Tuesday, November 6, 2007

Definition of Allergies

Allergies are abnormal reactions to ordinarily harmless substances. Awareness of substances called allergens, can be inhaled, swallowed or come into contact with skin. Allergens causing problems most frequently are: pollen, mold spores, dust mites, animal danders, food, insect bites or stings, plants, insects, spores, latex, viruses , bacteria, drugs and environmental conditions (such as cold temperatures). Allergic reactions can occur in a specific area, such as sneezing or a rash or sneezing, or may include more than one symptom. Description of Allergies Normally, the body learns to defend itself through experience by the encounter, battling and remembering one enemy after another. For decades, medical science has taken advantage of this capability through the use of vaccination to create immunity of the immunological "memory" of a disease. Allergic reactions occur after the immune system learns to recognize wrongly innocent foreign substances (allergens) as potentially harmful. The following story illustrates how can develop an allergy: More than a field of ragweed plants floats invisible cloud of pollen grains, quickly swept away by the wind in a nearby city. The pollen is inhaled by a child, whose body has never been exposed to this substance before. Due to some factors of genetic predisposition, this child's immune system and produces an excessively large number of IgE antibodies, all specially designed to respond to ragweed pollen. Several antibodies attach themselves to cells in the child nasal passages and upper respiratory tract. These cells (known as mast cells) contain strong chemicals called mediators, the best known of which is histamine. Later, when the child inspires the same type of pollen, the proteins bind pollen in a lock and key fashion specially designed antibodies on the surface of mast cells. That triggered an explosion of sorts, as mediators burst from inside the mast cells, destroying the pollen and also damage surrounding tissue. The results are sneezing, a stuffy head, sniffling, stuffed-up head and red, watery eyes, a well-known stamps allergies. Causes and Risk Factors of Allergies The fundamental cause of allergy is not yet known. The problem tends to be hereditary. An individual is allergic more likely to have parents who are allergic to be on the basis of chance, but not hereditary factors appear to play a role as well. The proof is the fact that children who are breastfed are less likely to develop allergies than bottle-fed babies. The reason why a person is sensitive to certain substances and not to others remains a mystery. Individuals may be affected by a variety of allergic diseases. The most common allergic diseases are allergic rhinitis, non-allergic rhinitis, asthma, allergic dermatitis, contact dermatitis and urticaria. (Allergic rhinitis is the most common allergic diseases and the main purpose of this profile health. More comprehensive information about other conditions can be found under that term.) Allergic rhinitis is a general term used to ask all those who have an allergy based on symptoms. Allergic rhinitis can be a seasonal problem (commonly known as "hay fever" or pollen allergy) or all year (commonly known as perennial allergic rhinitis). Hay fever, or seasonal allergic rhinitis is caused by an allergy to pollen from trees, grasses, weeds or mold spores. Perennial allergic rhinitis is caused by house dust, animal danders, molds and certain foods. Asthma is caused by intrinsic and extrinsic factors (inhalation). Intrinsic factors are pollen, dust, mites, animal fur, feathers or animal hair. Extrinsic factors are respiratory infections; A cough, cold or bronchitis; The exercise, and tobacco smoke or other air pollutants, which can be caused by an allergy to a particular food or medication. Eczema, also known as allergic dermatitis, or atopic dermatitis, can be caused by food or other allergens. Contact dermatitis is caused by exposure to certain plants (such as poison ivy or poison oak), cosmetics, pharmaceuticals, metals and chemicals. Urticaria, also known as "The Hive" is caused by an allergy to foods such as nuts, tomatoes, shellfish and berries. Hives can also be caused by drugs, such as aspirin and penicillin.

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