The first mention of Dermatitis Herpetiformis (DH) in the literature was in 1884 in Dhring. The connection to wheat was made in Dreke, Holland in 1941. It is an uncommon, but not rare, disease that affects males twice as often as females. It is found in 10% of first degree relatives. There is a genetic association; 90% of DH patients have HLA-B8 vs. only 15% of the general population. HLA-DRw4 and HLA-DQw2 are also associated with some DH patients.
DH normally is found on elbows, knees, shoulders, buttocks, sacrum, posterior scalp, and face. While it is unusual, it can also show upon the hands or inside the mouth. It presents as clear blisters that itch very badly. [One patient described the itch ...like rolling in poison ivy naked with a severe sunburn, then wrapping yourself in a wool blanket filled with ants and fleas.-ed]
The original diagnosis of DH was done by giving Dapsone, a leprosy drug, and noting any improvement. Today, the gold standard for diagnosing DH is a skin biopsy with immunofluorescence. (A plain skin biopsy is not sufficient.) Most DH patients also have villi damage in the small intestine and lymphocyte infiltration of the intestinal wall, and IgA/IgG antigliadin antibodies in the bloodstream. However, there is really no need to perform a small bowel biopsy or test for blood serum antibodies; the skin biopsy with immunofluorescence provides a definitive diagnosis.
Dr. Papp indicated that about half of his patients are diagnosed after having their symptoms recognized and pointed out to them by other DH patients.
DH is not an allergic reaction; a different mechanism is involved. It is caused by antibodies to the gluten found in wheat, rye, and barley.
The causes of DH flares include large quantities of iodides (some iodine is needed in the diet), kelp, shellfish, non-steroidal anti-inflammatory agents (such as aspirin), gluten, stress, and some cleansers.
What else looks like DH?
- DH can be misdiagnosed as psoriasis, or the patient may have both conditions.
- Linear IgA disease--the immunofluorescence pattern is different, but it looks and feels the same as DH to the patient.
- Allergic contact reactions.
DH is treated by adherence to a gluten-free (gluten-free) diet. The skin lesions can be treated with either a sulfone (Dapsone) or sulfonamide(Sulfapyradine) drug. In about 85% of the cases, at least a year on a strict gluten-free diet is needed before DH is resolved. In rare cases DH lesions clear up after only a few weeks on the gluten-free diet.
Dapsone can have side effects, though these are not common. It can alter blood chemistry, causing anemia. Those of Mediterranean or African ancestry can have sudden red blood cell count drops [known asG6PD Deficiency--Dr. Alexander]. Other complications include tingling fingers and neurological problems.
Ideally, if the patient is on medication there would be monthly lab tests to monitor the dosage and effect on the patient. This almost never happens.
The gluten-free diet takes a long time to bring DH under control because it requires time to clear the IgA and IgG from the blood. So even if one is on a gluten-free diet and/or taking Dapsone, technically one has DH. Like an alcoholic, one always has the disease.
Dr. Papp concluded his presentation by answering a few questions from the audience:
Q: How soon after ingesting gluten or iodine will a flare occur?
A: It varies tremendously. With iodine, it usually takes several days of consumption before a flare occurs.
Q: What effect does stress have on a DH patient?
A: It intensifies any symptoms the patient is experiencing.
Q: What effect does iodine on the skin have?
A: It really has no effect; it doesnt penetrate enough. Iodine must be consumed to cause a DH flare.
Q: After several years on a gluten-free diet with no flares, is iodine still a problem?