This 31-year-old man has a four-month history of pruritic vesicles and crusts on his forearms, scalp, posterior neck and backside. He is otherwise healthy and takes no medications.
Diagnosis: Dermatitis Herpetiformis
Dermatitis herpetiformis (also known as Duhring’s disease) is an intensely pruritic immuno-vesiculobullous disorder. Lesions commonly occur on forearms, scalp, posterior neck and backside. The blistering reaction is mediated by IgA autoantibodies. Because the condition is so intensely pruritic, most patients present with ulcers and crusts, rather than vesiculobullae from excoriation.
Dermatitis herpetiformis often affects young adults, and 65 percent of afflicted patients are male. An association exists with human leukocyte antigens DQ2 and DQ8. The condition is associated with celiac disease; 80 percent of patients with dermatitis herpetiformis also have a gluten sensitivity/enteropathy, the most common form being celiac disease.
Biopsy is diagnostic, showing dermal microabscesses rich in neutrophils. This is a relatively rare condition and, as such, if the examiner does not consider it in the differential, it may be missed.
Be sure to address any potential cutaneous infections upon presentation.
In my experience, Dapsone is the treatment of choice. The typical beginning dose is 100 mg/day; however, some patients may require as much as 300 mg/day. I do have one patient who successfully manages his condition with only 25 mg/day. Every patient is unique, and you have to titrate the amount to find the best dose for your patient. Most patients do well in the 100–200 mg/day range. If using Dapsone, be sure the patient is not G6PD deficient, or you may get a phone call from the ER saying your patient is blue and not feeling or doing well (as I did with the first and only patient whom I did not check).
Most patients who are successfully managed with Dapsone are extremely grateful.
The name “dermatitis herpetiformis” is of historic significance only. Long ago, the blistering nature of the condition caused people to think it was a viral/herpetic infection, or better, herpetic-like. We know that is not true, but the name has survived to confuse and torment medical students and residents on qualifying examinations.
For more information, contact Charles E. Crutchfield III, MD, at Crutchfield Dermatology or visit www.CrutchfieldDermatology.com