Observational studies consistently show that melanocytic nevus prevalence increases with age and that phenotypic traits are significantly associated with nevus count in children. An observational study of 1512 children and adolescents from 2010 to 2013 was conducted. Study dermatologists counted the full body, arm, and facial nevi of each participant. Children and their parents were asked to complete a survey to gather data on personal characteristics, pubertal development and early-life sun exposure. The main aim of the study was to establish pediatric nevus prevalence and its relationship to age, phenotype, sex, menarche, early-life sun exposure, and sun-protection behaviors. Females had a significantly lower nevus count compared to males, but this sex-related difference was significantly modified by menarche. Sun exposure and sun protection habits were all significantly associated with nevus count; in particular, children who used sunscreen with a SPF>30 had a lower nevus count compared to SPF<=30 sunscreen users. The present study shows that sex, menarche status and sun-protection practices significantly influence nevus count in pediatric population.
De Giorgi V, Gori A, Greco A, Savarese I, Alfaioli B, Grazzini M, Rossari S, Papi F, Scarfì F, Janowska A, D'Errico A, Salvati L, Covarelli P, Gandini S.
J Invest Dermatol. 2018 Mar 31. pii: S0022-202X(18)31861-X. doi: 10.1016/j.jid.2018.02.046. [Epub ahead of print].