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ABC's Of Allergies
(Released August 2006)

  by Sujata Suri  


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Allergy is one of the most widespread diseases of the modern world. More than 25% of the population in industrialized countries suffers from allergies (Valenta; 2002). According to the Asthma and Allergic Foundation of America (2002), allergies are the sixth leading cause of chronic diseases in the U.S, and the annual cost of dealing with them is estimated at $18 Billion.

grass in a meadow
Grass shedding pollen, a common allergy source

Every individual has his or her own immune system; the stronger the immune system, the healthier will be the person. Allergies, also known as hypersensitive reactions, occur when the immune system overreacts to substances that do not affect most people. These substances, also known as allergens, could be pollen, animal dander, chemicals, fungi, dust mites, or foods such as nuts, eggs, shellfish, fish, and milk.

extreme close-up of dust mite
The house dust mite and its droppings are common allergens
Different people show different symptoms of allergies, which can be mild (runny nose) to severe (anaphylaxis). Symptoms generally depend upon the part of body contacted by the allergen, e.g., pollens from the air enter the respiratory tract via the nose and cause respiratory symptoms such as cough, itchy and runny nose, nasal congestion, sneezing, and wheezing. Food allergy related symptoms include vomiting, nausea, abdominal pain, and diarrhea. Skin allergy symptoms are lesions, rashes, blisters, redness and itchiness, and so on.

Go To The Immunology of Allergies

Special thanks to Deborah Whitman for her invaluable help with this Discovery Guide

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