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. Key words: cutaneous mastocytosis, children, urticaria pigmentosa, c-kit mutation.