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Rhododendrol (RD) is a skin whitening ingredient that was developed in Japan. Among the 800,000 users of RD-containing cosmetics, 20,000 patients developed localized leukoderma (RD-induced leukoderma). Forty-two % of those users showed perilesional hyperpigmentation (leukomelanoderma), and 14% of them were associated with vitiligo vulgaris afterwards. The aim of this study is to investigate the risk factors affecting the severity of RD-induced leukoderma, the occurrence of leukomelanoderma, and the association with vitiligo vulgaris. For this retrospective cohort study, we abstracted data from our dermatology medical records of 101 patients who developed leukoderma after using the cosmetics containing RD from July 2013 to December 2014. Age, BMI, the number of RD-containing products they used, smoking history and depigmentation scores at their baseline visit as well as blood test data for anti-nuclear and/or anti-thyroid antibodies were analyzed. Multivariable logistic regression and linear regression were used for analyses of leukomelanoderma, vitiligo vulgaris and characteristics at the baseline visit. Age, the number of RD-containing products used, BMI, anti-nuclear and anti-thyroid antibodies were not significantly correlated with the presence of leukomelanoderma, but it appeared that leukomelanoderma was more likely to occur in patients who had a smoking history (p¼0.006). In addition, smokers showed a significant increase in their depigmentation score at the baseline visit (p¼0.03). Our study demonstrates that smoking is associated with the severity of RD-induced leukoderma and the occurrence of leukomelanoderma.

No abstract