Multi-frequency bioelectrical impedance analysis of skin rubor with two-electrode technique

BackgroundSkin rubor, or reddish discoloration on skin, is a sign of irritation. Physiologically it involves temporary vasodilation and hyperaemia in tissue, and is diagnosed by the visible characteristics.PurposeBioelectrical impedance analysis (BIA) was tested to estimate skin rubor.MethodsFive healthy women (22–25 years) participated in the experiments. Four were ethanol patch test (EPT)-positive; one was negative. A skin rubor was developed on the subjects' left forearm by temporary vasodilatation, which was caused by a dermal inflammation reaction due to application of ethanol to the skin. BIA was then conducted for the skin rubor and the intact skin using a lock-in amplifier with a frequency range of 0.1 Hz–10 kHz. The impedance changes due to vasodilatation of capillary were evaluated.ResultsThe resistance of the skin rubor was found to decrease to almost 90% of the resistance and 87% of the reactance of the intact skin in the EPT-positive subjects. There was no impedance change in the EPT-negative subject. Through these experiments, skin rubor could be distinguished from intact skin based on the electrical impedance.ConclusionSkin rubor could be identified based on the bioelectrical impedance. This method would be used for various skin diagnoses due to simplicity and reliability of BIA.