Baseline electrical impedance measurements at various skin sites - related to age and sex

Background/aims: During previous studies on the electrical impedance of the skin, we formulated a set of four physical indices that could be used to distinguish between the cutaneous effects produced by different chemical irritants. We now employ the electrical impedance technique to compare the properties of different anatomical areas of the skin, using the same set of indices. Methods: Investigations were performed on 131 healthy volunteers, who were divided into four groups on the basis of age and sex. Readings of electrical impedance were taken from ten different regions over the body, and transepidermal water loss was measured for comparison. Results: Baseline values of electrical impedance of the skin were shown to vary, depending on the site. Age was also found to exert a major influence, causing an increase in the indices related to magnitude (MIX, RIX, and IMIX) with increasing age, and a decrease in that related to phase (PIX), while sex had only a marginal effect. Conclusions: As with other non‐invasive techniques, baseline characteristics differ from place to place over the body surface, and age is another important determining factor.