What is Dermatitis Herpetiformis ?
Dermatitis herpetiformis (DH) is a chronic, intensely itchy, blistering skin manifestation of gluten sensitive enteropathy, commonly known as celiac disease. DH affects 15 to 25 percent of people with celiac disease. Most people with DH have no other symptoms of celiac disease. DH is found mainly in adults and is more common in men and people of northern European descent.

Symptoms
DH is characterized by small, clustered papules and vesicles that erupt symmetrically on the elbows, knees, buttocks, back, or scalp. Men may also have oral or genital lesions. A burning sensation may precede lesion formation. Lesions are usually scratched off by the time a patient comes in for a physical exam.

Causes
DH is caused by the deposit of immunoglobulin A  in the skin, which triggers further immunologic reactions resulting in lesion formation. DH is an external manifestation of an abnormal immune response to gluten, in which  antibodies form against the skin antigen epidermal transglutaminase.


Diagnosis
A skin biopsy is the first step in diagnosing DH. Direct immunofluorescence of clinically normal skin adjacent to a lesion shows granular  deposits in the upper dermis. Histology of lesional skin may show microabscesses containing neutrophils and eosinophils but may reveal only excoriation due to the intense itching patients experience.

Skin biopsies performed on the affected skin are nearly always positive for  deposition. Blood tests for antiendomysial or anti-tissue transglutaminase antibodies may also suggest celiac disease.

A positive biopsy and serology confirm celiac disease. In the absence of these results, patients should be referred to a gastroenterologist for a definitive diagnosis via intestinal biopsy.


Treatment
Dapsone, a sulfone, provides immediate relief of symptoms. For patients who cannot tolerate dapsone, sulfapyridine or sulfamethoxypyridazine may be used, although these drugs are less effective than dapsone. A strict gluten-free diet is the only treatment for the underlying disease. Even with a gluten-free diet, drug therapy may need to be continued for 1 to 2 years.

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  Dermatitis Herpetiformis