Background: Melanocytic nevus is the strongest risk factor for the development of cutaneous melanoma. Fair skin and exposure to UV light, especially in childhood, are correlated with the development of childhood nevi.
Objective: To assess the role of blue light neonatal phototherapy used to treat hyperbilirubinemia in nevus acquisition in childhood.
Design: Case-control prospective study.
Setting: University hospital.
Participants: Fifty-eight children were included in this study. Selection criteria included the following: age, 8 to 9 years; and skin type, less than IV by Fitzpatrick classification (ie, brown, always tans, rarely burns). The case group consisted of 18 children exposed to neonatal phototherapy (mostly intensive phototherapy) retrospectively found by review of consecutive neonatal medical records at Saint-Antoine Hospital, Paris, France. The control group was composed of 40 nonexposed children consecutively recruited from a public school in the same geographic area.
Main outcome measures: Total body nevus count in children, phenotypic characteristics, solar exposure, and demographic data were assessed by the same dermatologist.
Results: A comparison of both groups showed that the number of nevi larger than 2 mm was significantly higher in the exposed group. The mean (SD) nevus count was 3.5 (3.05; median, 3.0) per child in the exposed group, compared with 1.45 (1.99; median, 1.0) per child in the nonexposed group (P(mean) = .02 and P(median) = .01). Multivariate analysis confirmed these results, with a statistically significant correlation with nevus count, especially with nevi 2 to 5 mm in greatest diameter. The association between neonatal phototherapy and nevus count was not significant for nevi smaller than 2 mm or larger than 5 mm. Solar exposure, especially during vacations, was strongly associated with total nevus count and all nevus sizes (2-5 mm, <2 mm, and >5 mm). At univariate analysis, hair color was significantly associated with nevus size smaller than 2 mm (P(mean) = .03).
Conclusions: Intensive neonatal phototherapy is a strong risk factor for nevus development in childhood. While childhood development of nevi is correlated with fair skin and solar light exposure, and having many nevi is a recognized risk factor in persons with melanoma, we must be careful not to equate childhood nevi development in response to neonatal phototherapy with an individual's risk of developing melanoma. The treatment of hyperbilirubinemia remains neonatal phototherapy. Exposed children should undergo dermatologic preventive measures and surveillance for the development of melanoma.