[Acquired melanocytic nevus. Epidemiologic clinical study of a healthy population].

Total body naevi counts have been performed on 3931 Italian subjects aged 5 to 79 years (2063 males and 1868 females). Only naevi greater than or equal to 2 mm in diameter were recorded. The total mean naevi count was 15 (15 for males, 14 for females); in the first decade of life the count was 8, rising rapidly in the second decade to a mean of 18 and was 22 in the third decade. Thereafter the frequency of naevi declined with age; in the eight decade the number was similar to that seen in children. The association between total naevi count and place of birth of subjects or their parents was not significant. The frequency of naevi varied according to body site: the most common site was the trunk (6 naevi), the next most affected site was the upper arm (4 naevi). Distribution by eye colour, hair colour and number of naevi showed an increase in subjects with blue or green eyes and red or fair hair. High associations were found between large numbers of acquired melanocytic naevi and pale skin. Skin types 1 and 2 had a higher melanocytic naevi count than skin types 3 and 4.