Imatinib and Trigger Avoidance for Mast Cell Activation Syndrome Presenting With Attacks of Abdominal Pain, Nausea, Vomiting, and Diarrhea.

The etiology for concurrent attacks of abdominal pain, nausea, vomiting, and diarrhea can be obscure. Mast cell activation syndrome is not usually considered in this differential diagnosis. A 53-year-old paint salesman suffered severe attacks of these symptoms for the 3 decades of his career. Nortriptyline, loperamide, hyoscyamine, and ondansetron failed to address his symptoms. Mast cell activation syndrome was ultimately diagnosed. Intravenous mast cell-targeted therapy reduced severity of attacks. Multiple oral mast cell-targeted treatments were ineffective, but addition of low-dose imatinib resulted in dramatic improvement. Recognition that paint-fume exposure-triggered attacks led to behavioral modifications which further reduced symptoms.