Electrical Measurement of the Hydration State of the Skin Surface in Vivo

Abstract

Decreased water content in the horny layer leads to loss of flexibility and elasticity [1]. Since deeper portions of the stratum corneum are well hydrated by direct diffusion of water from the underlying living epidermis, the state of hydration for the superficial portion of the stratum corneum plays a crucial role in governing the suppleness and softness of the skin. Therefore, when the superficial portion of the stratum corneum becomes dry and brittle in a dry atmosphere, even normal skin surface may develop fine cracks and flakes in areas prone to body movement. Scaling or cracking observed in various dermatoses is thought to develop as a result of a pathological horny layer which is deficient in water-holding capacity. Although we know this from our clinical observations, we have lacked methods that could quickly furnish scientifically sound, quantitative information on the state of hydration of the skin surface in vivo, similar to the relative simplicity of measuring the water content in stratum corneum in vitro.

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This work was supported by Grant-in-Aid for Scientific Research 5687007 from the Ministry of Education, Japan and by a research grant from Japan’s Lydia O’Leary Memorial Foundation