Definition and criteria for the diagnoses of anaphylaxis

Abstract

It seems anti-intuitive that a phenomenon such as anaphylaxis, with explosive-manifestations and distinct symptoms, should be difficult to define. However, since its discovery as a medical event in humans, there have been numerous different definitions. These definitions have evolved over approximately one century since the first demonstration of an anaphylactic event in an animal model. Although we clearly understand the mechanism of production of anaphylactic events, and a successful treatment paradigm has been discovered, there is still debate as to the proper definition of the term anaphylaxis. This debate has revolved around the different mechanisms of production, specifically whether the event in question is mediated by IgE, other immunologic mechanisms, or is non-immunologic. The discussion has also revolved around the clinical manifestations required to clearly establish the presence of an anaphylactic event, versus, for example, an immediate hypersensitivity disorder not reaching the requirements for an anaphylactic episode. Thus, a number of meetings have been called and a number of physician statements have been published over the years in an attempt to refine the definition of anaphylaxis and to gather a consensus as to all it includes. This chapter traces the history of the various definitions of this condition, and focuses on those that have more recently appeared in the literature. It also briefly discusses the mechanism of production of these events and their clinical manifestations that have prompted the various definitions in question. © 2011 Springer Science+Business Media, LLC.