Pemphigoid is a rare autoimmune disorder that can develop at any age, including in kids, but that most often affects the elderly. Pemphigoid is caused by a malfunction of the immune system and results in skin rashes and blistering on the legs, arms, and abdomen.

Pemphigoid can also cause blistering on the mucous membranes. Mucous membranes produce mucous that helps protect the inside of your body. Pemphigoid can be found on the mucous membranes in your eyes, nose, mouth, and genitals. It can also occur during pregnancy in some women.

There’s no cure for pemphigoid, but there are various treatment options.

All types of pemphigoid are caused by your immune system attacking healthy tissue. They appear as rashes and fluid-filled blisters. The types of pemphigoid differ in terms of where on the body the blistering occurs and when it occurs.

Bullous pemphigoid

In cases of bullous pemphigoid — the most common of the three types — the skin blistering happens most commonly on the arms and legs where movement occurs. This includes the areas around the joints and on the lower abdomen.

Cicatricial pemphigoid

Cicatricial pemphigoid, also called mucous membrane pemphigoid, refers to blisters that form on the mucous membranes. This includes the:

  • mouth
  • eyes
  • nose
  • throat
  • genitals

The most common sites affected are the mouth and eyes. The rash and blistering may begin in one of these areas and spread to the others if left untreated. If it’s left untreated in the eyes, it may cause scarring, which in turn may lead to blindness.

Pemphigoid gestationis

When blistering occurs during or shortly after pregnancy, it’s called pemphigoid gestationis. It was formerly called herpes gestationis, although it’s not related to the herpes virus.

The blistering typically develops during the second or third trimester, but may occur at any time during pregnancy, or up to six weeks after delivery. Blisters tend to form on the arms, legs, and abdomen.

Pemphigoid is an autoimmune disease. This means that your immune system mistakenly begins to attack your healthy tissues. In the case of pemphigoid, your immune system creates antibodies to attack the tissue just below your outer layer of skin. This causes the layers of skin to separate and results in painful blistering. It’s not fully understood why the immune system reacts this way in people living with pemphigoid.

In many cases, there’s no specific trigger for pemphigoid, either. In some instances, however, it may be caused by:

  • certain medications
  • radiation therapy
  • ultraviolet light therapy

People with other autoimmune disorders are found to be at a higher risk for developing pemphigoid. It’s also more common in the elderly than in any other age group, and seems to occur slightly more in women than men.

The most common symptom of 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:

  • a red rash develops before the blisters
  • the blisters are large and filled with fluid that’s usually clear, but may contain some blood
  • the blisters are thick and don’t rupture easily
  • the skin around the blisters may appear normal, or slightly red or dark
  • ruptured blisters are usually sensitive and painful

Your dermatologist will be able to make a fairly firm diagnosis simply by examining your blisters. Further testing will be needed to prescribe the right treatment.

Your doctor may want to perform a skin biopsy, which involves removing small samples of skin from the affected areas. Lab technicians will test these samples for the immune system antibodies characteristic of pemphigoid. These antibodies can also be detected in your blood, so you may need to have a small sample of blood drawn.

Pemphigoid cannot be cured, but treatments are usually very successful at relieving symptoms. Corticosteroids, either in pill or topical form, will likely be the first treatment your doctor prescribes. These medications reduce inflammation and can help to heal the blisters and relieve itching. However, they can also cause significant side effects, especially from long-term use, so your doctor will taper you off of the corticosteroids after the blistering clears up.

Another treatment option is to take medication that suppresses your immune system, often in conjunction with the corticosteroids. Immunosuppressants help, but they may put you at risk for other infections. Certain antibiotics, such as tetracycline, may also be prescribed to reduce inflammation and infection.

With comprehensive treatment, the outlook for pemphigoid is good. Most people respond well to medication. The disease will often go away after a few years of treatment. But pemphigoid may return at any time, even with proper treatment.

If you develop any unexplained blistering, see your doctor. Prompt diagnosis and treatment will help to manage this condition faster.