ANATOMY

Detailed explanation-1: -Allergies occur when your immune system reacts to a foreign substance-such as pollen, bee venom or pet dander-or a food that doesn’t cause a reaction in most people.

Detailed explanation-2: -Hypersensitivity reactions are exaggerated or inappropriate immunologic responses occurring in response to an antigen or allergen. Type I, II and III hypersensitivity reactions are known as immediate hypersensitivity reactions because they occur within 24 hours of exposure to the antigen or allergen.

Detailed explanation-3: -Allergies are the result of your immune system’s response to a substance. Immune responses can be mild, from coughing and a runny nose, to a life-threatening reaction know as anaphylaxis. A person becomes allergic when their body develops antigens against a substance.

Detailed explanation-4: -Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you’re allergic to, such as peanuts or bee stings.

Detailed explanation-5: -Allergy is often equated with type I hypersensitivity (immediate-type hypersensitivity reactions mediated by IgE), and will be used in this sense here.