Children who received light therapy (phototherapy) for jaundice as infants appear to have an increased risk of developing skin moles in childhood, according to a report in the December issue of Archives of Dermatology, one of the JAMA/Archives journals. Some types of moles are risk factors for developing the skin cancer melanoma.
Jaundice or hyperbilirubinemia occurs when bilirubin, a yellow pigment created as a byproduct of the normal breakdown of red blood cells, cannot yet be processed by a newborn’s liver and builds up in the blood, turning the skin, whites of the eyes and mucous membranes yellow. The condition affects between 45 percent and 60 percent of healthy babies and as many as 80 percent of infants born prematurely, according to background information in the article. During phototherapy, the treatment of choice for jaundice, babies are placed under blue lights (bili lights) that convert the bilirubin into compounds that can be eliminated from the body. Studies have been performed to assess the safety of this therapy, but many have not focused on its effects on the skin, the authors write.
Emmanuelle Matichard, M.D., Bichat-Claude Bernard Hospital, Saint-Antoine Hospital, Assistance Publique-Hôpitaux de Paris, and colleagues assessed the presence of melanocytic nevi (moles) in 58 French children who were 8 or 9 years old at the time of the study. Eighteen children had phototherapy as newborns; 40 who were the same age but did not have phototherapy were recruited from a public school and served as controls. All the children and their parents were interviewed about the use of phototherapy, history of sun exposure and sunscreen use. A dermatologist performed physical examinations on the children and recorded their skin color, eye color, hair color, skin type and the number and size of moles.
Thirty-seven children (63 percent) had moles that were 2 millimeters or larger, and there was an average of 2.09 moles per child. Those who were exposed to phototherapy had significantly more moles of this size than those who did not—an average of 3.5 vs. 1.45 per child. When the analysis was limited to moles between 2 millimeters and 5 millimeters, the association was stronger. "Lentigo simplex [moles smaller than 2 millimeters in diameter] may represent more recent nevi, whereas those nevi due to early events should be larger," the authors write. "Nevi larger than 5 millimeters probably are congenital nevi and are most probably associated with genetic predisposition." These associations did not change when other risk factors for the frequency of moles, including skin type and light hair, were considered. Sun exposure, particularly during vacations, was also associated with the number of moles of all sizes, and light hair color was correlated with the number of moles smaller than 2 millimeters.
The study did not examine whether phototherapy increases the risk for melanoma in adults, and it is possible that the small difference in the number of moles between the two groups would not change their risk of developing cancer. However, further study could help illuminate the association. "Higher numbers of acquired benign nevi are associated with increased risk of melanoma," they conclude. "A detailed evaluation of the factors responsible for the development of nevi in children would be useful to identify high-risk groups to be targeted for prevention. The link between melanoma and phototherapy should be the focus of such a study."
(Arch Dermatol. 2006;142:1599-1604. Available pre-embargo to the media at www.jamamedia.org.)
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