Allergies

• An allergy, or hypersensitivity reaction, occurs when the body's immune system overreacts to a substance that is normally harmless (allergen), such as mold, pollen, animal dander or dust mites.The white blood cells of an allergic individual produce an antibody called immunoglobulin E (IgE), which attaches to the allergen. This triggers the release of histamine and other inflammatory chemicals that cause allergic symptoms, such as runny nose, watery eyes and hives.
• If the allergen is airborne, the allergic reaction will primarily affect the eyes, nose and lungs. If the allergen is ingested, the allergic reaction will primarily affect the mouth, stomach and intestines. If enough inflammatory chemicals are released, a reaction such as hives or rash could occur throughout the body. The most severe allergic reaction, known as anaphylaxis, can lead to low blood pressure, breathing difficulties, shock, and loss of consciousness, all of which can be fatal.
• Allergies are extremely common, affecting more than 20% of Americans. The most common allergy triggers include pollen, dust mites, molds, animal dander, latex, foods and insect venom.
• Allergy treatment depends on the type of allergy and severity of symptoms. Commonly used allergy medications include antihistamines, nasal sprays, decongestants, leukotriene inhibitors and allergen immunotherapy (allergy shots).

Related Terms:

• Allergen, allergic, allergic reaction, allergic response, allergy, allergy shots, anaphylactic reaction, anaphylaxis, animal dander, antibodies, antibody, antihistamines, dander, decongestants, dust, dust mites, histamine, hives, hypersensitivity, immune, immune defense system, Ig, IgE, immune-mediated, immune response, immune system, immunoglobulin, immunoglobulin E, immunotherapy, inflammation, latex, molds, leukotriene inhibitors, pet dander, pollen, radioallergosorbent test, RAST, sensitized, sensitization, skin test, trigger, white blood cells.