Intracorneal nuclear dust aggregates in dermatitis herpetiformis. A clue to diagnosis.

Dermatitis herpetiformis has a characteristic histologic pattern consisting of subepidermal blisters often containing fibrin, infiltrates of neutrophils and nuclear dust at tips of dermal papillae, and papillary dermal edema. These are features of early and evolving lesions. We present two cases of clinically typical dermatitis herpetiformis with previously unreported histologic features that may provide a significant diagnostic clue. In each of these cases there were focal collections of nuclear dust in the cornified layer of the epidermis, a finding that may represent a resolving phase of dermatitis herpetiformis, beyond the usual papillary dermal neutrophilic microabscesses seen in early lesions. Biopsy material was available for immunofluorescent studies in one of the cases presented. In addition to the granular pattern of IgA positivity at the dermal-epidermal junction, which is diagnostic of dermatitis herpetiformis, this biopsy also showed similar IgA positivity in the intracorneal nuclear dust aggregates. In the second case, initial sections showed only intracorneal nuclear dust, but at deeper levels there were more typical diagnostic microabscesses at the tips of dermal papillae.