Diagnosis of dermatitis herpetiformis by an avidin-biotin-peroxidase method.

BACKGROUND AND DESIGN: Immunofluorescence detection of stippled IgA in dermal papillae has been considered the gold standard in the diagnosis of dermatitis herpetiformis (DH). We have developed an immunohistochemical technique using the avidin-biotin-peroxidase complex that is equally effective as direct immunofluorescence in detecting IgA. We retrospectively studied 43 paraffin-embedded biopsy specimens obtained from patients with DH and a variety of other diseases for the presence of IgA along the basement membrane zone.

RESULTS: Eleven immunofluorescence-proved cases of DH were found positive for IgA with the avidin-biotin-peroxidase method. One biopsy specimen originally classified as DH was identified and reclassified as linear IgA bullous disease based on the immunoperoxidase findings. All the samples that were positive on direct immunofluorescence were positive with the avidin-biotin-peroxidase method. Control samples of bullous pemphigoid, discoid lupus erythematosus, pemphigus vulgaris, and dermatitis were all negative for IgA deposition.

CONCLUSION: The diagnosis of DH on formalin-fixed tissue is possible with the use of an avidin-biotin-peroxidase method, which is convenient and cost-effective.