Dermatitis Herpetiformis: A Review of Direct Immunofluorescence Findings.

Direct immunofluorescence (DIF) findings in dermatitis herpetiformis (DH) are incompletely defined. The presence and localization of immune reactants in this disorder are reviewed. A retrospective study on 72 biopsies from 71 patients with DH was performed. Deposits of IgG, IgA, IgM, C'3, C1q, and fibrinogen in skin using a DIF test were analyzed. Granular IgA was observed at the dermal-epidermal junction in 65 biopsies and in the fibers of the papillary dermis in 72 samples. IgG, IgM, C'3, C1q, and fibrinogen were detected in the same locations in lower percentages. IgA was present in the vessels of the papillary dermis in 33 biopsies and in the reticular dermis in 10, followed by fibrinogen, C'3, IgM, and IgG. IgA and IgM were detected in the elastic fibers in 17 and 5 samples, respectively. IgA was observed in 19 cases in the arrector pili muscles, and in a few cases, C'3, IgM, and IgG. IgA and other immune reagents were present in the fibers around hair follicles and in the basement membrane of sweat glands and ducts. Immunofluorescence findings in routine DIF studies from skin biopsies of patients with DH cover a much wider spectrum than previously known.