are disrupted, the cells separate from each other and from the lower layers of the skin, and blisters form. Similar-appearing blisters occur with a less dangerous skin disorder called bullous pemphigoid.
(See also Overview of Blistering Disorders.)