Wheat AllergyWhat is wheat allergy?
Wheat allergy refers specifically to adverse reactions involving immunoglobulin E (IgE) antibodies to one or more protein fractions of wheat, including albumin, globulin, gliadin and glutenin (gluten). The majority of IgE-mediated reactions to wheat involve the albumin and globulin fractions. Gliadin and gluten may also induce IgE-mediated reactions rarely.
Allergic reactions to wheat may be caused by ingestion of wheat-containing foods or by inhalation of flour containing wheat (baker's asthma).
How common is wheat allergy?
There are no accurate figures for prevalence of wheat allergy. Clinical experience suggests that wheat allergy is relatively uncommon. However, it may be more common in certain subgroups e.g. wheat allergy is responsible for occupational asthma in up to 30% of individuals in the baking industry.
What are the symptoms of wheat allergy?
Allergic reactions to wheat (IgE-antibody mediated) usually begin within minutes or a few hours after eating or inhaling wheat. The more common symptoms involve the skin (urticaria, atopic eczema, angioedema) gastrointestinal tract (oral allergy syndrome, abdominal cramps, nausea and vomiting) and the respiratory tract (asthma or allergic rhinitis). Ige-mediated reactions to gliadin or gluten can cause urticaria, angioedema or life-threatening anaphylaxis in association with exercise. Other gluten-containing cereals (rye, oats and barley) may also cause these symptoms due to cross-reactivity of the allergens.
How is wheat-allergy diagnosed?
The diagnosis may be easy if a person always has the same reaction after eating wheat-containing food or eats wheat infrequently. But more often the diagnosis is difficult because wheat is a staple food. Diagnosis usually entails clinical evaluation (medical history, family history, food history) supported by appropriate laboratory tests (RAST, skin prick-testing). Elimination-challenge testing remains the most reliable method of diagnosis.
How is wheat allergy treated?
Avoidance of wheat and wheat-containing foods is the first step in the treatment of wheat allergy. (Table 1) However, because wheat is a staple food product, wheat elimination diets are particularly difficult for a patient and his/her family to maintain. Children on wheat-restricted diets are severely limited in their selection of foods. Alternatives may be found in special health shops. Treatment must be supervised by a dietician - provides wheat-free recipes and ensures nutritionally adequate diet. Wheat allergic patients who have sensitivity to gluten (or gliadin) should avoid other gluten containing cereals such as oats, rye and barley.
Table 1. Label ingredients that indicate the presence of wheat proteins
- Bread crumbs
- Cereal extract
- Cracker meal
- Enriched flour
- High-gluten flour, high-protein flour
- Semolina wheat
- Vital gluten
- Wheat bran, wheat germ, wheat gluten, wheat malt, wheat starch
- Whole wheat flour
Label ingredients that may indicate the presence of wheat protein
- Gelatinized starch
- Hydrolyzed vegetable protein
- Modified food starch, modified starch
- Natural flavoring
- Soy sauce
- Vegetable gum, vegetable starch
Copyright: Allergy Society of South Africa.
Written by Dr C. Motala
Endorsed by ALLSA.
This information sheet is obtainable from:
P.O. Box 88
Cape Town, R.S.A.