An allergy occurs when the body's immune system overreacts to normally harmless substances. It causes symptoms and disease to a person prone to it, which can cause inconvenience, or a great deal of misery. It aggravates the sense of smell, sight, tastes and touch causing irritation, extreme disability and sometimes fatality.
Allergic reactions are caused by substances in the environment known as allergens. An allergic person's immune system believes allergens to be damaging and so produces a special type of antibody (IgE) to attack the invading material. This leads other blood cells to release... From:
8 Common Allergens
