Symptoms and signs of anaphylaxis 26Treatment of anaphylaxis 28Prevention of anaphylaxis 31Anaphylaxis is defined as an immediate systems hypersensitivity event produced by IgE-mediated release of chemicals from mast cells and basophils. Theoretically, prior exposure to the agent is required and the reaction is not dose- or route-related, but in practice anaphylaxis to injected antigen is more frequent, severe, and rapid in onset than following exposure to oral or topical antigen....