allergy Definition

altered bodily reactivity (such as hypersensitivity) to an antigen in response to a first exposure

exaggerated or pathological immunological reaction (as by sneezing, difficult breathing, itching, or skin rashes) to substances, situations, or physical states that are without comparable effect on the average individual

medical practice concerned with allergies

an injection containing very small amounts of an allergen (such as mold or grass pollen) to which an individual is sensitive that is given at regular intervals usually over a period of several years to desensitize the immune system and reduce allergic symptoms

relieving, controlling, or preventing allergic symptoms : anti-allergic