Wheat Allergy Due to Cross-Reactivity with Grass Pollen

When I initially began researching wheat allergy, I knew that there was an association between allergy to grass pollens and positive IgE testing to the wheat protein. I had read that low positive results on the wheat food IgE tests are rarely clinically significant in those with grass pollen allergies. I ended up requesting grass pollen allergy tests from my allergist to see if this association existed for me. I knew that I reacted somehow to grasses. If I didn’t wear a mask when mowing the grass during the spring, I would experience nasty symptoms for the next few days. I would always take Benadryl before bed in those cases to calm things down and help me sleep. Every grass pollen that was tested at that time, including cultivated rye, came back at Class IV or higher. Did this mean that the

wheat food IgE test result that I had at the beginning of the year was truly a false positive as suggested by the allergist who ordered it? I knew that I had some kind of allergic reaction to wheat, and I was interested in finding out if there might be another explanation for my reactions, especially considering the high positive predictive value for wheat, which can be as high as 26 kU/L. By comparison, my result was never higher than 0.5 kU/L. I ended up finding out about more wheat IgE tests, called component tests, that test for specific wheat proteins that are not known to be cross-reactive. If someone has positive results to any of these, he or she has a true allergy to wheat. My allergist could not order these tests, but he ordered cultivated wheat and wild rye grass pollen tests. I continued to research, and when I went to pick up the orders for the tests, I requested another appointment with my allergist. I had one scheduled for a couple of weeks later. During the time leading up to the appointment, the results for cultivated wheat and wild rye grass came back as Class IV.

Over the time I was doing my reading and research, I learned that a person can develop allergies to food due to allergies to pollen. The pollen allergy would be the primary allergy, and the food allergy would result due to cross-reactivity with the pollen. The condition most commonly discussed is oral allergy syndrome (OAS), where reactions to certain proteins in pollen can also cause reactions to raw/fresh fruits, vegetables, nuts, seeds, and spices due to the existence of similar proteins in the foods and the pollen, most commonly profilin. Oral allergy syndrome usually causes symptoms in/around the mouth and throat. Oral allergy syndrome didn’t quite seem to fit. I can eat raw/fresh fruits and vegetables with no issues, and I don’t notice immediate symptoms in my mouth or throat. However, all my reactions are to plant-based foods, wheat (and possibly the other gluten grains), guar gum, and flaxseed. My symptoms upon exposure to wheat/gluten are immediate and obviously IgE-mediated due to the work of antihistamines on my symptoms. Flaxseed symptoms, although it’s been years since the last time I had them, were pretty immediate but not as quick as after exposure to wheat. I’m also not sure if those symptoms would have responded to antihistamines. I never noticed issues with guar gum until the following day and again had never tried antihistamines to relieve them. Although all cause gastrointestinal symptoms, I would get fatigue and dizziness upon exposure to wheat. None of these seemed typical of oral allergy syndrome. However, I continued to try to find any information I could on the connection between my grass pollen allergies and my reactions to wheat. I did find a couple of articles that discussed reactions to wheat in relation to OAS.

Gluten Intolerance School: Oral Allergy Syndrome
Poor and Gluten Free: Oral Allergy Syndrome

However, I still wondered if there might be something else. I finally found this article, which mentioned another protein in grass pollen that could cause the food reactions to wheat, called a beta-expansin, “Cross-reactivity between aeroallergens and food allergens”.

Although several patients with oral allergy syndrome, urticaria, angioedema, gastrointestinal or anaphylaxis symptoms after ingestion of products containing wheat or maize flour were reported in patients suffering from respiratory allergy to grass pollens, cross-reactivity among cereal grains and grass pollen is generally considered clinically insignificant. Beta-expansin 11 (EXPB11), a homologue of the major allergen of timothy grass pollen, Phl p 1, may bear a high cross-reactive potential in patients who suffer from both food allergy and pollinosis.

Things then started to make more sense. Perhaps the beta-expansin protein was the connection I was looking for. I went to my allergist appointment armed with all this information. I was hoping he would take the idea that my grass pollen allergies were causing my allergic reactions to wheat seriously.

The appointment with my allergist ended up going really well. He agreed, based on my test results, that my reactions to wheat were due to cross-reactivity with grass pollens. He said that low, inconclusive, or negative IgE tests to foods are common with pollen cross-reactivity. He also did skin tests for timothy grass, bermuda grass, ragweed, and birch pollen. I had avoided antihistamines for the eight days leading up to my appointment in case he wanted to do any skin-testing, and I’m glad I did. The nurse just pricked me on the inside of my forearm at first, but those results were negative. She later brought in needles that contained the extracts and injected them just under the skin on my arm near my shoulder. This particular test brought forth different results. I got the highest result possible for timothy grass, bermuda grass, and ragweed. Birch was still negative. This test caused my head and neck to itch, and I had to take Benadryl and Zantac later on to relieve the itching. After the results of the test were determined, the doctor came back into my room, and he discussed the possibility of allergy shots. Sometimes, immunotherapy for pollens can also have a positive affect on the food reactions. It may be possible to lessen reaction symptoms and in some cases even reintroduce the food(s). Since celiac disease is still a question, I would not want to reintroduce the gluten grains without knowing for certain that I do not have celiac disease. My gastroenterologist believes my tests were falsely negative. There is a new celiac disease blood test in development, mentioned at the beginning of this article, “How is Celiac Disease Diagnosed?”, that could become available during the time I could be potentially undergoing immunotherapy. I’m highly interested in seeing if the shots help me, if they would cause my IgE levels to drop. If I can have the new celiac disease test done, and if it turns out to be negative, then perhaps I could discuss with my allergist the possibility of a food challenge with the gluten grains to see what happens if my IgE levels decrease significantly. If the celiac disease test is positive, or if I can’t handle eating the gluten grains, then perhaps the immunotherapy would at least be good for my hypersensitivity. For example, maybe I could unwrap a Snickers bar and eat it with my hands without having to wash down both my hands and the package first. Of course, determining how far I can go will have to involve discussions with both my allergist and my gastroenterologist.

I finally feel like I’m closing in on an answer to all the issues and struggles I’ve dealt with and gone through over the last four years. While celiac disease at this time still remains a possibility, it’s good to have a tested and doctor-verified condition after all this time. I just wish that the two allergists I’ve seen had thought about the possibility themselves and tested me for it instead of me having to do all the digging and research and bring it up. It seems like my inconclusive IgE test results coupled with my strong history of reactions to wheat ought to have at least suggested the possibility. However, I’m glad my current allergist has been willing to work with me and order the tests that I request, in order to get to the root of what’s going on with my reactions to wheat at least.

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