Pemphigus vulgaris occurs when the immune system mistakenly makes antibodies against proteins in healthy skin and mucous membranes. ... This leads to blisters and erosions on the skin. The precise cause of the attack by the immune system isn't known. Very rarely, certain medications can cause pemphigus vulgaris. Pemphigus vulgaris is an autoimmune, intraepithelial, blistering disease affecting the skin and mucous membranes. It is mediated by circulating autoantibodies directed against keratinocyte cell surfaces. A potentially life-threatening disease, it has a mortality rate of approximately 5-15%. This might be a chemical or a medicine. In some cases, pemphigus vulgaris will go away once the trigger is removed. The condition causes the immune system to fight against the body's own cells in the same way that it fights off invading germs