Bullous pemphigoid

Overview

Bullous pemphigoid (BUL-us PEM-fih-goid) is a rare skin condition that causes large, fluid-filled blisters. They develop on areas of skin that often flex — such as the lower abdomen, upper thighs or armpits. Bullous pemphigoid is most common in older adults.

Bullous pemphigoid occurs when your immune system attacks a thin layer of tissue below your outer layer of skin. The reason for this abnormal immune response is unknown, although it sometimes can be triggered by taking certain medications.

Bullous pemphigoid often goes away on its own in a few months, but may take as many as five years to resolve. Treatment usually helps heal the blisters and ease any itching. It may include corticosteroid medications, such as prednisone, and other drugs that suppress the immune system. Bullous pemphigoid can be life-threatening, especially for older people who are already in poor health.

Symptoms

The signs and symptoms of bullous pemphigoid may include:

• Itching skin, weeks or months before blisters form
• Large blisters that don't easily rupture when touched, often along creases or folds in the skin
• Skin around the blisters that is normal, reddish or darker than normal
• Eczema or a hive-like rash
• Small blisters or sores in the mouth or other mucous membranes (benign mucous membrane pemphigoid)

When to see a doctor

See your doctor if you develop:

• Unexplained blistering
• Blisters on your eyes
• Signs of infection

Causes

The blisters occur because of a malfunction in your immune system.

Your body's immune system normally produces antibodies to fight bacteria, viruses or other potentially harmful foreign substances. For reasons that are not clear, the body may develop an antibody to a particular tissue in your body.

In bullous pemphigoid, the immune system produces antibodies to the fibers that connect the outer layer of skin (epidermis) and the next layer of skin (dermis). These antibodies trigger inflammation that produces the blisters and itching of bullous pemphigoid.

Contributing factors

Bullous pemphigoid usually appears randomly with no clear factors contributing to the onset of disease. Some cases may be triggered by:

• Medications. Prescription drugs that may cause bullous pemphigoid include etanercept (Enbrel), sulfasalazine (Azulfidine), furosemide (Lasix) and penicillin.
• Light and radiation. Ultraviolet light therapy to treat certain skin conditions may trigger bullous pemphigoid, as can radiation therapy to treat cancer.
• Medical conditions. Disorders that may trigger bullous pemphigoid include psoriasis, lichen planus, diabetes, rheumatoid arthritis, ulcerative colitis and multiple sclerosis.

Risk factors

Bullous pemphigoid most commonly occurs in older adults, and the risk increases with age.