Mast Cell Activation Syndrome/Disorders

Definitions, Criteria and Global Classification of Mast Cell Disorders with Special Reference to Mast Cell Activation Syndromes: A Consensus Proposal (2011)

Peter Valenta, Cem Akin, Michel Arock, Knut Brockow, Joseph H. Butterfield,
Melody C. Carter, Mariana Castells, Luis Escribano, Karin Hartmann, Philip Lieberman, Boguslaw Nedoszytko, Alberto Orfeo, Lawrence B. Schwartz, Karl Sotlar
Wolfgang R. Sperr, Massimo Triggiani, Rudolf Valente, Hans-Peter Horny,
Dean D. Metcalfe


Activation of tissue mast cells (MCs) and their abnormal growth and accumulation in various organs are typically found in primary MC disorders also referred to as mastocy- tosis. However, increasing numbers of patients are now be- ing informed that their clinical findings are due to MC activa- tion (MCA) that is neither associated with mastocytosis nor with a defined allergic or inflammatory reaction.

In other patients with MCA, MCs appear to be clonal cells, but criteria for diagnosing mastocytosis are not met. A working confer- ence was organized in 2010 with the aim to define criteria for diagnosing MCA and related disorders, and to propose a global unifying classification of all MC disorders and patho- logic MC reactions. This classification includes three types of ‘MCA syndromes’ (MCASs), namely primary MCAS, second- ary MCAS and idiopathic MCAS.

MCA is now defined by robust and generally applicable criteria, including (1) typical clinical symptoms, (2) a substantial transient increase in se- rum total tryptase level or an increase in other MC-derived mediators, such as histamine or prostaglandin D2, or their urinary metabolites, and (3) a response of clinical symptoms to agents that attenuate the production or activities of MC mediators. These criteria should assist in the identification and diagnosis of patients with MCAS, and in avoiding misdi- agnoses or overinterpretation of clinical symptoms in daily practice. Moreover, the MCAS concept should stimulate re- search in order to identify and exploit new molecular mech- anisms and therapeutic targets. 

Emergency Room Protocol courtesy of The Mastocytosis Society

Navigating emergency rooms with complex conditions can be tricky. This downloadable packet includes an Emergency Response Plan to be signed ahead of time for your Physician, space for your personal health history, allergies, medications, and beyond! 

Mast Cell Activation Disorders

Presentation by Dr. Anne Maitland courtesy of Ehlers Danlos Society


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