Do Corticosteroids Prevent Biphasic Anaphylaxis?

Anaphylaxis is a severe hypersensitivity reaction that is rapid in onset and can result in death. The pattern of an anaphylactic reaction can be uniphasic (or monophasic), biphasic (also called delayed or late phase), or refractory in nature. The most widely cited definition of biphasic anaphylaxis is a recurrence of anaphylactic symptoms after initial resolution despite no further exposure to the trigger. Corticosteroids are thought by some to prevent the development of biphasic symptoms and, therefore, commonly used in the emergency treatment of anaphylaxis but this has not been systemtically analyzed. In this review, Ovid MEDLINE, Ovid EMBASE, Web of Science, and Scopus were searched for articles using "anaphylaxis" combined with the key terms "biphasic" and/or "corticosteroids" and/or "epinephrine." A total of 31 appropriate studies were identified. Biphasic anaphylactic reactions are more likely to occur in moderate to severe anaphylaxis or when anaphylaxis is not treated with timely epinephrine. Because of the potential detrimental adverse effects of corticosteroids and lack of compelling evidence demonstrating an effective role in reducing anaphylaxis severity or preventing biphasic anaphylaxis, we do not advocate for their routine use in anaphylaxis.