IMMUNOLOGY

Detailed explanation-1: -Anaphylaxis. Anaphylaxis is a medical emergency as it can lead to acute, life-threatening respiratory failure. It is an IgE-mediated process. It is the most severe form of an allergic reaction, where mast cells suddenly release a large amount of histamine and later on leukotrienes.

Detailed explanation-2: -Allergies. An allergy is a disorder in which the immune system makes an inflammatory response to a harmless antigen. It occurs when the immune system is hypersensitive to an antigen in the environment that causes little or no response in most people.

Detailed explanation-3: -When a harmless substance such as dust, mold, or pollen is encountered by a person who is allergic to that substance, the immune system may over react by producing antibodies that “attack” the allergen. The can cause wheezing, itching, runny nose, watery or itchy eyes, and other symptoms.

Detailed explanation-4: -Allergy is often equated with type I hypersensitivity (immediate-type hypersensitivity reactions mediated by IgE), and will be used in this sense here.