Wheat allergy

Wheat allergy is an allergy to wheat that typically presents as a food allergy, but can also be a contact allergy resulting from occupational exposure. The exact mechanism of this allergy is not yet clear. Wheat allergy may be immunoglobulin E-mediated or not, and may involve a mast cell response. Wheat allergy is rare—its prevalence in adults was estimated to be 0.21% in a 2012 study in Japan.

Wheat allergy may be a misnomer. There are many allergenic components in wheat (for example: serine protease inhibitors, glutelins and prolamins), with different responses attributed to different components. Twenty-seven potential wheat allergens have been identified.

The allergy, or allergies, are often caused by reactions to the storage proteins present in a wheat seed. While many reactions are caused by wheat proteins, allergenic components are also present in other biochemical forms. The most severe response is wheat-dependent exercise-induced anaphylaxis (WDEIA). WDEIA is attributed to an omega gliadin, which happens to be a relative of the protein that causes celiac disease. Symptoms include nausea, urticaria, and atopy.

Gluten sensitivity and Coeliac disease are two different diseases; however, the management is similar. Management of wheat allergy consists of complete withdrawal of any food containing wheat or other gluten-containing cereals.

Most wheat allergens are proteins, including seed storage proteins, as noted above. There are four major classes of seed storage proteins: albumins, globulins, prolamins and glutenins.

The relevant prolamins in wheat are gliadins. Gliadins and glutenins form the classic glutens—the causative agents of celiac disease (CD). Distinct immune cells and antibody types differentiate gluten allergy from CD (see Comparative pathophysiology of gluten sensitivities).

Prolamins (gliadins) are associated with the more severe form of gluten allergy. Glutenin-induced allergies are often less severe.^{[citation needed]} A proteomics-based study found a γ-gliadin isoform gene.

Glutenin (wheat glutelin) is a predominant allergen in wheat. Nine subunits of LMW-glutenin have been found to be in connection with wheat allergies.^{[clarification needed]}