AAAAI Mast Cell Disorders Committee Work Group Report: Mast cell activation syndrome (MCAS) diagnosis and management

J Allergy Clin Immunol. 2019 Oct;144(4):883-896. doi: 10.1016/j.jaci.2019.08.023. Epub 2019 Aug 30.


Our current recommendations for diagnosing and treating primary mast cell (MC) activation syndrome make use of the latest studies and consensus guidelines for clinically recognizing systemic anaphylaxis in real time, regardless of whether allergen-triggered or other pathways are involved; our current understanding of the biomarkers secreted by activated MCs that best discriminate this disorder from other conditions; and the therapeutic drugs that might selectively affect those mediators or MCs themselves. Finding familial or somatic mutations of genes that cause MCs to be hyperactivatable would extend our diagnostic tools and potentially indicate new therapeutic interventions, targeting either the mutated gene product or the associated molecular pathway. In conclusion, we trust that the clinical, laboratory, and therapeutic criteria for primary MC activation syndromes described herein will provide clinicians with practical criteria of sufficient sensitivity and specificity to diagnose most cases without overdiagnosing the disorder in patients who likely have other conditions.

Keywords: Mast cell activation syndrome; anaphylaxis; c-kit; hereditary α-tryptasemia; histamine; leukotriene C(4); mastocytosis; prostaglandin D(2); tryptase.

Publication types

  • Practice Guideline
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Mastocytosis / diagnosis*
  • Mastocytosis / therapy*