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.
A 72-year-old female was diagnosed with c-kit-positive ISM. She had no cutaneous manifestations of mastocytosis. Her initial presentation was that of Hymenoptera anaphylaxis, with flushing, palpitations, and loss of consciousness (). She was treated with cetirizine and ranitidine but continued to experience occasional facial flushing, vomiting, lightheadedness, drenching night sweats, and bone pain. Given her history of venom anaphylaxis, omalizumab was started at 300 mg every 4 weeks () for 14 months followed by rush venom desensitization [, ]. Symptoms of her underlying ISM resolved completely on ongoing omalizumab therapy. Tryptase had also fallen from 40.5 to 36.8 ng/ml.