Wheat allergies are the result of an overly sensitive immune system. Instead of recognizing wheat as the harmless substance it is, the immune system of someone with allergies thinks wheat is dangerous and tries to fight it off as it would invading bacteria. The allergens in wheat that your immune system reacts to are usually one or more of four proteins found in wheat: albumin, globulin, gliadin and gluten. When your body detects one of these "invaders," it sends out an antibody called immunoglobulin E to fight them off. The side effects of the battle between your body and the allergen are allergic symptoms.
Among the symptoms of a wheat allergy are rashes of various types -- particularly itchy ones and hives. Hives are red, swollen and itchy bumps that show up on your skin in conjunction with wheat consumption. You can treat an allergy-induced rash or hives with antihistamines and some topical ointments.