Skin impedance in psoriatic epidermis

Three electrical parameters derived from a measurement of skin impedance have been examined in this in vivo study of psoriatic epidermis. The stratum corneum's barrier function was measured by R ₀, epidermal metabolic activity by angle α and the resistance of deeper tissues by R(∞). Skin impedance was measured in both pathological and apparently normal skin in ten psoriatic patients and was compared with similar measurements carried out in thirteen controls. The comparison revealed considerable differences in angle α between psoriatic plaque, apparently normal skin in psoriatic patients and healthy skin in the control group. While there were no significant differences as regards R(∞), there was a significant decrease in R ₀ in psoriatic patients when compared with controls. Electrical parameters would therefore seem to be useful in characterising psoriatic epidermis.