Pemphigus is a group of rare skin disorders that cause blisters of your skin or mucous membranes, such as in your mouth or on your genitals.

Pemphigus can occur at any age, but often strikes people in middle age or older. Although it affects all races and cultures, pemphigus tends to be more common in people of Middle Eastern or Jewish descent.

Usually a chronic condition, pemphigus is best controlled by early diagnosis and treatment, which may include medications or treatments similar to those used for severe burns. The less widespread your pemphigus is, the easier it may be to control.

Pemphigus is characterized by blisters on your skin and mucous membranes. The blisters rupture easily, leaving open sores, which may ooze and become infected. The signs and symptoms of the three main types of pemphigus differ depending on the type:

• Pemphigus vulgaris. The most common form, pemphigus vulgaris usually begins with blisters in your mouth, which then erupt on your skin. Blisters can also break out on the mucous membranes of your genitals. The blisters typically are painful, but don't itch.
• Pemphigus foliaceus. This type doesn't usually affect mucous membranes. The blisters, which usually begin on your face and scalp and later erupt on your chest and back, usually aren't painful. They tend to be crusty and itchy.
• Paraneoplastic pemphigus. This form, which may be associated with a malignancy, causes painful sores on your mouth and lips and in your esophagus, as well as skin lesions. This form of pemphigus can also cause lesions in your lungs, resulting in progressive lung disease and making it difficult for you to breathe (dyspnea).

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Pemphigus

Exactly what triggers pemphigus is unknown, but it's an autoimmune disorder.

Normally, your immune system attacks foreign invaders, such as harmful viruses and bacteria. But in pemphigus, your immune system mistakenly produces antibodies that attack healthy cells in your skin and mucous membranes, and more specifically proteins called desmogleins in the majority of cases. Desmogleins bind skin cells to each other. The antibodies binding to the skin cause separation of the cells of the top layer of your skin (epidermis). This separation reaction is known as acantholysis.

Sometimes, pemphigus develops as a side effect from certain medications, such as blood pressure drugs or chelating agents. This type of pemphigus usually disappears when the medicine is stopped.

Paraneoplastic pemphigus is caused by additional antibodies to those seen in other forms of the disorder. It develops in people who have cancer, usually lymphoma or leukemia. In cases in which the cancer hasn't yet been discovered, the appearance of pemphigus blisters may alert doctors to look for a malignancy.

Pemphigus isn't contagious, and there's no way to predict who'll get it. However, your risk increases if:

• You're middle-aged or older.
• You're of Mediterranean or Jewish descent.
• You have another autoimmune condition, particularly myasthenia gravis, a chronic disorder characterized by muscle weakness and fatigue, or thymoma, a tumor of the thymus. The thymus is an organ that produces white blood cells known as lymphocytes, an important part of your immune system.

See your doctor if you develop blisters inside your mouth or on your skin. If you've been treated for pemphigus, see your doctor if you develop any of the following:

• New blisters or sores
• A rapid spread in the number of sores
• Fever
• Chills
• Achy muscles or joints
• A general sense of feeling ill (malaise)

Because it's uncommon, pemphigus can be difficult to diagnose. Blisters are common to a number of conditions, so besides taking a medical history and examining your skin and mouth, your doctor may lightly rub unblistered skin with a cotton swab or finger. With pemphigus, the top layers of your skin are likely to separate easily from the lower layers (positive for Nikolsky sign). Other tests may include:

• Skin biopsy. In this test, a piece of tissue from a blister is removed and examined under a microscope. Examination of the biopsy tissue may also involve a process called direct immunofluorescence (DIF). DIF entails staining the tissue with fluorescent dye to make the antibodies "light up" under a special microscope so that they can be identified.
• Blood tests. The purpose of these tests is to detect and identify antibodies (anti-desmogleins) in your blood.

Possible complications of pemphigus are infection of your skin and spread of infection through your bloodstream (sepsis). Systemic infection can be fatal.

Complications of paraneoplastic pemphigus include respiratory problems. The mortality rate for this type of pemphigus is estimated to be 90 percent, independent of the underlying cancer.

Other complications are the possible side effects of the medications used to treat pemphigus, particularly corticosteroids.

Treatment, which aims at reducing signs and symptoms and preventing complications, is most effective when it begins as early as possible. The less widespread pemphigus is, the easier it may be to control. Specific treatment methods depend on the severity of the disease.

Mild pemphigus
If your pemphigus isn't too widespread, you may be able to remain at home for treatment. The mainstay of treatment is usually corticosteroids, such as prednisone. However, using corticosteroids over an extended time or in high doses may cause serious side effects, including:

• Weight gain
• Mood swings
• Elevated blood sugar (diabetes)
• Osteoporosis
• Redistribution of body fat, leading to a round face (moon face)
• Increased chance of infection because of suppression of the immune system

Corticosteroids may be combined with other medications, including:

• Immunosuppressants. These medications, such as azathioprine (Imuran) or methotrexate (Rheumatrex), help keep your immune system from attacking healthy tissue. These drugs have serious side effects, including increased risk of infection.
• Antibiotics and antifungal medications. These may be prescribed to control or prevent infections.

Additionally, other medications, such as dapsone, intravenous immunoglobulin and rituximab (Rituxan), also may be prescribed. These medications have had some success in treating pemphigus in small clinical trials.

Severe pemphigus
Widespread pemphigus may require you to stay in the hospital, where you may receive treatment similar to treatment for severe burns. The open sores make you highly vulnerable to infection, which, if it spreads to your bloodstream, may be fatal. Along with the medications listed above, you may also be given:

• Fluids. Because you may have lost bodily fluids due to oozing of the sores, you may receive fluids through a vein (intravenously), as well as electrolytes — minerals such as sodium, potassium and calcium that maintain the balance of fluids in your body — and proteins.
• Intravenous feeding. This may be necessary if mouth sores make it too painful for you to eat.
• Anesthetic mouth lozenges. These can help control pain of mild to moderate mouth sores.
• Therapeutic plasmapheresis. In this process, the fluid part of your blood, called plasma, is removed from blood cells by a device known as a cell separator. The purpose is to get rid of the antibodies that are attacking your skin. The plasma is replaced with donated plasma or intravenous fluids.

Pemphigus and some of the drugs used to treat it render your skin fragile and prone to infection. Here are some things you can do:

• Minimize trauma to your skin. Avoid situations in which your skin could be touched or bumped, such as contact sports.
• Ask your doctor for wound care instructions. Taking good care of your wounds can help prevent infection and scarring.
• Use talcum powder. Generously sprinkling talcum powder on your sheets may help keep oozing skin from sticking.
• Use lotions or dressings. To ease discomfort, treat sores and blisters with soothing or drying lotions or wet dressings.

Some cases of pemphigus can be debilitating, especially before treatment starts to work. To help you cope with the disease and the effects of the drugs used for treatment, you may find it helpful to talk to others with the condition. You can find in-person or virtual support groups. Ask your dermatologist or contact the International Pemphigus & Phemigoid Foundation.