A long-term form of allergy treatment involving gradual exposure to small doses of allergens over a period of several years. Also known as immunotherapy and allergy shots.

Desensitization is a form of allergy treatment that involves the periodic injection of small amounts of allergens over a period of several years. Allergens such as dust and pollen cause certain people to produce elevated levels of immunoglobulin E (IgE) antibodies, which in turn unleash chemicals called histamines that produce allergic reactions. By introducing allergens into the body in a highly diluted form, desensitization is designed to increase the immune system's tolerance to these substances so that they no longer cause such allergic reactions as asthma, sinus congestion, sneezing, and red, watery eyes. Allergy shots are effective for many of the approximately six million Americans who receive them regularly. However, the desensitization process is long, time-consuming, and expensive and doesn't work...