Dermatitis herpetiformis (DH) is a gluten-sensitive disease related to celiac disease. DH is characterized by intensely itching blisters which are symmetrically distributed on the trunk, buttocks, elbows, knees, neck, or even the scalp. The close relationship is confirmed by the fact that 80 to 90 percent of patients with DH also have gluten-sensitive enteropathy, although the damage to the villi is usually less severe than in people with celiac disease and in perhaps 80 percent will be asymptomatic.
A new unscratched lesion is red, raised, and usually less than 1 cm in diameter with a tiny blister at the center. However, if scratched, crusting appears on the surface. The "burning" or "stinging" is different from a "regular" itch and can occur 8-12 hours before a lesion appears. As the blisters dry up, they form scabs.
Diagnosis is through immunofluorescence staining on a skin biopsy taken near a group of blisters, not from the blister itself. In patients with DH, the test will show IgA antibodies in the skin.
Treatment of DH is by drugs and diet restrictions. Sulphones (dapsone or sulfapyridine) are used to treat the symptoms of DH. The response is dramatic. Within 24-48 hours the burning is relieved and the rash starts to disappear. The aim is to use the smallest dose possible to keep the itch and rash under control as these drugs may have unpleasant side effects.
The patient with DH who also goes on the gluten-free diet is addressing the cause of the blisters, not just treating the symptoms. Treatment with the gluten-free diet may show good effects within 2 to 3 months as symptoms decrease and the amount of dapsone needed is reduced. Patients with DH are advised to maintain a strict gluten-free diet for life.
By Deborah Holladay
When compared with the average time it takes for a celiac to be correctly diagnosed – 10 years – the six months that it took for me to be diagnosed with dermatitis herpetiformis (DH) was remarkably quick. I would say that I was extremely lucky, but my good fortune was actually in the fact that my younger sister was diagnosed with DH more than ten years before I ever had symptoms. Knowing what her DH rash looked like was a valuable tool in my diagnosis.
I was taking allergy shots when I broke out with the initial rash, and of course, my first thought was that the allergy shots had triggered some kind of reaction. However, none of the staff at the allergy clinic had ever seen anything like the rash, which first presented on my knees, and they sent me to my primary care doctor.
By the time I was able to get an appointment with the primary care doctor, I had become quite itchy, with the rash now breaking out on my elbows. Also, it was beginning to look suspiciously like my sisterís DH, which was precisely what I told my doctor. As the primary care physician had no idea what DH was, he referred me to a dermatologist. Meanwhile, he noted that I was quite anemic and started me on megadoses of iron and folate.
The first dermatologist told me that I couldn't possibly have DH if my sister had it because it was such a rare disease that it would be nearly impossible for two people in the same family to have it. She began treating me for scabies, and I began reading medical textbooks on dermatology. It didn't take long before I discovered that not only did my rash not look like scabies or present in the same places where scabies would normally be found, but I also discovered that DH was genetic. Therefore, for two people in the same family to have it would not be unthinkable.
On my next visit to the dermatologist, I suggested that she biopsy a blister (having just read about that approach), and she reluctantly did so, although she also continued to treat me for scabies until the results of the biopsy returned. When the biopsy returned with the possible diagnosis of DH – and it was only a possible diagnosis since she had done an excisional biopsy and had neglected to treat it with the proper medium for immunofluorescence – she still refused to believe that I could have DH. She wanted to continue treating me for scabies. I made an appointment with a different dermatologist.
The second dermatologist was a teacher and researcher at a medical school in Miami, Florida. (I lived in Florida at the time.) He listened to my family history and my tale about being treated for scabies, took a good look at my elbows and knees, and said it looked as if I had a classic case of DH. He did a punch biopsy of a blister, carefully divided the sample, and sent the two halves to separate labs to get two opinions at once. What a great doctor!
By this time, I was sleeping only a few hours at a time at night because I itched so badly that I woke myself up scratching. My entire body was itching, and nothing provided relief. I was exhausted and yet running in high gear because I couldn't stand to sit still and itch. I spring and fall cleaned my house to keep from scratching. My family practice doctor was concerned and perplexed that my blood count was going down rather than improving, and he began doing other diagnostic tests, such as fecal occult blood tests. He doubled my iron and folate dosage and warned me that if my blood count dropped to a certain level, he would have to consider more drastic measures. At the time, neither he nor I had any idea that the rash that I had was in any way related to my falling blood count.
Fortunately, the biopsy results finally arrived at the office of my dermatologist, and he confirmed that I had DH. He immediately put me on Dapsone and prednisone to give me relief from the itching but also told me that I would have to go on a gluten-free diet. I had no idea what a gluten-free diet was because my sister only took Dapsone for DH. He did not refer me to a dietician, but I was born to do research, and I began reading everything I could find. There was not much information available back then, but with persistence, I was able to learn what I needed to know and make the changes in my diet.
When he diagnosed me, the dermatologist told me that it would probably take 6 months of being on a gluten-free diet before I could get completely off Dapsone, but within 4Ĺ months I was completely off Dapsone and was itch, rash, and blister free. Not only that, but my blood count was back to normal, and I was off the iron and folate therapy.
My family practice doctor was mystified by my improved state but happy. Even more interesting was the fact that after being on the gluten-free diet for the first month or so, I realized that my stomach had been hurting for such a long time that I had not noticed the pain until it quit hurting. The bloating and other mild gastrointestinal symptoms that I had assumed were due to some food allergy but had not showed up in the allergy testing also disappeared. I later figured out that I had been having mild celiac symptoms for nine years before I finally broke out with DH.
Over the past 10 years that I have been eating gluten free, there have been a half dozen or less times that I have had to go on Dapsone for a short period of time when I have had a relapse.
Each time, it has been due to a hidden source of gluten in my diet. Once was when the manufacturers of Hidden Valley Ranch dressing changed their formula so that it was no longer gluten free. That was truly hard for me to detect because I had called the company in the past and gotten their assurance that the product was safe. I never thought about having to check again.
Another time, I was getting small amounts of gluten in a prescription medication. That was far easier to detect because I could ask myself, “What am I doing differently than I normally do?” and the answer was that I had gone on a new medication.
What I have observed over years of experience is that if I get a significant amount of gluten at one time – and it is always completely accidental because I am very careful and don't cheat – I get GI symptoms rather than DH. However, if I get small amounts of gluten consistently over a long period of time, as in the case of the salad dressing, I get a flare of DH. I don't know if that happens to other people with DH or not. I do know that my sister, who finally decided to go off Dapsone and go on a gluten-free diet several years ago, has the same experience.
It was my sister's earlier diagnosis of DH that enabled me to recognize the possibility that I had DH and find a doctor who was familiar with the condition. In turn, it was I who informed my younger sister of the health benefits of maintaining a gluten-free diet rather than controlling the DH rash with Dapsone. We now share information, cookbooks, recipes, and ingredients with each other and with our other sister, who has since discovered that she has celiac disease without DH. Though the three of us may have been unlucky in the gene pool, we have been quite fortunate to have each other.