High-frequency conductance measurement of the skin surface hydration state of dry skin using a new probe studded with needle-form electrodes (MT-8C).

Abstract

When high-frequency conductance measurements are performed on dry scaly skin such as atopic xerosis, senile xerosis or psoriasis, the values recorded with a flat surfaced ordinary probe tend to be lower, indicating a reduced hydration state, than the actual one, because the rough and firm skin surface prevents close contact with the hard and flat surface of the applied probe. We evaluated the usefulness of an MT-8C probe (Measurement Technologies Cincinnati, USA), whose skin-attaching portion is studded with 8 needle-like electrodes instead of a flat surfaced type, for measurments on dry skin. The MT-8C probe yielded conductance values slightly higher than those recorded with the flat surfaced probe attached to Skicon in measuring the hydration state of moderately dry skin surface such as atopic xerosis and senile xerosis. It seems to be comparable or more sensitive than the capacitance recording with the Corneometer. The recorded values obtained with the MT-8C probe showed more variations than the latter because of its higher sensitivity and much smaller contact area, that makes it difficult to touch to the same spots repeatedly. No such a difference was observed on severely dry skin and thickly scaly psoriatic lesions.