Bullous pemphigoid (BUL-us PEM-fih-goid) is a rare, persistent skin condition that usually appears as large, fluid-filled blisters (bullae) in your skin. Although anyone can develop bullous pemphigoid, it almost always affects older adults.

Bullous pemphigoid occurs when the immune system mounts an attack against a thin layer of tissue below your outer layer of skin. The reason for this abnormal immune response is unknown.

Drugs that suppress the immune system abnormalities of bullous pemphigoid improve symptoms, but they require careful monitoring for serious side effects. Bullous pemphigoid is rarely life-threatening, except in older individuals already in poor health or in people with otherwise poor immune system function.

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