Recognition, treatment, and prevention of anaphylaxis.

Anaphylaxis is an acute and potentially lethal multisystem allergic reaction that occurs in a variety of clinical scenarios and is almost unavoidable. Immunologic reactions to medications, foods, and insect stings cause most episodes, but virtually any substance capable of inducing systemic degranulation of mast cells and basophils can produce anaphylaxis. All health care professionals must be able to recognize anaphylaxis promptly, be prepared to treat it appropriately, and be able to provide preventive recommendations. Similarly, at-risk individuals must be prepared to self-treat anaphylaxis promptly if prevention fails.