METHODS: Retrospective review of CM patients seen at Texas Children’s Hospital from January 2006 to August 2017. Patients with CM diagnosis and positive Darier’s sign were included.
RESULTS: We identified 114 CM patients. There were 60 males and 54 females. Median age was 4 years (5 months-17 years). One hundred and two (89%) patients were diagnosed with UP, 10 (8.7%) with M and 4 (3.5%) with DCM. According to CM type, UP and M patients had median tryptase level of 5.6 ng/ml (2-19 ng/ml; normal < 10 ng/ml), and values for DCM patients were 18, 75, 160 and 283 ng/ml. Serum tryptase level was between 10-20 ng/mL in seven UP patients. Twelve (10.7%) patients with UP and M had systemic symptoms: pruritus, flushing, diarrhea. Only 3 of these patients with systemic symptoms had elevated tryptase. Bone marrow biopsy performed in one patient was normal. C-kit mutation was positive on skin biopsy in one patient but was not associated with elevated tryptase.
CONCLUSIONS: Serum tryptase levels obtained in this large cohort support the recommendation of limiting investigations for systemic mast cell disease in pediatric CM patients with serum tryptase < 20 ng/mL.