This 55-year-old man presented with pruritus followed by grouped vesicles on his upper extremities (hands, elbows). This is a fairly typical example of dermatitis herpetiformis, but the patient is older than usual. Pruritus, symmetric clustered vesicles, and gluten-sensitive enteropathy are all commonly seen. This man had no history of celiac sprue, but was being placed on a trial of a gluten-free diet. The histopathology is fairly typical in this case. A well-established blister cavity is not present in the plane of section, but neutrophils predominate as the infiltrate, and classically aggregate in the dermal papillae. The differential diagnosis includes linear IgA (usually more confluent than clulstered) and other subepidermal vesicobullous disorders. The diagnosis in confirmed in this case by visualizing the granular IgA deposition in the dermal papillae tips on direct immunofluorescence.
Histologic sections of skin show several collections of neutrophils, in clusters, concentrated in the dermal papillae. There is focal linear deposition of neutrophils along the dermal-epidermal junction, with focal clefting.