Dietary management of dermatitis herpetiformis.

Dermatitis herpetiformis (DH) is an extremely itchy, papulovesicular skin disease characterized in part by the presence of IgA at the dermal-epidermal junction. Eighty-five percent to 90% of DH patients have granular deposits of IgA at the dermal-epidermal junction, and essentially all of these patients have an associated, for the most part asymptomatic, gluten-sensitive enteropathy (GSE). The association of GSE and DH suggested that the cutaneous manifestations of DH could be controlled by the use of a gluten-free diet. Institution of a gluten-free diet in patients with DH and granular IgA deposits has been shown to be effective in controlling the cutaneous eruption of DH. Seventy percent to 100% of patients who begin a strict gluten-free diet have been shown to be able to decrease the dosage of medication needed to control their DH after a mean of eight to 18 months on the diet. Furthermore, 40% to 70% of patients with DH can control their skin disease completely, without any medication, after longer periods of time on the gluten-free diet (two years and longer). Although the gluten-free diet has been shown to be of great benefit in the control of the skin manifestations of DH, at the present time there is no evidence to suggest that the gluten-free diet is in any way protective against the risk of intestinal lymphoma that has been documented in GSE. Evaluation of the cutaneous IgA deposits in DH skin after long periods of time on a gluten-free diet suggests that there may be a slight decrease in the intensity of the IgA deposits, but the true pathogenetic relationship between the cutaneous IgA deposits, the cutaneous manifestations of DH, and the associated GSE remains unknown.