Anti-endomysial antibodies. A serologic marker of dermatitis herpetiformis.

Direct immunofluorescence (IF) studies of skin biopsies are of value in the diagnosis of most, but not all, cases of dermatitis herpetiformis (DH). Similarly, histologic studies are of help but may be questionable or completely nonspecific. Serologic studies for the presence of IgA-class anti-endomysial antibodies are very specific and are found in 70% of patients with DH and in all untreated patients with celiac disease. The titers of these antibodies are directly associated with the degree of gut disease in these patients. Thus, the presence of these antibodies even in the absence of classic direct IF and histologic findings are diagnostically important. We encountered three cases in which both direct IF and histologic studies were equivocal toward confirming the clinical diagnosis of DH. Serologic studies for the presence of IgA-class anti-endomysial antibodies provided evidence for the diagnosis of DH, and, in each case, results were confirmed by further direct IF studies. Since these antibodies are disease specific for DH and celiac disease and are found in most active cases of DH, they may be considered an adjunct to the direct IF and histologic studies of the skin.