The word allergy has been first used by an Austrian pediatrician, Clemens Pirquet. The word is derived from Greek words: “allos” (different or changed) and “ergos” (work or action). We may define allergy as an exaggerated or altered reaction of our immune system in response to a contact with certain foreign substances. It is exaggerated because to non-allergic people they are absolutely harmless and inoffensive.
But why some of us have allergic reactions? And why some of us have fatal allergic reactions? The substances that cause allergy are called “allergens”. Allergens may be everywhere: in the air we inspire, clothes, food, medicines, cosmetics… They are recognized by our immune system as a harm or attack. When it happens our organism starts producing defenses: antibodies (proteins called immunoglobulins, specifically gamma E globulins or IgE, for allergic reactions - that are produced to neutralize “the enemy”), histamine.
Than the “attacked” organism, may have some reactions, accordingly to the allergens identified: running nose, sneezing, itching ears and skin, itching eyes, cutaneous rash, hives (urticaria), coughing, fever, chest tightness, tingling sensations of the tongue, swelling of the throat, anaphylactic shock, death. Someone may suddenly become allergic to some food or a medicine that has been having for years. There are genetic and individual characteristics that may explain the allergic reactions, but no one can preview them.
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