Cutaneous mastocytosis in children: a clinical analysis of 71 cases.

OBJECTIVE: To characterize the clinical features, response to therapy, evolution and prognosis of cutaneous mastocytosis in children.

BACKGROUND: Mastocytosis in children, instead of being induced by a potentially oncogenic c-kit mutation, is probably a clonal disease with benign prognosis.

METHODS: The clinicopathological features, evolution and response to treatment were analysed in 71 children with mastocytosis.

RESULTS: There were 53 (75%) cases of urticaria pigmentosa, 12 (17%) cases of mastocytoma, and six (8%) cases of diffuse cutaneous mastocytosis. In 92% of cases disease onset was in the first year of life. There was a male predominance 1.8 : 1. Treatment did not modify the disease evolution. Eighty per cent of patients improved or had spontaneous resolution of the disease.

CONCLUSION: The most frequent clinical form of mastocytosis was urticaria pigmentosa followed by mastocytoma and diffuse cutaneous mastocytosis. Darier's sign was present in 94% of cases. A negative Darier's sign does not rule out mastocytosis. In contrast to adults, mastocytosis in children usually has a benign course making sophisticated or invasive diagnostic tests unnecessary. A classification of paediatric cutaneous mastocytosis is proposed.