Pemphigus foliaceus (PF) is an autoimmune skin disorder characterized by acantholysis of the epidermis (dissolution of the bridges between epidermal cells) resulting in superficial crusted erosions, typically in a seborrheic distribution. The predominant pathogenic antibodies, mostly immunoglobulin G4 (IgG4), are directed against desmoglein 1 (anti-Dsg1), although other antibody class subtypes against Dsg1 and autoantibodies against other antigenic targets have been described. PF has a geographic predilection, particularly South America and North Africa. There is no sex / gender predilection.

PF is generally considered a more benign form of pemphigus, and most patients do not become severely ill. However, in rare cases, lesions can progress to exfoliative erythroderma, potentially causing metabolic derangements. Oral lesions are rare, but skin lesions can persist for years.

PF may be seen in any age group but tends to be a disease of adults. An exception is the endemic subtype of PF (fogo selvagem) that can affect children and young adults in endemic areas (ie, Brazil, other parts of Latin America, and Tunisia). Pathogenesis of endemic PF is complex, involving genetic, environmental, and immunological factors. Environmental factors include the bite of some insects, such as the Similium black fly (Simulium nigrimanum). Pemphigus erythematosus (Senear-Usher syndrome) is another PF subtype and is considered a less severe form of the disease that typically affects the malar region and, rarely, also affects the seborrheic areas. Pemphigus erythematosus may coexist with other autoimmune disorders, such as myasthenia gravis or lupus erythematosus. It has also been reported in association with medications such as penicillamine. See Drug Reaction Data for more information.

Sun exposure or ionizing radiation are known triggers for PF.