Dermal changes in progressive systemic sclerosis assessed by skin impedance measurements

Insufficient attention has been paid to the behaviour of minor resistance components in the deeper levels of the skin. The purpose of this work is to establish the existence of electrical changes in progressive systemic sclerosis (PSS), a cutaneous condition where the main changes are detectable in the dermis. This research was carried out with specially designed equipment which identifies the skin's locus of impedance. Ten female patients between 46 and 60 years of age (mean age 50 ± 6) and ten healthy female controls (42 ± 6) were investigated. Four electrodes, 4 cm from each other, were placed on the forearm to measure three electrical parameters: R(0), angle α, and R∞. While there was no significant diference in R(O) between PSS patients and controls and only a slight and insignificant increase in angle α, possibly due to slower metabolism and epidermal turnover in PSS, there was significantly higher R∞ in PSS vis-a-vis controls (P