Nevus count on specific anatomic sites as a predictor of total body count: a survey of 3,406 children from Italy.

Scanty information is available on the relation between nevus count on specific anatomic areas and the total body surface, particularly in children. The authors analyzed this issue by using data from a uniquely large study conducted in 1997 on 3,406 schoolchildren (1,746 boys and 1,660 girls) aged 13-14 years in 13 cities from northern, central, and southern Italy. Children were examined by trained dermatologists who counted melanocytic nevi (>or=2 mm in diameter) on 19 different anatomic sites. Overall, the mean number of nevi was 17.3 (18.6 in boys and 15.8 in girls). The adjusted correlation coefficients (r) with number of nevi on the whole body were 0.74 for head and neck, 0.83 for anterior and 0.84 for posterior trunk, and 0.88 for upper and 0.80 for lower limbs. With reference to single anatomic sites, the best predictor of total nevus count was the lateral arms (r=0.80), overall and in strata of sex and pigmentary characteristics. This large study provides definite evidence that examining the upper limbs only, particularly the lateral arms, is a practical and suitable tool for predicting total nevus count in children.