Anaphylaxis is a serious and life-threatening allergic reaction. In order to understand anaphylaxis, it is helpful to first understand allergies. In allergic people, the body is overly sensitive to certain substances in the environment.
Many people are sensitive to cat dander, dust, and pollens, for example.
When sensitive people are exposed to these substances, their bodies react by slowly releasing chemicals that can cause itchy eyes and a runny nose, hives or a skin rash, or difficulty breathing. Anaphylaxis occurs when a person is extremely sensitive to a certain substance. Sudden exposure to the substance results in the immediate release of chemicals into the bloodstream. These chemicals cause the sudden beginning of symptoms. Early symptoms of an anaphylactic reaction can include Itching.