MAST CELL ACTIVATION SYNDROME AND ANTI -IMMUNOGLOBULIN E THERAPY FOR THERAPY-RESISTANT MCAS

Abstract

<h3>Introduction</h3> Patients with mast cell activation syndrome (MCAS) may present with a variety of symptoms including flushing, urticaria, GI symptoms and headaches. In about 40% of patients, there is a failure of response to the recommended traditional therapy with anti H1/H2 and leukotriene modulating agents (LMAs) and a definitive effective treatment for MCAS has yet to be established. The aim of the current report is to present a medically challenging patient with therapy-resistant MCAS who responded favorably to omalizumab. <h3>Case Description</h3> A 53-year-old white female was evaluated for recurrent episodes of flushing, dermographism, urticaria, headaches, GI complaints and episodes of syncope, symptoms congruent with a diagnosis of MCAS. Our evaluation revealed elevated tryptase serum concentrations of 21.1 mcg per liter and a negative KIT D816 mutation test assay. Since there was no improvement following an initial course of therapy with anti H1/H2 and LMAs, treatment with omalizumab 300 mg SQ q4 weeks was initiated that led to resolution of her flushing, urticaria, GI symptoms and episodes of syncope. <h3>Discussion</h3> MCAS is a disorder that affects multiple systems including the skin, gastrointestinal, cardiovascular and the respiratory system with a small subgroup of patients who do not respond to traditional therapies. Our patient's favorable response to omalizumab, significantly improving her quality of life, should prompt the performance of larger well-controlled studies evaluating its potential use for patients with MCAS resistant to conventional therapies.