Abstract
Mast Cell Activation syndrome (MCAS) is a clinical condition, defined by the combination of 1) typical symptoms, 2) laboratory abnormalities and 3) response to treatment. Patients present with episodic symptoms of aberrant mast cell activation, such as abdominal cramping, asthma, hypotensive episodes, tachycardia, anaphylaxis, unexplained arrhythmias, and neurologic/psychiatric symptoms. Both clonal and nonclonal mast cell activation syndromes have been described, with a greater prevalence of non-clonal MCAS among the pediatric and adult population. Numerous extrinsic triggers of mast cell activation (MCA) are described, but recent reports point to nonatopic triggers, as the predominant, extrinsic stimulants of MCA in the adult population. The etiology of MCAS is unclear, though recent studies point to the disruption of the epithelium by infection, toxic exposures or physical trauma, and perturbation the tight regulation of these innate immune cells, associated to the epithelial borders. Here we describe a geriatric patient with adult onset MCAS, following a significant toxic exposure, scombroid poisoning. We also review the relevant literature regarding MCAS diagnosis and management as well as potential mechanisms for this hypersensitivity syndrome in adults.