Pemphigus herpetiformis (PH) is a rare autoimmune disorder characterized by a clinical appearance resembling dermatitis herpetiformis, along with histological and immunopathological features of pemphigus. While some classify PH as an atypical variant of pemphigus foliaceus (PF) or pemphigus vulgaris (PV), PH is generally considered a distinct clinical entity.

PH is rare, with approximately 100 cases reported in the literature, typically manifesting in middle-aged adults as an intensely pruritic cutaneous eruption with herpetiform clusters of vesicles. PH rarely affects children, with fewer than 10 reported cases in the literature. No ethnic or sex predilections have been observed.

The inciting factors of the disease include generation of immunoglobulin G (IgG) autoantibodies that recognize desmoglein 1 (less commonly, desmoglein 3 or desmocollin 1 or 3) on keratinocytes, stimulating upregulation of interleukin-8, which serves as a chemoattractant for eosinophils and neutrophils. In turn, these inflammatory cells secrete proteases that mediate eosinophilic or neutrophilic spongiosis and blister formation.

Unlike the classical pemphigus disorders, PH usually exhibits a benign clinical course. However, cases of PH progressing to PF or PV have been reported.

PH has been rarely reported to be associated with internal malignancies, most commonly lung cancer, but PH has been reported with various other cancers (eg, esophageal cancer and cutaneous angiosarcomas). Association with other inflammatory / autoimmune conditions and infections have been reported, including psoriasis, systemic lupus erythematosus, autoimmune hemolytic anemia, and HIV infection.