Dermatitis herpetiformis: should direct immunofluorescence be the only diagnostic criterion?

We describe a 7-year-old boy with dermatitis herpetiformis (DH) diagnosed on clinical and histologic evidence, negative direct immunofluorescence (DIF) findings for junctional IgA deposits in uninvolved skin, positive IgA endomysial and gliadin antibodies, and jejunal biopsy revealing a gluten-sensitive enteropathy. Treatment with dapsone led to the disappearance of cutaneous lesions and pruritus within 48 hours. Demonstration of IgA immune deposits in the dermal papillae has been the only acceptable criterion for the diagnosis of dermatitis herpetiformis. However, considering several reports in the literature of DH with a negative DIF and our own case, we believe that in the absence of the characteristic DIF pattern, one needs the combination of clinical, histologic, and immunologic data to support the diagnosis of DH. We also discuss recent developments in the diagnosis of DH.