Clinical Characteristics of Patients in Allergy Clinic with Presumed Diagnosis of Mast Cell Activation Syndrome (MCAS)
Saturday, March 3, 2018
South Hall A2 (Convention Center)
Kristine K Arndt, MD, Ravi K. Viswanathan, MD, Sameer K Mathur, MD PhD FAAAAI
RATIONALE: Mast Cell Activation Syndrome (MCAS) is a newly recognized disorder that has yet to be fully understood. The aim of our study was to characterize patients presenting to clinic for evaluation and treatment of this disorder.

METHODS: Electronic medical record data from patients with mast cell disorder related ICD-10 codes (Q82.2, D89.40, and C96.2) were used to identify 56 patients that had been seen at the University of Wisconsin Allergy Clinic. Five patients with systemic mastocytosis were excluded. All allergy encounters of the remaining 51 charts were reviewed, extracting the following data: demographics, clinical features, medication history with responses, and laboratory findings including serum tryptase and urinary metabolites of histamine, leukotrienes and prostaglandins.

RESULTS: Almost all of the patients were female (94%) with an average age of 45. The most common medical co-morbidities included allergic disease (67%), hypothyroidism (31%), depression (31%), Ehlers-Danlos Syndrome (24%), POTS (24%), anxiety (24%) and GERD (24%). All of the patients presented with a skin complaint, and 90% of patients reported gastrointestinal symptoms. Foods (59%), medications (51%) and stress/anxiety (43%) were the most common reported triggers, causing more than half of patients to alter their diet. Either serum tryptase or a urinary biomarker was positive in the majority of patients (67%), although there was significant variation in which biomarker was elevated.

CONCLUSIONS: MCAS is a majority female disorder that presents with predominately skin and gastrointestinal symptoms. A positive biomarker was present in two thirds of the patients with presumed MCAS.