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.

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

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.

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

To confirm the diagnosis, your doctor may order blood tests and take a small sample of the affected skin (skin biopsy) for laboratory testing.

Your doctor may refer you to a doctor who specializes in conditions of the skin (dermatologist) or eyes (ophthalmologist), depending on your signs and symptoms and the results of your lab tests.

Treatment is focused on healing the skin and relieving itching, while minimizing adverse side effects of medications. Your doctor will likely prescribe one or a combination of the drugs:

• Corticosteroids. The most common treatment is prednisone, which comes in pill form. But long-term use can increase your risk of weak bones, diabetes, high blood pressure, high cholesterol and infection. Corticosteroid ointment can be rubbed on your affected skin and causes fewer side effects.
• Steroid-sparing drugs. These drugs affect the immune system by inhibiting the production of your body's disease-fighting white blood cells. Examples include azathioprine (Azasan, Imuran) and mycophenolate mofetil (CellCept). If your signs and symptoms involve the eyes or upper digestive tract, the drug rituximab (Rituxan) may be used if other approaches haven't helped.
• Other drugs that fight inflammation. An example is methotrexate (Trexall).

If you have bullous pemphigoid, you can help take care of your condition with the following self-care strategies:

• Wound care. Follow your doctor's advice for daily care of blisters.
• Limit activities if needed. Blisters on the feet and hands can make it difficult to walk or to go about daily activities. You may need to change your routine until the blisters are under control.
• Avoid sun exposure. Avoid prolonged sun exposure on any area of the skin affected by bullous pemphigoid.
• Dress in loosefitting cotton clothes. This helps protect your skin.
• Watch what you eat. If you have blisters in your mouth, avoid eating hard and crunchy foods, such as chips and raw fruits and vegetables, because these types of foods might aggravate symptoms.

You may start by seeing your primary care doctor. He or she may refer you to a doctor who specializes in skin disorders (dermatologist). You may want to bring a friend or relative to your appointment. This person, in addition to offering support, can write down information from your doctor or other clinic staff during the visit.

What you can do

Before your appointment make a list of:

• Symptoms you've been having and for how long
• The name and contact information of any doctor you have seen recently or see regularly
• All medications, vitamins and supplements you take, including doses
• Questions to ask your doctor

For bullous pemphigoid, some basic questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• Are there other possible causes?
• Do I need any tests?
• How long will these skin changes last?
• What treatments are available, and which do you recommend?
• What side effects can I expect from treatment?

What to expect from your doctor

Your doctor will likely ask you a number of questions. Be prepared to answer the following:

• When did these symptoms begin?
• Where are the blisters located? Do they itch?
• Have you observed any oozing, draining of pus or bleeding?
• Have you recently started new medications?
• Have you had a fever?