An allergy is the response of the body's immune system to normally harmless substances

Most people do not have any problem when they come in contact with these substances, only some will suffer from an allergic disease: those whose immune system does produce a specific kind of antibodies, the immunoglobulin E (IgE).
Due to the production of immunoglobulin E, over a variable period of time these subjects sensitise. IgE antibodies bind to the surface of cells in the body called mast cells.

The appearance of allergic symptoms occurs when allergens come in contact with IgE bound to mast cells, which release harmful substances that are responsible for the inflammation and damage of the mucous membranes of affected organs.