An allergy is any adverse (bad) reaction the body has to a substance that are normally considered harmless where IgE is involved. A substance which causes an allergic reaction is called an allergen; they are said to be 'harmless' as they do not effect those not allergic. An allergic reaction arises when the body fails to recognise the allergen as harmless and responses as if the allergen were harmful and so produces antibodies as part of the immune response. The anitobodies are made up of a protein called immunoglobulin which exists in various forms within the body. Immunoglobulin E (IgE) is the protein associated with allergic response and in people who have suffered an allergic response, elevated levels of IgE can be found (and tested for). The allergy arises when the body comes into contact with the allergen for a second time, as during the first the lymphocyte cell makes the antibodies, so when the allergen enters the body a second time, more antibodies attach themselves to mast cells, located near the skin. The antibodies then bind to the allergen activating the mast cells causing them to break and release histamine, which results in the symptoms of an allergic reaction.
- ↑ Gamlin, Linda (2005). The Allergy Bible. London: Quadrille Limited. p6.
- ↑ White, Dr.T. (1990). Living with Allergies. London: Franklin Watts Ltd.