Dermatitis herpetiformis most often occurs in adults aged about 30 to 40 but can occur in children and older adults (1). It is rare in Black and Asian people.
Almost all patients with dermatitis herpetiformis have celiac disease histologically, but in most cases the celiac disease is asymptomatic. Dermatitis herpetiformis develops in 15 to 25% of patients with celiac disease. Patients may have a higher incidence of other autoimmune disorders (including thyroid disorders, pernicious anemia, and diabetes) and small-bowel lymphoma. IgA deposits collect in the dermal papillary tips and attract neutrophils; they can be eliminated by a gluten-free diet.
The term herpetiformis refers to the clustered appearance of the lesions (similar to that seen in herpesvirus infection) but does not indicate a causal relationship to herpesvirus.
General reference
1. Nguyen CN, Kim SJ: Dermatitis herpetiformis: An update on diagnosis, disease monitoring, and management. Medicina (Kaunas) 57(8):843, 2021. doi: 10.3390/medicina57080843
Symptoms and Signs of Dermatitis Herpetiformis
Onset of dermatitis herpetiformis can be acute or gradual. Vesicles, papules, and urticarial lesions are usually distributed symmetrically on extensor aspects of the elbows and knees and on the sacrum, buttocks, and occiput. Lesions itch and burn. Because itching is intense and skin is fragile, vesicles tend to rupture quickly, often making intact vesicles difficult to detect. Oral lesions may develop but are usually asymptomatic. Iodides and iodine-containing preparations may exacerbate the cutaneous symptoms.
Diagnosis of Dermatitis Herpetiformis
Skin biopsy and direct immunofluorescence
Serologic markers
Diagnosis of dermatitis herpetiformis is based on skin biopsy and direct immunofluorescence testing of a lesion and adjacent (perilesional) normal-appearing skin. Direct immunofluorescence showing granular IgA deposition in the dermal papillary tips has a sensitivity of approximately 90 to 95% and specificity of approximately 95 to 100% (1).
All patients with dermatitis herpetiformis should be evaluated for celiac disease. Serologic markers such as IgA anti-tissue transglutaminase antibody, IgA anti-epidermal transglutaminase antibody, and IgA anti-endomysial antibody can help confirm the diagnosis and aid in monitoring disease progression.
Diagnosis reference
1. Antiga E, Caproni M: The diagnosis and treatment of dermatitis herpetiformis. Clin Cosmet Investig Dermatol 8:257-265, 2015. doi: 10.2147/CCID.S69127
Treatment of Dermatitis Herpetiformis
Gluten-free diet
glucose-6-phosphate dehydrogenase (G6PD) deficiency
Patients are also placed on a strict gluten-free diet. After initial therapy and disease stabilization, most patients can stop pharmacologic therapy and be maintained on the gluten-free diet, but this may take months or years. A gluten-free diet also maximizes improvement in the enteropathy and, if strictly followed for 5 to 10 years, decreases risk of small-bowel lymphoma.
Treatment reference
1. Nguyen CN, Kim SJ: Dermatitis herpetiformis: An update on diagnosis, disease monitoring, and management. Medicina (Kaunas) 20;57(8):843, 2021. doi: 10.3390/medicina5708084
Key Points
Almost all patients who have dermatitis herpetiformis, even if they have no gastrointestinal symptoms, have histologic evidence of celiac disease and are at risk of small-bowel lymphoma.
Because itching is intense and skin is fragile, vesicles may all be broken and thus not evident on examination.
Confirm the diagnosis with skin biopsy, direct immunofluorescence testing of a lesion and adjacent normal-appearing skin, and serologic tests.
Have patients try to maintain long-term control with only a strict gluten-free diet so that pharmacologic therapy can be stopped.
