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Wheat Allergy

Many people complain of reactions to wheat, but most of these are not actually wheat-allergic – they are either wheat intolerant or may have coeliac disease.

Many people think the terms food allergy and food intolerance mean the same thing; however, they do not. Food intolerance is a reaction that does not involve the immune system. A food allergy is a reaction that involves the immune system (see “What is an allergy?”). The difference is important because food allergy can range from mild reactions to severe, life threatening (anaphylactic) reactions and can occur even with tiny doses. Food intolerances are not life threatening and the person may be able to eat small amounts of the food, but have symptoms on eating larger amounts.

What wheat reactions can occur?

  • Wheat allergy occurs when a protein in wheat (albumin, globulin, gliadin or glutenin / gluten) causes allergic reactions. The immune system treats one or more of these proteins as a danger to the body and starts an allergic reaction when the proteins are eaten, touched or in some cases inhaled (baker’s asthma)
  • Wheat intolerance is not triggered by the immune system and cannot be diagnosed with standard allergy tests (such as blood or skin tests). It affects the digestion; common symptoms include stomach pain, diarrhoea and bloating after eating too much wheat
  • Coeliac disease is a response by the immune system but is not an allergic response; it is a condition where gluten proteins found in wheat and some other cereals damage the small bowel lining and the gut (see “Coeliac disease” brochure).
How common is wheat allergy?
  • Wheat allergy is much less common than milk, egg and peanut allergy.
  • Wheat intolerance is much more common than true allergy.
  • Wheat allergy may occur in adults, but is usually outgrown in childhood.
  • It is more common in people who work with wheat in the baking industry.
Symptoms of wheat allergy
  • The most common type of wheat allergy is “immediate” type (IgE-mediated) food allergy (see Food allergy)
  • This type of reaction typically occurs within minutes but may present up to 2 hours after eating the food.
  • Most allergic reactions to wheat are mild, causing hives (urticaria), swelling or vomiting. Some allergic reactions can be severe, causing difficulty in breathing due to throat swelling or asthma, or a drop in blood pressure. This is known as anaphylaxis.
  • In some patients, reactions to wheat can be worse with exercise, or occur only with exercise.
  • People with wheat allergy can have reactions to other cereals (rye, oats and barley) because of cross-reactivity between the allergens.
  • Less commonly, wheat allergies may be of the delayed type (non IgE-mediated) allergy, with abdominal symptoms (diarrhoea, bloating, cramps) or eczema hours to days after the intake of wheat (see “Delayed type food allergy”)
How is wheat-allergy diagnosed?
  • The first step is for the doctor to hear all the details about what was eaten and exactly what reactions occurred. This will help indicate whether the reaction was an allergy or not and if it was an allergy, what kind of reaction it was and whether it was mild or severe.
  • The diagnosis may be easy if a person always has the same reaction after eating wheat-containing food or eats wheat infrequently. More often the diagnosis is difficult because wheat is a staple food and often a “hidden” ingredient in food.
  • For immediate reactions a blood test and/or skin prick tests can be done to show the presence of the ige antibodies. If these tests are negative an immediate type allergy is almost always ruled out. A “positive” result supports, but does not prove an immediate type food allergy, unless the values are very high.
  • Skin prick tests are done by placing a few drops of specially manufactured wheat extract on the skin and making a prick through the droplet (see “skin prick testing”).
  • Remember that a positive skin or blood test alone is not enough evidence for a wheat allergy and can be misleading.
  • Many people with allergy to grass pollen have a positive skin-prick test to wheat, because of cross-reactions between wheat and grass pollen. This means that a “positive” wheat test in someone with grass allergy might not actually mean wheat allergy at all!
  • Wheat allergy tests should be interpreted by a specialist taking into account the history and the test results.
  • In cases which are uncertain, the allergist may recommend a supervised food challenge to test for wheat allergy. This entails giving initially tiny, then increasing amounts of wheat to the person in a controlled setting (see oral food challenge tests).
  • Specialised blood tests for parts of the wheat protein (called omega- 5 gliadin) are also available and indicate the allergy is more likely to be a true allergy.
  • For delayed type (non-ige mediated) allergies to wheat, the diagnosis is made by improvement of symptoms when wheat is removed from the diet, and worsening of symptoms when it is reintroduced (elimination-challenge test).
Treatment of wheat allergy
  • If you allergic to wheat, you must avoid eating bread and all wheat products.
  • Wheat allergic patients should look out for the label “wheat free” and not just “gluten free” (as gluten is only one of many wheat proteins)
  • Because wheat is a staple food product, wheat elimination diets are particularly difficult to maintain.
  • Children who are avoiding wheat have a much smaller selection of foods available. Avoiding foods is difficult! A dietician experienced in managing food allergy will provide advice, recipes and education on how to achieve a nutritious and complete diet.
  • Wheat allergic patients who have sensitivity to gluten (or gliadin) should avoid other gluten containing cereals such as oats, rye and barley.
Emergency Treatment
  • Wheat is very difficult to avoid completely, and most wheat allergic people will have an accidental reaction at some stage.
  • Caregivers in schools, family members and friends should know about the allergy and what to do in an emergency. A detailed “action plan” should be provided in case of reactions. This should clearly describe the difference between mild and severe reactions as well as what to do if different types of reactions occur. The action plan should be highly visible at home and in the school/work environment. Action plan (picture)
  • The patient should have access to their emergency treatment at all times. For milder reactions an anti-histamine may be enough. For severe reactions, injectable adrenaline will be needed.
  • The allergy doctor should decide on whether a person with allergy is at risk to have a severe reaction. People with previous severe reactions or at risk of severe reactions should carry injectable adrenaline with them at all time, preferably in the form of an auto-injector.
  • People who have been prescribed an autoinjector must be trained when and how to use it and carry it with him/her at all times.
  • Wheat allergic individuals should wear a medic alert or similar bracelet, especially if they have a severe allergy or also have asthma.
Action plan

Which foods contain wheat?

Wheat is a main ingredient of many foods such as:

  • Breads, chapattis and naan breads, breakfast cereals, biscuits, crackers, crumpets, scones, pancakes, wafers, cakes, pizza, pasta, pastries and yorkshire puddings.
  • It is also found in many convenience foods such as soups, sauces, spices, malted drinks, processed meats and ready- made meals.
  • Some alternatives which may be used instead of wheat include:
  • Rice grains/flakes/flour
  • Potato flour
  • Sago
  • Buckwheat flakes or flour
  • Corn, corn flour, Maize, Polenta
  • Millet grains/flakes/flour
  • Quinoa
  • Soy flakes or flour
Download our “Wheat allergy” leaflet for free