immune disorders
Anaphylactic Reactions
Introduction
Anaphylactic reactions are sudden, widespread, potentially severe and life-threatening allergic reactions. Anaphylactic reactions often begin with a feeling of uneasiness, followed by tingling sensations and dizziness. People then rapidly develop severe symptoms, including generalized itching and hives, swelling, wheezing and difficulty breathing, fainting, and/or other allergy symptoms. These reactions can quickly become life threatening. Avoiding the trigger is the best approach. Anaphylactic reactions require emergency treatment. Affected people should always carry a self-injecting syringe ofepinephrine. (See also Overview of Allergic Reactions .) Like other allergic reactions, an anaphylactic reaction does not usually occur after the first exposure to an allergen (the substance that triggers an allergic reaction) but may occur after a person is exposed to the allergen again. However, many people do not recall a first exposure. Any allergen that causes an anaphylactic reaction in a person is likely to cause that reaction when the person is exposed again, unless measures are taken to prevent it. 