A new study published in the European Journal of Pediatrics suggests that low bone mineral density may not be a major concern for most children with mastocytosisMastocytosis Rare disease caused by the buildup of mast cells. Cutaneous mastocytosis primarily affects the skin and is more common in children, while systemic mastocytosis affects internal organs and is more common in adults., offering reassurance for families and clinicians who have long relied on adult data to guide care.
In adults, mastocytosis has been strongly linked to osteoporosis and fractures, but until now little research had examined bone health in children with the condition. To address this gap, researchers conducted what they describe as one of the first studies focused specifically on bone mineral density in pediatric mastocytosis.
The study’s authors collected clinical and laboratory information, including mastocytosis subtype, serum tryptaseTryptase A protein enzyme that is primarily produced by mast cells and stored in small pockets within the cells, known as granules. High levels of tryptase are a key indicator of SM. levels and genetic mutation status, from a database at a children’s hospital in the Netherlands spanning from 2004 to 2025. Bone mineral density was measured using dual-energy X-ray absorptiometry (DEXA) scans of the lumbar spine and total body in children aged 4 to 18 years.
The study included 76 children, the majority of which (73) had cutaneous mastocytosis, while three were diagnosed with indolent systemic mastocytosis (SM). Low bone mineral density, defined as a Z-score of −2 or lower, was detected in 6.8% of children with cutaneous mastocytosis. Although this rate was higher than in the general pediatric population, all affected children experienced spontaneous normalization of bone density during follow-up.
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The children with indolent SMIndolent SM A subtype of nonadvanced SM caused by the abnormal accumulation of mast cells in the bone marrow and other organs. Indolent SM accounts for around 90% of SM cases. had higher serum tryptase levels, a marker of mast cellMast cell A type of white blood cell produced in the bone marrow. They help defend against infections and play a key role in allergic reactions. In SM, mast cells become overactive and build up throughout the body. burden, but their bone mineral density remained normal.
None of the study participants developed osteoporosis. Bone mineral density also showed no relationship with disease characteristics, bone pain or fractures, suggesting that reduced bone density did not translate into clinically significant bone complications in this population.
While the study is limited in its small sample size, the researchers say the findings suggest that routine bone density screening may not be necessary for every child with mastocytosis. Instead, they suggest that DEXA scans could potentially be reserved for children with suspected systemic involvement.
“Future research should focus on BMD in a larger, more representative pediatric mastocytosis cohort, preferably with longitudinal follow-up of bone density to further elucidate bone involvement in pediatric mastocytosis,” the study’s authors concluded.
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