The aetiology and pathogenesis of wheat allergy varies depending on the type of allergy present:
IgE mediated wheat allergy
In general, IgE mediated wheat allergy presents with symptoms such as described by the UK NICE guidelines on food allergy (table 1) (9) but the exact protein or proteins involved are not always clearly identified.
However, three specific types of IgE mediated wheat allergies have been described in the past:
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 .
Bakers’ asthma; results from inhaling flour or wheat dust and the main wheat proteins causing this are the alpha amylase or lipid transfer proteins (LTPs) .
Wheat dependent exercise induced anaphylaxis (WDEIA)
WDEIA, is caused by a reaction to the omega 5-gliadins (part of the gluten protein fraction). For these reactions to occur, wheat is often ingested without a problem, but if followed by exercise shortly after or during wheat ingestion, can cause anaphylaxis.
Non-IgE mediated/mixed IgE and non-IgE mediated wheat allergy
Non-Ige mediated wheat allergy has been less well defined. In the USA  non-IgE mediate food allergy is classically considered to be reactions related to protocolitis, food protein induced enterocolitis  or food protein induced enteropathy (including coeliac disease). In the UK and Europe, non-IgE mediated food allergy is more loosely described with a variety of symptoms not charactised 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.
Wheat intolerance presents with a variety of different symptoms, is difficult to define and may relate to the FODMAP content of wheat, or other components of the grain.
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|
|• Pruritus||• Pruritus|
|• Erythema||• Erythema|
|• Acute urticaria (localised or generalised)||• Atopic eczema|
|• Acute angioedema (most commonly of the lips, face, or around the eyes)|
|• Acute flaring of Atopic eczema|
- 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
- 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.
- Venter C and Groetch M. The Nutritional Management of Food Protein Induced Enterocolitis. Curr Opin Allergy Clin Immunol. 2014 Jun, 14, 255-62. (ed Anna Nowak and Alessandro Fiocchi).