Allergic contact reactions in the skin assessed by electrical impedance - a pilot study

In our previous studies of the electrical impedance of the skin, we formulated a set of physical indices that could be used to distinguish between the cutaneous effects produced by different chemical irritants. We now describe an investigation of allergic contact reactions, using the same set of impedance indices for characterization.

Skin reactions were induced in the forearm of eight female patients who were allergic to nickel by exposure to nickel sulphate in petrolatum at various concentrations. The responses were evaluated by measurements of electrical impedance and transepidermal water loss, as well as by visual scoring and biopsy. Normal skin was used for controls.

Different degrees of allergic contact reactions were produced, and the changes in value of the impedance indices were found to follow a particular pattern. This pattern diverged markedly from that obtained in controls, and the differences were statistically significant.

Our results suggest that, by the application of a technique based on electrical impedance, it will be possible to characterize allergic skin reactions.