RESUMO
BACKGROUND: Inflammatory skin diseases were the most common problem in dermatology. This study aimed to develop a circuit by using a simple method for noninvasive, objective, and real-time skin inflammation screening. MATERIALS AND METHODS: Sprague-Dawley rats were used in this study. The rats were chemically induced to suffer from skin inflammation at the back of their left-hand side while the right-hand side of their back remained untreated serving as a control. Impedance (Z) spectrum of the rat's skin was recorded. RESULTS: Two characteristic frequencies (4.5 and 48.3 kHz) were found. At the two frequencies, the impedance of inflammatory skin tissue (ZIST ) was found to be significantly (P < .05) smaller than that of normal healthy skin tissue (ZNHST ). Moreover, the ratio of the impedance measured at 4.5 kHz (Zf = 4 .5 kHz ) to the impedance measured at 48.3 kHz (Zf = 48.3 kHz ), that is, Zf = 4.5 kHz /Zf = 48.3 kHz , was capable of skin inflammation screening. It was observed that the inflammatory skin tissue (IST) had the smaller value of Zf = 4 .5 kHz /Zf = 48.3 kHz (value < 8.5) and normal healthy skin tissue (NHST) had the higher value of Zf = 4 .5 kHz /Zf = 48.3 kHz (value ≈ 10) which almost remained constant. CONCLUSION: A circuit was developed which was used for measuring the skin impedance accurately at the two characteristic frequencies for skin inflammation screening.
