A novel continuous colour mapping approach for visualization of facial skin hydration and transepidermal water loss for four ethnic groups

• Published in: International journal of cosmetic science 2015-12, Vol.37 (6), p.595-605
• Main Authors: Voegeli, R., Rawlings, A. V., Seroul, P., Summers, B.
• Format: Article
• Language: English
• Subjects: Color; Cross-Sectional Studies; Epidermis - physiology; ethnic; Ethnic Groups; Face; facial colour mapping; Humans; skin barrier; skin hydration; stratum corneum; transepidermal water loss; Water
• ISSN: 0142-5463; 1468-2494
• DOI: 10.1111/ics.12265

Synopsis Objectives The aim of this exploratory study was to develop a novel colour mapping approach to visualize and interpret the complexity of facial skin hydration and barrier properties of four ethnic groups (Caucasians, Indians, Chinese and Black Africans) living in Pretoria, South Africa. Methods We measured transepidermal water loss (TEWL) and skin capacitance on 30 pre‐defined sites on the forehead, cheek, jaw and eye areas of sixteen women (four per ethnic group) and took digital images of their faces. Continuous colour maps were generated by interpolating between each measured value and superimposing the values on the digital images. Results The complexity of facial skin hydration and skin barrier properties is revealed by these measurements and visualized by the continuous colour maps of the digital images. Overall, the Caucasian subjects had the better barrier properties followed by the Black African subjects, Chinese subjects and Indian subjects. Nevertheless, the two more darkly pigmented ethnic groups had superior skin hydration properties. Subtle differences were seen when examining the different facial sites. Conclusions There exists remarkable skin capacitance and TEWL gradients within short distances on selected areas of the face. These gradients are distinctive in the different ethnic groups. In contrast to other reports, we found that darkly pigmented skin does not always have a superior barrier function and differences in skin hydration values are complex on the different parts of the face among the different ethnic groups. Résumé Objectif Le but de cette étude exploratoire était de développer une nouvelle approche de cartographie couleur pour visualiser et interpréter la complexité de l'hydratation de la peau du visage et de ses propriétés barrières à travers quatre ethnies (caucasienne, indienne, chinoise et noire africaine) vivant à Pretoria, Afrique du Sud. Méthodes Nous avons mesurés la perte insensible en eau (TEWL: transepidermal water loss) et la capacitance de la peau sur 30 régions prédéfinies du front, de la joue, de la mâchoire et de l'œil de seize femmes (quatre par ethnie) et avons réalisé des images numériques de leur visage. Une cartographie couleur exhaustive du visage a été générée en interpolant les valeurs entre chaque région mesurée et en la superposant à l'image numérique. Résultats La complexité de l'hydratation de la peau du visage et de ses propriétés barrières sont révélées grâce à ces mesures et visualisées