Anaphylaxis definition, overview, and clinical support tool: 2024 consensus report—a GA2LEN project

Background: The 2006 National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network anaphylaxis criteria are widely used in clinical care and research. In 2020, the World Allergy Organization published modified criteria that have not been uniformly adopted. Different criteria contribute to inconsistent care and research outcomes. Objective: We sought to develop a consensus anaphylaxis definition, overview, and clinical support tool. Methods: A 12-member writing group developed draft outputs modified with input from a 46-member international expert panel, 31 medical stakeholder organizations, and 15 patient advocacy organizations. The expert panel participated in a modified Delphi process to seek consensus for the outputs using a ≥80% consensus threshold. Results: The first sentence of the definition reads, “Anaphylaxis is a serious allergic (hypersensitivity) reaction that can progress rapidly and may cause death.” The definition also describes organ systems that may be involved and signs of life-threatening reactions. The overview includes details of anaphylaxis recognition and management. The clinical support tool incorporates new clinical criteria to help determine the likelihood that patients are having anaphylaxis, intramuscular epinephrine indications and dosing, and common findings from the anaphylaxis organ systems. In addition, 93.5% (43/46), 97.8% (45/46), and 93.5% (43/46) of experts agreed with the definition, overview, and clinical support tool, respectively. Conclusion: The anaphylaxis overview is a novel educational tool conveying key elements of anaphylaxis recognition and management. We propose that the definition and clinical support tool should replace previous definitions and clinical criteria. The clinical support tool should facilitate improved anaphylaxis recognition and management across different clinical settings and standardize research outcomes.