Electrical impedance for quantification and classification of experimental skin reactions.

BACKGROUND

Pathophysiologic events in biological tissue are characterized by a shift of the electrical impedance spectra of the tissue under study.

OBJECTIVE

To discuss studies on experimental skin reactions with an improved impedance spectrometer. The instrumentation is related to noninvasive techniques based on other physical principles.

METHODS

The results from studies on patients with allergic contact reactions (n = 8), prick tests (n = 10), and irritant contact reactions (benzalkonium chloride [n = 14], sodium lauryl sulfate [n = 12], and nonanoic acid [n = 14]), and an appropriate number of controls are reviewed.

RESULTS

Results show statistically significant changes of the impedance parameters when compared with relevant controls, at different types of experimental cutaneous reactions, both allergic and irritant type. Each reaction type had a specific impedance index pattern.

CONCLUSIONS

Current data indicate that the improved impedance technique offers a possible noninvasive alternative for characterization and perhaps differentiation, not only between the skin responses induced by either an allergen or an irritant, but also a capability to distinguish responses induced by chemically different irritants. The assumption that the impedance method is capable to distinguish allergic from irritant contact reactions has not been proven yet in direct comparative studies.