Quantitative characterization and study of the relationship between constitutive-facultative skin color and phototype in Caucasians

In this study constitutive and facultative colorimetric values were quantif ied to determine the physiologic changes in Caucasian skin color and to def ine the correlation between skin color and phototype assessed according to the Fitzpatrick method. Our population consisted of 401 subjects ranging in age from 24 to 28 years with similar life styles. Skin color was measured with a Minolta CR-200 colorimeter on the upper medial quarter of the buttoc k (constitutive color) and on the cheek (facultative color), Advanced multi variate statistical analysis allowed differentiation between constitutive a nd facultative skin color in relation to the phototype to be quantified. Mo reover, Kullback divergence showed that the probability of correctly determ ining a subject's phototype is high when the variables of constitutive and facultative skin color are considered together. This interesting result mak es it possible, in the future, to use colorimetric values of exposed and no nexposed skin, together with determination of Fitzpatrick phototype and of other phenotypic characters, to better predict cutaneous sun reactivity.