Medical Care
Treatment of dermatitis herpetiformis (DH) include avoidance of gluten by consuming a gluten-free diet and pharmacotherapy. [45]
A gluten-free diet is a lifelong commitment, and adherence to a strict diet is difficult to achieve. Improvement of skin disease with a gluten free diet takes several months. Gluten is present in various foods that are consumed on an everyday basis, most importantly wheat, barley, and rye. Concern has surrounded oats containing gluten, but studies have shown that consumption of a moderate amount of oats does not worsen dermatitis herpetiformis or celiac disease. [46, 47] Contamination of gluten-free products with gluten remains a potential problem. [48] Nutritional supplementation with multivitamins and iron may be prudent in patients on a strict gluten-free diet. [49]
Dapsone (diaminodiphenyl sulfone) and sulfapyridine (no longer available in most countries) are the primary medications used to treat dermatitis herpetiformis. The exact mechanism of action is unknown but is thought to be related to inhibition of neutrophil migration and function. Patients report a symptomatic improvement within hours after initiation of dapsone therapy. Patients should be monitored for the adverse effects of dapsone, primarily hemolytic anemia, methemoglobinemia, agranulocytosis, and neuropathy. For patients unable to tolerate dapsone, particularly those who develop hemolysis, sulfapyridine may be substituted. New lesion formation is suppressed for up to 2 days after a dose of dapsone; however, dapsone does not improve GI mucosal pathology.
A retrospective study has shown remission, defined as 2 years with no symptoms, in 12% of patients. [50] When dermatitis herpetiformis is well-controlled, attempts can be made to taper off dapsone and perhaps attempt a diet with gluten. Although sulfapyridine is no longer available in the United States, sulfasalazine may be prescribed. Sulfasalazine is partly metabolized to sulfapyridine. Sulfasalazine has been used by itself or in combination with dapsone. [51]
Other, less effective treatments for dermatitis herpetiformis include colchicine, cyclosporine, azathioprine, and prednisone. [41] Ultraviolet light may provide some symptomatic relief. The combination of tetracycline and niacinamide has been reported to successfully treat it. Cyclosporine should be used with caution in patients with dermatitis herpetiformis because of a potential increase in the risk of developing intestinal lymphomas. Because it is an antibody-induced autoimmune disease, therapies aimed at removal of the antibodies may be helpful; rituximab and intravenous immunoglobulin may be helpful in particularly severe cases not improved by other medications that are less expensive and carry fewer adverse effects. [52]
One case report described resolution of dermatitis herpetiformis after initiation of the Atkins diet. [53]
NSAIDs may exacerbate dermatitis herpetiformis. [54]
Iodides may elicit or exacerbate dermatitis herpetiformis.
Consultations
Consider consultation with a gastroenterologist for evaluation and for recommendations regarding gluten-sensitive enteropathy (GSE).
Consult with a dietitian regarding patients who are modifying dietary intake to avoid gluten or who are instituting an elemental diet.
Diet
Dietary intake of gluten causes the disease, and elimination of gluten from the diet improves it.
A position statement by the American Gastroenterological Association (AGA) Institute advises that treatment for patients with dermatitis herpetiformis, like that of all patients with celiac disease, requires a strict, lifelong adherence to a gluten-free diet. The AGA stresses the importance of patient education, motivation, and support in maintaining adherence, and recommends consultation with an experienced dietician, referral to a support group, and clinical follow up for compliance, as well as treatment of nutritional deficiency states. [55]
Most patients (as many as 80%) who can maintain a gluten-free diet respond with control of their skin disease. Some patients are able to discontinue dapsone therapy. Compliance with a gluten-free diet is difficult and requires a motivated patient, and the best treatment response occurs with absolute gluten restriction in the diet.
Strict dietary vigilance may be required for 5-12 months before the dapsone dose can be reduced.
Maintaining a gluten-free diet is the only sustainable method of eliminating the disease, not only from the skin, but also from the GI mucosa.
Patients on a gluten-reduced diet may experience a decrease in symptoms; therefore, such a diet can reduce the dosage of dapsone required for disease control.
Neither IgA deposition nor circulating antibodies correlate with gluten intake in short-duration studies; however, some studies have suggested a correlation with complement deposition. Avoidance of dietary gluten for 10 years or more has resulted in loss of cutaneous IgA deposits, which then return upon reinstitution of gluten in the diet.
Elemental diets may improve the disease within weeks. [56, 57] These diets consist of free amino acids, small amounts of triglycerides, and short-chain polysaccharides; they are marketed by pharmaceutical companies. One report has suggested that this improvement may be independent of gluten ingestion; however, this finding has not been confirmed. [57]
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Light micrograph shows neutrophils in the dermal papillae, with fibrin deposition, neutrophil fragments, and edema (hematoxylin and eosin stain).
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Papillary microabscesses form and progress to subepidermal vacuolization and vesicle formation in the lamina lucida, the weakest portion of the dermoepidermal junction (hematoxylin and eosin stain).
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Classic vesicles of dermatitis herpetiformis.
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Immunofluorescence showing immunoglobulin A at the dermoepidermal junction (direct immunofluorescence stain).
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Polymorphic lesions on extensor surface of arm.
