Clinical Approach to MCAS Diagnosis and Cutaneous Mastocytosis

Authors: Susan Laubach, MD and Kathleen Luskin, MD

Editor: Kathleen Luskin, MD

Introduction 

Mast cell (MC) disorders are conditions characterized by the effects of MC mediators, such as histamine, tryptase, leukotrienes, and prostaglandins, on the skin, gastrointestinal, respiratory, and cardiovascular systems. Mast cell activation syndrome (MCAS) and mastocytosis typically entail widespread mast cell activation, or clonal mast cell proliferation, often affecting multiple organ systems. Mastocytosis is defined by an abnormal clonal expansion of MCs and can be divided into cutaneous mastocytosis (CM), systemic mastocytosis  (SM), and mast cell sarcoma (MCS) [1].