Comparison of instrumental measurements of skin hydration

Skin hydration and the lack thereof can be measured either by an expert grader through visual assessments of flaking or biophysically by commercially available instruments that reportedly measure parameters related to skin hydration. This paper compares two of these instruments, the Corneometer 820 PC and the Skicon 200 Skin Conductance Meter, as to their abilities to measure skin hydration and correlate with skin dryness. The instruments are also compared with each other. In this study, repeated hand washing with soap was used to induce dry skin, and the parameter of skin flaking was assessed by an expert grader. Biophysical measurements of skin hydration using the Corneometer were taken as described by the manufacturer. Measurements with the Skicon were taken using its regular probe supplied with the instrument and a probe designed for the instrument by Measurement Technologies (MT Probe). The results indicated that both instruments had a significant correlation with the expert grader's evaluation of skin flaking. As flaking increased, instrumental measurements of skin hydration decreased. The best correlation occurred between skin flaking and either the Corneometer or the Skicon with the MT Probe. Furthermore, the instruments also significantly correlated with each other. In this case, the best correlation occurred between the regular probe and the MT Probe of the Skicon. The Corneometer and the Skicon with the MT Probe also have a high degree of correlation. Although these instruments are suitable to measure skin hydration, the Corneometer is more suitable for measuring decreases in skin hydration.