ABSTRACT
BACKGROUND: Human skin color shows variations throughout life and many extrinsic and intrinsic factors influence melanogenesis. The characteristics of skin pigmentation have been studied largely in white Caucasians. However, pigmentary changes due to various regulatory factors may be different in Orientals. OBJECTIVE: We observed the variations in skin color due to aging, seasonal changes and gender differences in Koreans with skin type IV or V. METHODS: Skin pigmentation was measured at five body sites (buttock, glabella, V-neck area, inner arm, and dorsal forearm) using skin reflectance spectroscope in 109 subjects in winter and summer. RESULTS: Constitutive pigmentation of the buttock was at the highest level in the first decade of life. It then decreased during the next two decades. This decreased level was maintained after the third decade. The pattern of pigmentation changes of other four sites with aging was similar to that of the buttock. Gender differences were significant except in the first decade. Seasonal change of pigmentation level was observed in dorsal forearm. Interestingly, our study did demonstrate some differences from the observations in Caucasians. We found that facultative pigmentation in Koreans was not increased with aging, so the sun exposure index was not reliable as a measure of cumulative lifetime UV exposure. CONCLUSION: These differences between races could imply that genetically determined basal skin color has important effects on characterizing later responsiveness to UV lights and sex hormones. Understanding these differences in skin pigmentation would be helpful in treating pigmentary diseases and skin cancers, and in studying the regulatory mechanisms of melanogenesis.