The etiology and pathogenesis of wheat allergy varies depending on the specific allergy trigger.
IgE mediated wheat allergy
The exact protein or proteins involved in triggering wheat allergy are not always clearly identified. However, three specific types of IgE antibody mediated wheat allergies have been described in medical literature.
Baker’s asthma
Bakers’ asthma; results from inhaling wheat flour or wheat dust. The a-amylase/LPTs are the main wheat proteins involved in this reaction [1].
Wheat dependent exercise induced anaphylaxis (WDEIA)
WDEIA, is caused by a reaction to the omega 5-gliadins (part of the gluten protein fraction). These individuals may not react to the ingestion of wheat by itself. However, exercise can induce changes in the body that either trigger an allergic reaction or exacerbate an immune response to wheat. The exercise induced reaction occurs when the individual exercises shortly after or ingesting wheat or ingest wheat while exercising. An anaphylaxis reaction can occur when the two are combined.
Lipid transfer proteins
This type of wheat allergy is caused by the lipid transfer protein in wheat and the reactions can range from milder to more severe symptoms [2].
Non-IgE mediated/mixed IgE and non-IgE mediated wheat allergy
Non-IgE mediated wheat allergy has been less well defined. In the USA [3] non-IgE mediate food allergy is classically considered to be reactions related to protocolitis, food protein induced enterocolitis [1] or food protein induced enteropathy (including celiac disease). In the UK and Europe, non-IgE mediated food allergy is more loosely described with a variety of symptoms not charactized by IgE production (see table below). Eosinophilic disease or eczema is considered to show a mixed pattern of both IgE and non-IgE mediated mechanisms.
Symptoms of IgE mediated food allergy
| IgE Signs and Symptoms | Non-IgE Signs and Symptoms | |||
|---|---|---|---|---|
| minutes after food ingestion (But may be up to 2 hours) | Usually hours or even days after food ingestion | |||
| Skin | Skin | |||
| • Pruritus | • Pruritus | |||
| • Erythema | • Erythema | |||
| • Acute urticaria ( localized or generalized) | • Atopic eczema | |||
| • Acute angioedema (most commonly of the lips, face, or around the eyes) | ||||
| • Acute flaring of Atopic eczema |
Wheat intolerance
Wheat intolerance presents with a variety of different symptoms and from diverse physiologic pathways (gastrointestinal, neurologic, etc). Symptoms are usually delayed, often two to 3 days after ingesting the offending food. Due to the ubiquitous use of wheat and the long time to onset of symptoms, wheat intolerance is difficult to define the trigger. The reactive component may relate to the FODMAP content of wheat, or other components of the grain.
References
- Nam YH, Hwang EK, Jin HJ, Lee JM, Shin YS, Ye YM, Palacin A, Salcedo G, Lee SY, Park HS. Comparison of specific IgE antibodies to wheat component allergens in two phenotypes of wheat allergy. J Korean Med Sci. 2013 Nov;28(11):1697-9.
- Constantin C1, Quirce S, Poorafshar M, Touraev A, Niggemann B, Mari A, Ebner C, Akerström H, Heberle-Bors E, Nystrand M, Valenta R. Micro-arrayed wheat seed and grass pollen allergens for component-resolved diagnosis. Allergy. 2009 Jul;64(7):1030-7.
- Boyce JA, Assa’ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID- sponsored expert panel. J Allergy Clin Immunol 2010; 126:S1 – S58.
- National Institute for Health and Care Excellence. Diagnosis and assessment of food allergy in children and young people in primary care and community settings. Clinical Guideline CG116. London: 2011. guidance.nice.org.uk/CG116