a substance that causes an allergic reaction triggers the release of a class of substances known as
Allergy Common allergens include pollen and certain food.[10] Metals and other substances may also cause problems.[10] Food, insect stings, and medications are common causes of severe reactions.[3] Their development is due to both genetic and environmental factors.[3] The underlying mechanism involves immunoglobulin E antibodies (IgE), part of the body's immune system, binding to an allergen and then to a receptor on mast cells or basophils where it triggers the release of inflammatory chemicals such as histamine.[11] Diagnosis is typically based on a person's medical history.[4] Further testing of the skin or blood may be useful in certain cases.[4] Positive tests, however, may not mean there is a significant allergy to the substance in question.[12]