An allergy is an abnormal reaction to an ordinarily harmless substance or substances. These sensitizing substances, called allergens, may be inhaled, swallowed or come into contact with the skin. When an allergen is absorbed into the body, it triggers white blood cells to produce IgE antibodies. These antibodies attach themselves to mast cells causing a release of potent chemical mediators such as histamine; this causes typical allergic symptoms. A person who has allergies doesn't have a poor immune system, rather, they have an over-protective one. Their immune system fights the allergen when it comes in contact with it even though the allergen isn't harmful.
             To diagnose allergies, a physician will clean the person's back with alcohol, then mark it with an ink pen according to each substance going to be tested. They are extracts of potential allergens in small vials. A drop of these is put on the corresponding mark on your skin, and then a needle is used to prick the skin. It breaks the surface of the skin so that the extract can enter. If an extract provokes an allergic reaction, the patient will develop an irritation that may look like a mosquito bite. The ones which promote reactions are the ones in which the person is allergic to and needs to get medication for.
             Allergies are quite common. An estimated 50 to 60 million Americans (about one of every five adults and children) suffer from allergies, including allergic asthma. Allergies are the sixth leading cause of chronic disease in the United States. More than 35 million Americans suffer from seasonal allergic rhinitis, for instance, and this is only one form of allergy. Millions more suffer from food allergies, allergies to medications, and even contact dermatitis (a type of allergic reaction that occurs when your skin comes into contact with an irritating substance).
             Allergies have a genetic component. If only one parent has allergies, chances are one in t...