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Man with blisters on his elbows.
31 year old man with 4 month history of pruritic vesicles and crusts on his forearms, scalp, posterior neck and backside.
He is otherwise healthy, no medications.
What is your diagnosis?
Diagnosis:
Dermatitis Herpetiformis
Dermatitis herpetiformis (also known as Duhring disease) is an intensely pruritic immuno-vesiculoboullous disorder. Lesions commonly occur on forearms, scalp, posterior neck and backside. The blistering reaction is mediated by an IgA autoantibodies. The condition is so intensely pruritic, that most patients present with ulcers and crusts, rather that vesiculobullae from excoriation.
Dermatitis herpetiformis often affects young adults and 65% of patients are male. There is an association with human leukocyte antigens (HLAs) DQ2 DQ8.
DH is associated with celiac disease and 80% of patients with dermatitis herpetiformis also have a gluten sensitivity/enteropathy, the most common form of celiac disease. Biopsy is diagnostic, showing dermal microabsesses rich in neutrophils. The condition can be intensely and extraordinarily pruritic.
This is a relatively rare condition, but like such conditions, if the examiner does not consider it in the differential, it may be missed.
Treatment
Make sure to address any potential cutaneous infections upon presentation.
In my experience, Dapsone is the treatment of choice. Starting at 100mg/day. Some patients may require up to 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, make sure the patient is not G6PD deficient or you may get a phone call from the ER (as I did on the first and only patient I did not check) that your patient is blue and not feeling or doing well.
Most patients who are successfully managed with Dapsone are extremely grateful.
The name 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 additional information/references please see:
http://en.wikipedia.org/wiki/Dermatitis_herpetiformis
http://emedicine.medscape.com/article/1062640-overview
http://dermnetnz.org/immune/dermatitis-herpetiformis.html
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