Bullous pemphigoid is uncommon and rare disease that causes blistering of the skin. Bullous pemphigoid is caused by a malfunction of the immune system and results in skin rashes and blistering on the legs, arms, and abdomen. Bullous pemphigoid can also cause blistering on the mucous membranes of the eyes, nose, mouth, and vagina, and can occur during pregnancy in some women. Bullous pemphigoid can be life-threatening, especially for older people who are already in poor health. The disease will go away after a few years of treatment. Even with proper treatment, however, pemphigoid may return at any time.
The cause of bullous pemphigoid is not well understood. The blisters occur because of a malfunction in the 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 skin’s basement membrane, a thin layer of fibers connecting the outer layer of skin and the next layer of skin. These antibodies trigger inflammatory activity that produces the blisters and itching of bullous pemphigoid.
The most common symptom of bullous pemphigoid is blistering that occurs on the arms, legs, abdomen, and mucous membranes. Hives and itching are also common. The blisters have certain characteristics, regardless of where on the body they form:
- they are often preceded by a red rash
- they are large and filled with fluid that is usually clear, but may contain some blood they are thick and do not rupture easily
- the skin around the blisters may appear normal or slightly red or dark
- ruptured blisters are usually sensitive and painful
Tests and Diagnosis
Your GP may suspect bullous pemphigoid just by looking at your skin.
The diagnosis is then confirmed by taking a small sample of your affected skin (biopsy) and sending it to a laboratory to be inspected, to see if the top layers of skin have separated.
Special staining (immunofluorescence) may be used to show up the antibodies, and a blood sample may be taken and checked for the presence of pemphigoid antibodies.
The goals of bullous pemphigoid treatment are to help the skin heal as quickly as possible and relieve itching. Your doctor will likely prescribe a combination of drugs that inhibit immune system activities that cause inflammation. These drugs may include:
- 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 cataracts. Corticosteroid ointment can be rubbed on your affected skin and cause fewer side effects.
- Immunosuppressants. These drugs inhibit the production of your body’s disease-fighting white blood cells. Examples include azathioprine (Azasan, Imuran) and mycophenolate mofetil (CellCept). Immunosuppressants are often used to help reduce the dosage of prednisone you may need.
- Anti-inflammatories. A variety of drugs with anti-inflammatory properties may be used alone or in combination with corticosteroids. Examples include methotrexate (Trexall), a rheumatoid arthritis drug; tetracycline, an antibiotic with anti-inflammatory properties; and dapsone (Aczone), a leprosy treatment.
Looking after your skin
Blisters should be left intact, if possible, to reduce your risk of infection. However, if they’re particularly large and in a difficult place like on the sole of your foot they may be carefully pierced with a sterile needle to release the fluid. The skin of the blister should be left. If blisters do break, they heal quickly.
Call your doctor immediately if you have:
- Unexplained blisters on your skin
- An itchy rash that continues despite home treatment
With comprehensive treatment, the outlook for pemphigoid is good. Most people respond well to medication. Bullous pemphigoid may return at any time even with proper treatment.