Skin Hydration Measurement: Comparison Between Devices and Clinical Evaluations

Background: The need for an objective method for measuring skin hydration levels is becoming increasingly important. Various devices with different measuring principles for assessing skin hydration have been developed and are widely used. Objective: This study aimed to investigate the reproducibility and correlation between clinical evaluation and skin hydration measurement devices that are the most widely used in the field. Methods: A prospective comparative clinical trial was conducted on 184 healthy volunteers. Skin hydration levels were measured using the Corneometer (CM820) and hydration probe (HP: DermaLab Combo) at 3 points: the ventral forearm, the dorsal forearm, and the shin. We used the intraclass correlation coefficient (ICC) to evaluate the reproducibility and Pearson’s correlation coefficient (PCC) to evaluate the correlation of each measurement. Simple linear regression was used to analyze the Corneometer and HP skin hydration value changes according to changes in xerosis severity scale (XSS) values, which were evaluated by clinicians. Results: Both the Corneometer and HP showed significant, excellent reproducibility (ICC for Corneometer: 0.954–0.971, ICC for HP: 0.980–0.986) and significant high positive correlations (PCC: 0.708–0.737) regardless of the measurement site. Both devices showed negative regression coefficients in all measurement sites in XSS analysis, but this was not statistically significant. Conclusion: The Corneometer and HP were both accurate and objective skin hydration measuring devices, regardless of the measurement site. Using reliable and objective devices such as the Corneometer or HP can aid in understanding an individual’s skin condition and making more informed decisions for skin care.