Common Immunobullous Disorders of the Skin
Immunobullous (blistering) diseases of the skin are autoimmune disorders. Any autoimmune condition involves the immune system “attacking” its own organs or tissues by producing autoantibodies (antibodies against the self). In the skin, there are proteins that attach epidermal cells to each other and proteins that attach the epidermis to the dermis. These proteins are the glue that keeps the skin intact. When these proteins are damaged by autoantibodies, the cells separate from each other and a blister appears. The two main forms of immunobullous disease of the skin are Pemphigus and Pemphigoid.
Pemphigus presents as blistering and raw sores inside the mouth or on the skin. In some people, both locations are affected. Pemphigus is derived from the Greek word pemphix meaning bubble or blister. In Pemphigus, autoantibodies attack proteins that connect each epidermal cell to each other. There are three main types: pemphigus vulgaris, pemphigus foliaceus, and paraneoplastic pemphigus.
- Pemphigus vulgaris most commonly occurs in people between the ages of 40-60, often of Jewish or Mediterranean descent. Pemphigus vulgaris most often affects the inside of the mouth.
- Pemphigus foliaceus is characterized by crusty sores that often begin on the scalp, and may move to the chest, back, and face. It is not as painful as pemphigus vulgaris, and is often mis-diagnosed as dermatitis or eczema.
- In paraneoplastic pemphigus, painful sores appear on the mouth, lips, and the esophagus. This type of pemphigus is associated with underlying cancer. Paraneoplastic pemphigus usually results in fatal destruction of lung tissue (bronchiolitis obliterans).
- The diagnosis of any pemphigus variant relies on visual examination of skin lesions, skin biopsy which must include direct immunoflourescence examination.
- If not treated, pemphigus can be fatal, due to overwhelming systemic infection and fluid losses through the skin. Pemphigus can cause scarring in severe cases, or when secondary infections occur.
- The most common treatment is the administration of oral corticosteroids, usually prednisone, in conjunction with “steroid sparing” agents or immunosuppressants. These drugs quiet the immune attack so that blistering stops and sores can heal.
There are two major forms of Pemphigoid, Bullous Pemphigoid and Mucous Membrane (Cicatricial) Pemphigoid. The type of Pemphigoid one has depends on the autoantibodies that are present.
Bullous Pemphigoid (BP) is a blistering disease of the skin caused by autoantibodies directed against skin proteins that connect the epidermis and the dermis. BP causes blisters, itching and sometimes pain. The majority of patients with BP experience remission within five years of initial diagnosis, but sometimes the disorder relapses. BP can often be treated with a combination of topical steroids and non-steroidal medications, but there are cases in which treatment with oral corticosteroids or immunosuppressants is required because of more severe or widespread blistering. BP blisters usually heal without scarring. Good wound care is important to promote healing and prevent infection and scarring.
Mucous Membrane Pemphigoid (MMP or Cicatricial pemphigoid) is a blistering disease than can arise on any mucous membrane surface including the nose, mouth, eyes, esophagus, larynx, urethra and anal mucosa. Scarring commonly occurs in affected areas and spontaneous improvements and remissions are rare. The affected organs dictate what treatment should be used. Systemic steroids are generally not adequate to control progression of MMP. Dapsone is drug that can be helpful in less severe cases of MMP. Azathioprine, mycophenolate mofetil and cyclophosphamide are immunosuppressant medications that are used in severe cases of MMP. It is important to treat this condition promptly to avoid scarring. Sometimes it is difficult to make the initial diagnosis of MMP; more than one biopsy may be needed to confirm the diagnosis and implement appropriate therapy.