A comprehensive comparison of facial skin hydration based on capacitance and conductance measurements in Chinese women.

OBJECTIVES: The aim of this study was to compare the data of conductance and capacitance measurements of facial skin hydration and to evaluate and discuss the advantages and disadvantages of the different approaches. METHODS: We measured skin capacitance (Corneometer® CM 825) and skin conductance (Skicon-200EX®) on 30 pre-defined facial sites of 125 Chinese women, resulting in 3750 readings per device. The data were analysed and compared, and continuous colour maps were generated on a 3D avatar for capacitance, conductance, relative difference (Δ%) and correlation (R-value) by interpolating between the individual readings and converting the values to colours. This visualization allows a better interpretation of the results. RESULTS: The complexity of facial skin hydration is revealed by this approach. The similarities and discrepancies in the facial hydration maps are clearly apparent. Due to the superiority of the Skicon in measuring high hydration levels, differences in skin hydration were evident on the forehead compared with the Corneometer maps, which may be related to the more superficial measurement of the Skicon within the stratum corneum. Conversely, a greater understanding of the complexity of facial skin hydration in the nasolabial fold was obvious when using the Corneometer. The best congruence between the instruments was found at two specific but separated facial areas, one around the inner eye region and the other one on a line between the nasolabial sulcus and the oblique, lateral jaw. Interestingly, the data were not normally distributed for both instruments and they had opposite skews. All facial clusters were statistically different from each other (p < 0.001), except the cheek and jaw for the Skicon. Larger than expected percentage coefficients of variance were found for the Corneometer on some facial sites that might be explainable by differences in stratum corneum physiology and biochemistry. Corneometer values of 48 AU and Skicon values of 132 µS were taken as the cutoff for normally hydrated facial skin. CONCLUSIONS: Both devices have their advantages and disadvantages suggesting that bio-instrumental measurement of skin hydration is actually more complicated than commonly thought and that the different facial zones and the use of multiple instrumentation have not been adequately considered.

OBJECTIFS: L'objectif de cette étude était de comparer des données issues de mesures d'hydratation de la peau du visage par conductance et capacité électrique, et d'évaluer et discuter les avantages et désavantages de ces différentes approches. METHODES: La capacité électrique de la peau (Corneometer® CM 825) et saconductance (Skicon-200EX®) ont été mesurées en 30 points pré-définis du visage de 125 femmes chinoises, menant ainsi à 3750 mesures par appareil. Les données ont été analysées et comparées, puis transposées visuellement sur avatar 3D via la création de cartographies continues de couleur par conversion de chaque valeur en une coordonnée de couleur et interpolation colorielle entre les différents points. Des cartographies de capacité électrique, de conductance ainsi que celle de la différence relative (Δ%) et de corrélation (R-value) ont été générées, ces visualisations permettant de mieux interpréter les résultats. RESULTS: Cette étude a mis en lumière la complexité de l'hydratation de la peau du visage. Les similarités et différences entre les cartographies d'hydratation faciale apparaissent clairement. Du fait de la supériorité du Skicon pour la mesure de hauts taux d'hydratation, des différences sont clairement visualisées entre les cartographies d'hydratation des deux appareils au niveau du front, et pourraient être dues à une mesure plus superficielle au sein du stratum corneum avec le Skicon. A l'inverse, l'utilisation du Corneometer permet une bien meilleure compréhension de la complexité de l'hydratation de la peau au niveau du sillon nasogénien. Les appareils montrent les résultats les plus similaires au niveau de deux zones spécifiques et séparées du visage, une au niveau du coin interne de l'œil et l'autre sur une ligne séparant le sillon nasolabial et l'oblique latéral de la machoire. Il est intéressant de noter que les distributions des données ne suivent pas une loi normale, pour aucun des deux appareils, et présentent des biais de distribution opposés. Tous les résultats obtenus au niveau des clusters faciaux étudiés montrent des différences statistiquement significatives entre eux (p⟨0.001), à l'exception de la joue et de la mâchoire, avec le Skicon. Des pourcentages de coefficients de variation plus élevés qu'attendus ont été obtenus avec le Corneometer en certaines zones du visage, qui pourraient être expliqués par des différences physiologiques et biochimiques du stratum corneum. Des valeurs de 48 UA avec le Corneometer et de 132 µS avec le Skicon ont été retenues comme valeurs seuil d'une peau du visage normalement hydratée. CONCLUSIONS: Les deux appareils montrent des avantages et désavantages, suggérant que la mesure bio-instrumentale de l'hydratation cutanée du visage est en réalité plus compliquée que communément admise et qu'une approche multiinstrumentale n'a pas été suffisamment considérée à ce jour pour appréhender les différentes zones du visages.

Anatomical site variation of water content in human skin measured by the Epsilon: A pilot study.

BACKGROUND: This pilot study aimed to investigate the anatomical site variation of water content of the stratum corneum (SC) on the body by measuring skin capacitance with the Epsilon, a new generation corneometer with multiple sensors. Secondly, values of the Epsilon were compared to values measured by conventional single sensor corneometers. METHODS: The hydration status of SC was measured in 15 healthy Caucasian volunteers with the Epsilon at five body sites (cheek, lower forearm, mid-calf, lower back and abdomen). Transepidermal water loss (TEWL) was measured with the Aquaflux to get more insight into the condition of the skin barrier. A literature search was performed to compare Epsilon values with conventional corneometers. RESULTS: The tested anatomical locations showed significant differences in water content (P < 0.001) with large interindividual variations; highest values were found in the cheek (11.64ε) and lowest values in the mid-calf (4.43ε). No correlation between water content and TEWL was found. In general, Epsilon values were lower compared to values of conventional corneometers, with a similar trend. CONCLUSION: This pilot study showed significant variations in water content at different skin locations measured by the Epsilon. Moreover, the Epsilon measured consistent lower values compared to single sensor corneometers. Further validation of the device is recommended.

The revised EEMCO guidance for the in vivo measurement of water in the skin.

BACKGROUND: Noninvasive quantification of stratum corneum water content is widely used in skin research and topical product development. METHODS: The original EEMCO guidelines on measurements of skin hydration by electrical methods and transepidermal water loss (TEWL) by evaporimeter published in 1997 and 2001 have been revisited and updated with the incorporation of recently available technologies. RESULTS: Electrical methods and open-chamber evaporimeters for measurement of TEWL are still the preferred techniques to measure the water balance in the stratum corneum. The background technology and biophysics of these instruments remain relevant and valid. However, new methods that can image surface hydration and measure depth profiles of dermal water content now available. Open-chamber measurement of TEWL has been supplemented with semiopen and closed chamber probes, which are more robust to environmental influence and therefore convenient to use and more applicable to field studies. However, closed chamber methods interfere with the evaporation of water, and the methods cannot be used for continuous monitoring. Validation of methods with respect to intra- and inter-instrument variation remains challenging. No validation standard or test phantom is available. RESULTS AND CONCLUSIONS: The established methods for measurement of epidermal water content and TEWL have been supplemented with important new technologies including methods that allow imaging of epidermal water distribution and water depth profiles. A much more complete and sophisticated characterization of the various aspects of the dermal water barrier has been accomplished by means of today's noninvasive techniques; however, instrument standardization and validation remain a challenge.

Correlação entre o efeito hidratante da ureia em diferentes concentrações de aplicação: estudo clínico e corneométrico / The skin moisturizing effects of different concentrations of urea: a clinical and corneometry study

Objetivo: Avaliar a correlação entre as diferentes concentrações e o efeito hidratante da ureia. Material e Método: Cada indivíduo recebeu aplicações de emulsões com 3%, 5% e 10% de ureia e uma emulsão controle. Realizaram-se avaliações clínicas, subjetivas e corneométricas em 1, 4 e 6 horas. Resultados: Todas as emulsões, incluindo a do controle, obtiveram efeito hidratante na primeira avaliação (p < 0,05). A ureia a 10% foi signifi cativamente superior às outras concentrações ­ na avaliação de 4 horas comparada à ureia a 3% e na avaliação de 6 horas, às concentrações de 3 e 5%. Formigamento e ardência foram mencionados para a ureia a 10% na avaliação de 1 hora. Conclusão: A duração das propriedades higroscópicas da ureia está positivamente relacionada com a concentração. Sintomas adversos, como ardência, foram observados apenas em maiores concentrações.

Objective: To evaluate the correlation from different concentrations and hydration effect of urea. Material and Method: A double blind, randomized, placebo-controlled clinical trial, with dry skin individuals submitted to one application of three different urea emulsion concentrations: 3%, 5% and 10%, and a control emulsion. Corneometry measures, clinical evaluation and a questionnaire at 1, 4, and 6 hours were developed. Results: All the emulsions, including the control, had a signifi cant moisturizing effect in the fi rst evaluation (p < 0,05); 10% urea is superior to other concentrations, which was observed at 4 hour evaluation against 3% urea, and at 6 hour evaluation against 5% and 3%. Itching and stinging were mentioned for 10% urea at 1 hour evaluation. Conclusion: The duration of urea hygroscopic properties is positively related with the concentration; adverse symptoms like stinging are observed only in higher concentrations.