Dermatitis Herpetiformis

Dermatitis herpetiformis (DH) is an autoimmune skin disease caused by eating wheat protein called gluten.  It has nothing to do with the infection caused by the Herpes virus.  In DH, the patient becomes allergic to gluten and produces antibodies that cause extremely itchy red bumps and blisters on the skin and damage to the lining of the small intestine.  This injury to the small intestine resembles another severe condition called Celiac Disease which is characterized by poor absorption of some nutrients and diarrhea.

The rash of DH can occur anywhere on the skin, but it seems to favor the scalp, shoulder

Dermatitis herpetiformis: Note that only crusted papules and white scars remain after scratching.

blades, elbows, knees, and buttocks.  Intact blisters may not be seen because the patient has rubbed or scratched them off

Dermatitis herpetiformis: Note red hive-like rash with many crusted papules which were formerly blisters.

during bouts of intense burning itch.  Instead, red bumps, scabs, and white scars may be the only remaining signs of the disease.

The diagnosis of DH can be confirmed by taking  skin biopsy specimens of a lesion, preferably one that has not been scratched (may be difficult to find), and of surrounding skin for a test called direct immunofluorescence.  In true cases of DH, these biopsies show a fluid-filled blister containing neutrophil white blood cells and granular deposits IgA antibodies below the blister, respectively.  On the other hand, Celiac Disease can be diagnosed by a panel of blood tests for the causative antibodies or a small bowel biopsy performed by a gastroenterologist.

Although DH is a rare and serious disease, it can be cured by following a strict gluten-free diet.  Because it may take up to 2 years for the cure to occur, we also treat patients with a drug called Dapsone.  Dapsone induces the itching to stop within a matter of days followed by healing of the rash.  Before we prescribe Dapsone, we order a blood test called G6PD screen to make sure the patient doesn’t have a genetic deficiency of an enzyme that would make them more sensitive to the drug.

Every drug has side effects, and Dapsone is no exception.  Dapsone can cause anemia because it oxidizes the hemoglobin in red blood cells.  In order to prevent anemia, we recommend that patients also take antioxidants such as vitamin C, vitamin E, and Green Tea Extract.  After taking a gluten-free diet for 6 months to 2 years, the dose of Dapsone may be reduced or eventually stopped without a recurrence of the rash, blisters or itching.

Drawing of models of Dermatitis herpetiformis (right panel) in Saint Louis Hospital, Paris, 1904.

Dermatitis herpetiformis was first described by Duhring over 100 years ago and was initially named after him.  I found the following treatment recommendations in a Dermatology textbook published in 1904.  I include them here only for your historical interest and to emphasize the progress Dermatology has made as a specialty of Internal Medicine:

“Treatment can only be symptomatic….  Lotions containing alcohol, sulphur baths and tarry preparations often act favourably; as may the internal administration of arsenic and strychnine.”

Please do not try this “remedy” at home!

More About Autoimmune diseases:Gluten Sensitivity and Gluten-Free Diets in Dermatology
Skin Diseases and Granulocyte White Blood Cells: Hidradenitis Suppurativa, Sweet’s Syndrome, and Pyoderma Gangrenosum

 

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