A wheat allergy is an allergic reaction that occurs when food containing wheat is eaten, for example bread, cakes, beer, etc.. If you have a wheat allergy, your immune system mistakes these foods containing wheat as harmful, which causes your immune system to react adversely and trigger a chain of events and symptoms.
Allergic reactions to wheat and other cereals are most common in infants and usually resolve within the first few years of life. If you have a food allergy, eating a tiny amount of the offending food can cause a severe reaction, often within minutes, and can be life-threatening. A standard blood or skin-prick test can tell you if you have a wheat allergy, but cannot show whether you have wheat intolerance or not.