Mast Cell Activation Syndrome: Tools for Diagnosis and Differential Diagnosis

J Allergy Clin Immunol Pract. 2020 Feb;8(2):498-506. doi: 10.1016/j.jaip.2019.08.022. Epub 2019 Aug 27.


The current consensus diagnostic criteria for mast cell activation syndrome(s) (MCAS[s]) were first established in 2012 and updated in 2019. This diagnosis has been attached to multiple medical conditions not intended as part of the diagnosis. In this article, the diagnostic criteria are reviewed and other diseases in the differential diagnosis outlined. The goal of this review is to provide a tool for evaluation of patients with conditions that can mimic MCAS. Furthermore, the potential role for hereditary alpha-tryptasemia in this group of disorders is discussed.

Keywords: Diagnostic algorithm for MCAS; Diagnostic criteria of MCAS; Differential diagnosis of MCAS; Hereditary alpha-tryptasemia (HAT); Leukotriene E(4); Mast cell activation syndrome (MCAS); Mastocytosis; N-Methylhistamine; Prostaglandin; Tryptase.

Publication types

  • Review

MeSH terms

  • Diagnosis, Differential
  • Humans
  • Mast Cells*
  • Mastocytosis* / diagnosis
  • Motivation