Anaphylaxis: managing and preventing a true emergency.

Anaphylaxis is the sudden, life-threatening reaction to an antigen. It generally results from the injection of a potent antigen. However, it may be caused by the inhalation or ingestion of any antigen or allergen as well. Although anaphylaxis may occur after a single exposure to an antigen, it usually occurs after repeated exposures. There is general agreement that the sooner it occurs after exposure to the antigen, the more likely it is that the reaction will be severe. The focus of this article will be on the management and prevention of immediate hypersensitivity (anaphylaxis) induced by immunoglobulin E(IgE) or type I. Since anaphylaxis is often iatrogenic, every practitioner has a responsibility to prevent this hypersensitive state from occurring. When it does happen, prompt recognition and treatment can be lifesaving. Management needs to be initiated quickly whenever anaphylaxis seems imminent.