A 49-year-old woman was diagnosed with c-kit-positive ISM with tryptase 11.4 ng/ml (). Symptoms of SM included daily headaches, sporadic flushing, itchy throat, mild coughing, loose stools, lightheadedness, and palpitations. No cutaneous manifestations of mastocytosis were observed. She was markedly intolerant to exercise, heat, and strong emotion, all of which triggered the symptoms in spite of medications, which included ranitidine, loratadine, cetirizine, ketotifen, and montelukast. In early 2017, she experienced 5 anaphylactic reactions, requiring emergency department visits and treatment with epinephrine as well as 5 milder reactions managed at home (). Omalizumab was started at 300 mg at 4-week intervals (). On omalizumab, multisystem reactions were entirely suppressed, with only breakthrough flushing once per week, loose stools roughly twice per month, and occasional lightheadedness. A follow-up one year later revealed complete resolution of symptoms with no adverse reactions to her medications and reduced tryptase to 8.3 ng/ml ().
A 40-year-old female with c-kit-positive ISM had daily flushing, nausea, abdominal discomfort, and loose stools 3-4 times per day. She had cutaneous lesions of telangiectasia macularis eruptiva perstans and tryptase 55.2 ng/ml (). She complained of debilitating bone pain, episodic presyncope, shortness of breath, and frequent palpitations. Ongoing medications included cetirizine, ranitidine, ketotifen, and cromolyn. Treatment with omalizumab 300 mg every 4 weeks was started (). After 3 injections, bone pain and GI symptoms had subsided. After 6 cycles of omalizumab, cutaneous lesions had decreased in number, daily palpitations and syncopal episodes had subsided, and tryptase had increased to 61.7 ng/ml (). She was subsequently able to discontinue both ketotifen and cromolyn with ongoing treatment with omalizumab.