What is the mechanism of allergy?
In allergy suffers the immune system produces large amounts of an antibody called Immunoglobulin E (IgE) as part of a confused defense strategy against harmless allergens. Normal individuals do not produce IgE antibody following exposure to allergens. The IgE antibody to the specific allergens enters the blood circulation and distributes to all parts of the body. The IgE antibody has a natural tendency to bind to mast cells present in the skin and mucosal tissues because these cell have special anchoring points for IgE molecule on their surface. Each mast cell may have half-million IgE antibody molecules attached on its surface. Such a person is said to be sensitized to the specific allergen and is ready to react to the allergen on further contact with it. The interaction between the IgE molecules-on-the-mast cell and the allergen causes the mast cell to release powerful chemical mediators (such as histamine, leukotrienes, cytokines and others) that immediately cause inflammation and rash at the site. Thus, two conditions are necessary for allergy to occur: (1) An acute IgE-mediated hypersensitivity to allergens, and (2) Recurrent or continuous exposure to the specific allergen. The absence of either causes the allergy to disappear. In contrast, the taking of medication merely suppresses the symptoms of allergy.

Therefore, the quantities measurement of total IgE levels and allergen-specific IgE antibodies is the key to effective diagnosis and management of allergy.