ANAPHYLAXIS AND INSECT ALLERGY: Edited by Gianenrico Senna and Mariana CastellsMast cell activation syndrome: is anaphylaxis part of the phenotype? A systematic reviewSabato, Vitoa,b; Michel, Moïsec,d,e; Blank, Ulrichf; Ebo, Didier G.a,b; Vitte, Joanad,e,g Author Information aUniversity of Antwerp, Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence bAZ Jan Palfijn Gent, Department of Immunology and Allergology, Ghent, Belgium cLaboratoire d’Immunologie, CHU de Nîmes, Nîmes dAix-Marseille Univ, IRD, APHM, MEPHI eIHU Méditerranée Infection, Marseille fUniversité de Paris, Centre de Recherche sur l’Inflammation, INSERM UMR1149, CNRS ERL8252, Faculté de Médecine site Bichat, Paris, France; Laboratoire d’Excellence Inflamex, Paris, France gIDESP, INSERM UMR UA 11, Montpellier, France Correspondence to Vito Sabato, MD, PhD, University of Antwerp, Faculty of Medicine and Health Sciences, Immunology – Allergology – Rheumatology, Campus Drie Eiken T5.95, Universiteitsplein 1, 2610 Antwerpen, Belgium. Tel: +32 (0) 3 2652595; e-mail: [email protected] Current Opinion in Allergy and Clinical Immunology: October 2021 - Volume 21 - Issue 5 - p 426-434 doi: 10.1097/ACI.0000000000000768 Buy Metrics Abstract Purpose of review Mast cell activation syndrome (MCAS) and anaphylaxis are the result of a spontaneous or triggered pathological degranulation of mast cells (MCs) and might have as substrate normal or pathological MCs (increased burden, aberrant MCs or both). Recent findings This review summarizes the most recent evidence on immunoglobulin E (IgE)-mediated and non IgE-mediated mechanisms underlying MC activation and degranulation and highlights the importance of standardized diagnostic criteria for MCAS. Application of these criteria implies that in most cases the clinical presentation of MCAS meets the diagnostic criteria for anaphylaxis. Summary Integrating clinical parameters and diagnostic test recognition and underlying clonal MC disease are of utmost importance for a patient-tailored approach. Hereditary alpha-tryptasemia can be encountered in context of anaphylaxis, MCAS and primary MC disorders. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.