Category: Food Allergies; Treatments
Frequently, I am asked about the difference between wheat allergy, celiac disease and gluten sensitivity. This is a complicated issue that has many different components. Gluten is a protein that is found in foods that have been processed from wheat and related grains including barley and rye. The diseases listed above represent distinct abnormal responses to either gluten or wheat.
Classic wheat allergy is closely related in pathogenesis to other classic food allergies, like peanut allergy. These conditions are termed IgE-mediated diseases because of the specific type of immune response that leads to symptoms. Other examples of IgE-mediated diseases include hay fever (allergic rhinitis) and some types of eczema and asthma. The symptoms of a classic wheat allergy may include hives or skin rash, vomiting, diarrhea, stuffy/runny nose, sneezing, wheezing, throat constriction or shortness of breath. These symptoms almost always occur within 2 hours of ingesting wheat. Large-scale studies of wheat allergy in the U.S. have not been conducted, but it’s estimated that approximately 0.4 – 0.5% of our population is allergic to wheat. Wheat allergy is typically outgrown by adulthood in about 65% of children. In terms of diagnosis of classic wheat allergy, there are both blood and skin tests that measure wheat IgE. The accuracy of these tests is moderate at best, so we sometimes have to perform food challenges (asking the patient to ingest wheat in a safe controlled environment like the clinic) to really determine if they have classic wheat allergy. If someone is truly wheat allergic, then strict avoidance of wheat is the cornerstone of management as well as treating any accidental ingestions with subsequent reactions appropriately (if severe reaction, epinephrine is used).
Celiac disease is a condition in which the immune system responds abnormally to gluten, which can cause damage to the lining of the small intestine. Celiac disease is also known as gluten sensitive enteropathy, celiac sprue and nontropical sprue. The abnormal response of the immune system in this disease is completely separate than that of classic wheat allergy. Because of this, the symptoms are different and the way we diagnose this disease is distinct. Prototypical symptoms of celiac disease include diarrhea, weight loss, abdominal discomfort or excessive gas. Because this disease in based in the gut, malabsorption can also be seen and lead to other diseases including osteopenia/osteoporosis and iron deficiency anemia. Other associated diseases can include diabetes mellitus, thyroid problems (usually hypothyroidism), dermatitis herpetiformis (intensely itchy, blistering skin rash that affects 15 – 25% of people with celiac disease), nervous system disorders and liver disease. Diagnosis of celiac disease consists of either a blood test and/or small bowel biopsy (the latter being the gold standard test). Both of these tests require that the patient continue eating a normal diet, including foods that contain gluten, at the time of sample collection. The cornerstone of treatment for celiac disease is complete elimination of gluten from the diet for life. Gluten is not only contained in the previously mentioned grains; it is also hidden as an ingredient in a large number of prepared foods, as well as medications and supplements. There are many on-line resources to help patients find safe foods and products, but it can be very difficult. Unlike classic wheat allergy, where the patient only needs to strictly avoid wheat, in celiac disease the patient must avoid all gluten containing products like wheat, rye and barley as well as many processed foods.
Gluten sensitivity is a different reaction to ingesting gluten. Symptoms can arise throughout the body and range from bloating, abdominal discomfort, pain or diarrhea to headaches and migraines, lethargy and tiredness, ADHD, muscular disturbances, neurologic symptoms as well as bone and joint pain. A study from the University of Maryland Center for Celiac Research shows that gluten sensitivity is a different clinical entity versus celiac disease. A different immune mechanism, the innate immune response, comes into play in reactions of gluten sensitivity, as opposed to the long-term adaptive immune response that arises in celiac disease. Researchers believe that gluten sensitive reactions do not engender the same long-term damage to the intestine that untreated celiac disease can cause. These same researchers believe that this disease affects up to 6% of the population (but it is unclear to me how they come about determined this figure.) There is no direct test for gluten sensitivity. The only “test” is a trial of a strictly gluten free diet. I recommend to my patients to try this for one month to see if their symptoms improve. After that month, reintroduce gluten. If the symptoms decrease on the gluten-free diet and the re-emerge upon reintroduction, then gluten may very well be the cause. As with celiac disease, the only treatment is to strictly avoid gluten. For those who are interested in a more detailed, medically oriented analysis of the data please click here.
I hope this helps clear some of the confusion on what gluten is and what the differences are between classic wheat allergy, celiac disease and gluten sensitivity. As always, you can also follow us on Facebook and Twitter for daily pollen counts, office information, patient education and more. If you enjoyed this post please “Like” us on Facebook.
Dr. Ananth Thyagarajan (Dr. T.)