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Questions & Answers
Question: I have been diagnosed with CD and DH. My doctor has prescribed Dapsone which I have been using for 10 years. I follow a strict GFD. What are the long term effects of taking Dapsone? Given that I am following a strict GFD, why have my symptoms of DH not disappeared after this length of time while my GI symptoms have?
Answer: Dapsone is an extremely useful drug for the treatment of DH. The most dramatic and gratifying response occurs when the horrendous itching of DH clears within 6-36 hours of taking Dapsone. A GFD alone would entail several more days to weeks of itching before obtaining relief. The rash takes even longer to dissipate.
Dapsone should always be prescribed concurrently with a GFD because this drug does not improve intestinal damage. Dapsone blocks the acute inflammatory process in the skin lesions, but does not affect the chronic IgA granular skin deposits needed to diagnose DH using skin biopsies. These deposits may not disappear for two or more years after starting a GFD.
There is considerable individual variation in reaction to the effects of DH and the response to therapy. Usually the rash is controlled using 25-100 mg of Dapsone daily, but some patients require more. Two years is the average duration of therapy required (including a GFD, of course). In one study, half of the patients still needed a low dose of Dapsone for longer than ten years despite adherence to a GFD. It is estimated that 10% of DH patients are exquisitely sensitive to gluten and associated DH flare ups, and although poor dietary compliance is believed most often responsible, other triggers may be operative. Triggers under consideration are iodine and iodized salt and seaweed (sushi), as well as nonsteroidal anti-inflammatory drugs such as aspirin and ibuprofen.
Whether Dapsone therapy is used or not, DH is treated with a GFD for life.
Anyone receiving Dapsone therapy requires physician monitoring and dosage adjustments. Before prescribing Dapsone, a blood test to exclude glucose-6-phosphate dehydrogenase (G6PD) is necessary because Dapsone can induce hemolytic anemia in this and other genetic red blood cell abnormalities. Headaches may occur in those taking daily doses of 100 mg or more. Severe hypersensitivity reactions are rare and usually occur during the first few months of treatment. An exception is the risk of peripheral neuropathy developing after long term treatment using high daily doses of Dapsone. Presenting symptoms may be numbness and tingling, and pain and weakness in the extremities. Vitamin B12 deficiency would need exclusion as a contributing factor to peripheral neuropathy.
Question: I have celiac disease and a nephew of mine has suffered from severe psoriasis since he was a teenager. Is there a possibility that a gluten-free diet could be helpful to him?
Answer: Dermatitis herpetiformis (DH) is the skin expression of celiac disease(CD). Many gastroenterologists, however, have biopsy-proven celiac patients with recurrent skin rashes that respond to the gluten-free diet(GFD). These rashes usually are neither suggestive nor compatible with typical DH, e.g., chronic urticaria (recurrent hives).
Since CD is so common (1 in 100-150), as is psoriasis, it is inevitable some individuals with skin diseases other than DH will have coincidental CD. In these cases, a complete response of the dermatitis to a GFD does not constitute proof of this dermatitis being another skin manifestation of CD.
There are several reports of patients having both psoriasis and celiac disease, but there is continuing controversy about an affiliation between celiac disease and skin diseases such as psoriasis, eczema, and chronic urticaria (recurrent hives) A few cases have been reported of the skin condition of patients with psoriasis clearing up within a few weeks to six months after starting a gluten-free diet(GFD). However, such anecdotal evidence does not justify a trial of GFD. In order to determine if a patient has celiac disease they must be on a gluten-containing diet or the blood tests and biopsies will not be definitive.
Screening patients with psoriasis for celiac disease has been suggested by some physicians, although it is not a standard recommendation. I would suggest your nephew ask his doctor to screen him for celiac disease using the endomysial antibody (EMA) and tissue transglutaminase (tTg) tests and a serum IgA level (to exclude false negative results). If these tests suggest the likelihood of celiac disease, small bowel biopsies should be obtained. If your nephew is diagnosed with celiac disease a strict GFD for life will be necessary.
Question: I have celiac disease and am trying to persuade my brother, who has had severe diabetes since he was a teenager, to have blood screening tests for celiac disease. Can you give us any advice regarding this?
Answer: The association between insulin-dependent diabetes mellitus (Type 1) and celiac disease has been recognized for many years. It is estimated that between 5-10% of patients with Type 1 diabetes will develop celiac disease, usually within 10 years of their diagnosis of diabetes. This percentage may be higher if the patient has a first degree relative with celiac disease. Both celiac disease and Type 1 diabetes are associated with the HLA-DQ2 and HLA-DQ8 genes.
Diabetic patients are susceptible to developing symptoms in several body systems often simultaneously, e.g., cardiac chest pain, neuropathy with loss of sensation in the feet, gastrointestinal bloating and erratic bowel function. These gastrointestinal symptoms often mimic those of untreated celiac disease. Testing is required to distinguish between Type I diabetes with and without accompanying CD.
Many, but not all, diabetic clinics and specialists screen for celiac disease in their patients. The most accurate blood tests are the EMA (IgA endomysial antibody and the tTg (IgA tissue transglutaminase antibody). In addition, a serum IgA level should be obtained to exclude false negative results.
If these screening tests suggest the possibility of celiac disease, a small bowel biopsy should be carried out to confirm the diagnosis.
30% of patients with celiac disease have at least one associated autoimmune disorder compared to 3% of the general population. In celiac disease the most common associated autoimmune disorders are Type 1 diabetes and chronic thyroid disease, which further supports the wisdom of screening for celiac disease in these disorders.
Question: My mom was recently diagnosed with celiac disease. She really wants me and my siblings to get tested for celiac disease. Do you think we should? I just read about this celiac home testing kit. Is it available in Canada? Is it reliable? Then I don't need to get a biopsy, right?
Answer: Your mom is right. You and your siblings should get screened to see if you might have celiac disease (CD). First degree relatives of people with CD are at a higher risk of developing it. You can be screened for CD with a simple blood test.
One of the major advances in CD in the last decade has been the development of serological (blood) screening tests. The two currently recommended tests for screening are the tissue transglutaminase antibody (TTG) or endomysial antibody (EMA). These tests are now widely available and are of great help to physicians to screen individuals suspected of having celiac disease.
Both TTG and EMA are highly sensitive and specific screening tests for celiac disease. This means that these tests will be positive in most (about 90%) individuals with untreated celiac disease and will be negative in most people who do not have the disease. However, these are not diagnostic (confirmatory) tests for celiac disease. There could be instances in which a person who has celiac disease has a negative test. Similarly, rarely but possibly one could have a positive test and not have celiac disease. Of note, these serological tests are less reliable in infants and young children and tend to become negative after starting a gluten-free diet.
A small intestinal biopsy is the definitive test to diagnose celiac disease. The biopsy enables the physician to examine specific changes in the mucosa (lining) of the small intestine that occur from gluten ingestion in individuals with celiac disease. The treatment of celiac disease is a life-long adherence to a gluten-free diet. Such a diet is costly, complicated and challenging especially when it has to be followed strictly and forever. Removal of gluten often leads to rapid healing of the intestinal mucosa. Therefore, if an individual does not have biopsy-confirmed celiac disease and goes on a gluten-free diet based on symptoms alone or a positive blood test, a subsequent intestinal biopsy can be very difficult to interpret as it may appear normal. The diagnosis will then remain doubtful.
Recently, over-the-counter home celiac blood testing kits have been developed and have hit the Canadian market place. At this time, there is limited data available on the accuracy of these home-testing kits. Since a positive or negative blood test does not confirm or rule out celiac disease with certainty, caution needs to be exercised in using and interpreting these tests. A consumer who wants to utilize this test should be aware of its limitations.
It is highly recommended that a gluten-free diet NOT be started based on a positive blood test alone. A positive blood test should be discussed with one's physician and a small intestinal biopsy arranged to confirm the diagnosis of celiac disease.
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