ALLERGIES: HISTAMINE
AllergiesHistamine is a chemical that is released by the white blood cells (basophils), the blood platelets and the mast cells in that area of the body that a foreign substance is residing. Histamine’s job is to dilate the blood vessels so that extra lymphocytes can arrive quickly on the scene, and speed up the metabolic rate of all the cells in the area, that they may have the energy to protect themselves from and, in the case of lymphocytes, defeat the foreign body (virus, bacteria, fungus, etc.). In this way histamine acts as a normal part of the immune reaction and is vital if we are to survive invasion by infectious agents. Normal amounts of histamine dilate the blood vessels only as much as is needed to supply the required number of lymphocytes to do the job. The arrival of the extra lymphocytes, the dilation of the blood vessels and the increased metabolic rate of the cells in the area, produces only a mild inflammation which, for the main part, goes unnoticed.
If too much histamine is released there is an excessive inflammatory reaction that leads to tissue damage. In these circumstances the immune mechanisms are protecting us at the cost of tissue damage and excessive inflammation (swelling, redness, pain).
Allergic reactions take place in those people whose immune systems habitually over-react to certain antigens. Any antigen that causes such an over-reaction of the immune system is known as an allergen. However individual and different allergic people may be, they all have one thing in common: an immune system that over-reacts to antigens/allergens, such as foods, grasses, pollens, moulds, dust mites, dust, that are normally not life threatening.
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