ABSTRACT

Systemic allergic reactions (SARs), including anaphylaxis, are caused by insect venom, foods, medications, allergen immunotherapy, radiocontrast media, and other agents. This chapter defines anaphylaxis along a spectrum of SARs and examines the historical context for terminology used to describe SARs. Allergen immunotherapy causes anaphylaxis in some subjects, a topic of interest to clinicians who prescribe such therapies. Mechanisms of anaphylaxis are outlined including mediators, effector cells, and effects on the cardiovascular system. Manifestations and differential diagnosis of anaphylaxis are discussed. Early recognition and treatment of SARs is emphasized, to prevent progression to a level of severity termed anaphylaxis. Variations on the theme including exercise-induced anaphylaxis, cholinergic urticaria, idiopathic anaphylaxis, and anaphylaxis attributed to endogenous progesterone are explored. Prevention and management of anaphylaxis are addressed.