What is an Allergy?

The topic of allergies has become routine in our lives, and certainly most everyone has an idea of what an allergy is. Allergies are so common a subject in fact, it seems acceptable to discuss your allergies at a cocktail party with strangers.

An allergy is an abnormal reaction by a person's immune system against a normally harmless substance. A person without allergies would have no reaction to this substance, but when a person who is allergic encounters the trigger, the body reacts by releasing chemicals which cause allergy symptoms. However, just because there is a cause and effect between exposure to a substance and the development of symptoms does not always mean that a person is allergic to that substance. For example, medications have known and expected side effects; a person experiencing one of these side effects is not necessarily allergic to that medication.