Mast Cell Activation Syndromes

Abstract

Mast cell activation syndromes(MCAS) are disorders associated with mast cell activation (MCA), and include Primary MCAS, Secondary MCAS and Idiopathic MCAS. MCAS are characterized by clinical symptoms of MCA in cutaneous, gastrointestinal, respiratory, cardiovascular, musculoskeletal and neurological organs. Mast cell (MC) mediators such as tryptase in serum, and/or histamine or prostaglandin urinary metabolites are typically elevated at base line or transiently during episodes of MCA, and there is a total or partial response to mast cell mediators controller medications. In primary MCAS an activating point mutation at codon 816 of KIT on MC is present in most cases of Systemic Mastocytosis (SM) and Monoclonal Mast Cell Activation Syndrome (MMCAS) and is absent in secondary and Idiopathic MCAS. MCAS might be the underlying cause of unexplained symptoms when several organ systems are involved, such as the gastrointestinal tract and the skin. It is especially important to be able to recognize the constellation of clinical features because response to anti-MC mediator medications is often excellent. This update on mast cell disorders (MCD) provides an insight into the classification, clinical presentations, diagnosis, treatment and management. We describe associated conditions, such as Hymenoptera Reactions, Familial Tryptasemia, Postural Orthostatic Tachycardia Syndrome and Ehlers-Danlos Syndrome.