PEMPHIGUS

a group of skin diseases characterized by large blisters that appear on the skin and mucous membranes. Pemphigus diseases include pemphigus vulgaris, pemphigus vegetans, pemphigus foliaceus, pemphigus erythematosus, and benign familial pemphigus. The most common and most severe of these diseases is pemphigus vulgaris, in which large, flaccid blisters erupt on otherwise healthy-looking skin and mucous membranes. The first site of blistering is often the mouth. The blisters rupture easily, leaving weeping, encrusted areas that do not heal. Pain from mouth lesions can prevent the individual from eating. If untreated, the disease can cause fluid and electrolyte imbalance, sepsis, and death. Pemphigus vegetans is similar. Both are autoimmune diseases caused by antibodies that are produced against proteins (antigens) found within cells of the outermost layer of the skin, called the epidermis. The interaction between autoantibodies and these antigens results in a loss of cohesion among skin cells and the degeneration of skin layers. The clefts and splits within the degenerating skin layers fill with fluid, leading to the characteristic blistering. These diseases can be successfully treated with immunosuppressive drugs and high doses of systemic corticosteroids. Pemphigus foliaceus and pemphigus erythematosus are less severe. Mucous membranes are rarely involved. Lesions may be found on the scalp, face, or trunk, or they may spread. They also arise from an autoimmune reaction, but the process usually occurs nearer the surface of the epidermis. Low doses of systemic steroids usually control them. Benign familial pemphigus, also called Hailey-Hailey disease, is an inherited disorder characterized by blisters on the neck, groin, and armpits. Unlike other forms of pemphigus, autoantibodies are not apparent. Topical and systemic antibiotics are used to treat flare-ups.