The etiology of pemphigus is largely unknown, although genetic predisposition is thought to be the cause. An endemic form of pemphigus foliaceus has been identified in certain rural areas of Brazil and may be transmitted by the bite of a black fly.
In rare cases, a medication can induce an attack. Such cases of pemphigus usually resolve after the offending drug is discontinued.
In paraneoplastic pemphigus, the skin problem is caused by cancer. The underlying cancer usually is lymphoid (lymphoma or leukemia) in origin. Paraneoplastic pemphigus typically resolves after the cancer has been treated successfully. Pemphigus also can be associated with benign lymph tumors.