An Allergy is a hypersensitivity to foreign substances which are normally
harmless but which produce a violent reaction in the allergy sufferer. Allergies are generally the body's effort to eliminate something it considers unsuitable. Typical allergic reactions are
hay fever, migraine,
hyperactivity in children,
recurrent sinusitis and
In a few people the histamine (anaphylactic) reaction can cause muscle
cramps, disorientation, unconsciousness and death from shock
There are different types of Allergies, the most common being type1.
When an allergen encounters cells capable of antibody formation, they
then form IgE antibodies which bind to the surface of other cells, called
mast cells and basophils. In response to the attachment those cells release
chemicals, called mediators of anaphylaxis, among them histamine.
Those chemicals cause allergic reactions such as swelling or the secretion
Almost any substance can be an allergen for an individual. Common
allergens include certain foods, especially milk, wheat and eggs, pollens,
dust, moulds, cosmetica and certain
An Allergy is not the same as an intolerance. Allergies always involve the
immune system, whereas an intolerance, eg. lactose intolerance, is caused
by a lack of lactase, the enzyme that converts lactose into glucose.