An allergy develops when a person's body has a bad reaction to a particular substance or product that's normally harmless, such as cow's milk protein or pollens. The substance that causes the allergic reaction is called an allergen.
Allergens can enter the body when they're eaten, touched, inhaled or breathed in.
When the body perceives the allergen as something harmful, it tries to protect itself by by making antibodies which attack the allergen. In the process, the person experiences various allergic symptoms that can range from mild to severe. Allergy testing helps us determine exactly what a person is allergic to by detecting whether a person has developed an antibody against a tested substance such as a specific food, airborne allergen or a medication. A series of drops, each containing a specific antigen, is placed on a child's forearm. Next, with a small needle, the area of skin at each drop is pricked very gently.