Analytic quantification of phototype-related regional skin complexion

Background/aims: Narrow-band spectrophotometry that yields melanin (M) and erythema (E) indexes is a convenient method for assessing skin colour. The objective of the study was to assess the phenotype-associated body site differences in skin complexion. Method: The Mexameter MX16 was used to record the skin colour in 137 subjects. Evaluations were made on the inner arm, volar forearm, dorsal forearm and forehead. Results: The inner arm and volar forearm had similar values for each of the colorimetric values. The dorsal forearm exhibited the highest M values, and the forehead had the highest E values. Significant positive linear correlations were found between M values from the distinct body sites. The E values showed a correlation only between the inner arm and the volar forearm. Conclusion: Regional skin colour differences are obvious. Sun-exposed skin does not react in the same way on the forearm and forehead. Regional variations in M can be predicted from the innate M value. In contrast, the regional variability in E is highly variable among subjects.