Most skin rashes are nothing more than a nuisance, causing irritation or producing an unsightly blemish. However, certain skin rashes can be life-threatening. One such disorder is pemphigus vulgaris, an autoimmune disorder causing blistering of the mucous membrane and the skin. Patients with this condition produce IgG autoantibodies to a transmembrane glycoprotein (desmoglein 3), a protein responsible for adhesion in the skin cells. These antibodies produce an allosteric change in desmoglein 3, increasing the active plasmin in the area and decreasing cell adhesion, resulting in acantholysis and cell degradation. Pemphigus vulgaris can affect patients using certain medications, such as ACE inhibitors and chelating agents such as penicillamine, although this is a rare reaction. Pemphigus vulgaris can be found in all races at all ages, but is more common in middle age and older individuals and those of Middle Eastern or Jewish descent.
Pemphigus vulgaris is the most common form of pemphigus. Patients typically experience blisters in the mouth, which can spread onto the skin. Blisters can also appear on the mucous membranes of genitals as well as on the lining of the throat. These blisters can rupture easily, producing open sores that can ooze and become infected (a symptom characteristic to pemphigus). Rupturing of these blisters is exacerbated by scratching, which should be avoided if possible.
Two other forms of pemphigus include pemphigus foliaceus and paraneoplatic pemphigus. The former doesn’t affect the mucous membrane, and typically appears as crusted legions on the face and scalp, spreading to the chest and back. These legions are typically not painful, but can still rupture. Paraneoplastic pemphigus produces sores on the mouth and lip, within the esophagus in addition to skin legions. In some causes lesions can develop in the lung, causing progressive lung disease and dyspnea. This form of pemphigus is associated with certain forms of cancer.
Treatment of pemphigus depends on the severity of the individual case.