Body-site distribution of melanocytic nevi in young Australian children.

OBJECTIVE To investigate the body-site distribution of melanocytic nevi (MN) with respect to habitually and intermittently sun-exposed surfaces. DESIGN Cross-sectional survey of MN prevalence. SETTING Townsville (19.16 degrees S), Queensland, Australia. PARTICIPANTS Random sample of 506 1- to 6-year-old white children who were born and raised in Townsville (response, 87.6%). MAIN OUTCOME MEASURES Site-specific counts and densities (number per square meter) of MN. RESULTS Densities of MN of all sizes were highest on the outer forearms, followed by the outer upper arms, neck, and face. The feet had the lowest density of MN. Densities of MN of 2 mm or greater were highest on the upper arms and trunk. Boys had higher densities of MN of all sizes on the neck than girls (P = .002). Girls had higher densities of MN of 2 mm or greater on the lower legs (P = .006) and thighs (P = .005) than boys. Habitually sun-exposed body sites had higher densities, particularly of small MN, than relatively sun-protected sites, and larger MN were most prevalent on the intermittently exposed skin of the trunk. CONCLUSIONS These children have higher total body and site-specific MN counts and densities than children from elsewhere, and their MN are distributed over the body in a way that implicates exposure to sunlight. As sun exposure in childhood and MN are risk factors for melanoma, intervention studies are required to determine if MN can be prevented.