DefinitionPemphigus vulgaris is an autoimmune disorder that involves blistering of the skin and mucous membrane.Causes, incidence, and risk factorsPemphigus is an autoimmune disorder. The immune system produces antibodies against specific proteins in the skin and mucous membrane. These antibodies create a reaction that cause skin cells to separate. The exact cause is unknown.Sometimes pemphigus is caused by certain medications, although this is rare. Medications that may cause this condition include:Blood pressure medications called ACE inhibitorsChelating agents such as penicillamine, which remove certain materials from the bloodPemphigus is uncommon. It occurs almost exclusively in middle-aged or older people.SymptomsAbout 50% of cases begin with blisters in the mouth, followed by skin b