Videodermatoscopy enhances the ability to monitor efficacy of scabies treatment and allows optimal timing of drug application

Abstract

Videodermatoscopy (VD) is a noninvasive diagnostic tool that has recently been advanced as an alternative technique for the diagnosis of scabies, based on studies showing its ability to detect mites in vivo with results comparable to those obtained by traditional skin scraping. In this study we evaluated a group of patients undergoing topical treatment with a thermosensible foam containing 0.165% pyrethrins and 1.65% piperonyl butoxide to determine whether VD would enhance monitoring of the clinical response to treatment and indicate the optimal timing of drug application. Twenty patients (12 M, 8 F; age 1-65 years) affected by scabies (diagnosis confirmed by VD), and who were treatment naïve, were included in the study. The foam was applied to the entire body once a day at bedtime for two consecutive days. To detect treatment response, VD evaluation of two targeted skin sites for each patient was performed at baseline and at 12, 24, 36 and 48 h. A video microscope system equipped with a zoom lens that allowed skin observation with incident light at magnifications ranging from x 20 to x 600 was used. In all patients, VD showed active mite migration within burrows at 12 h. At 24 h, there was no evidence of active mite migration, and a majority of patients reported that itching had subsided. At 48 h, the mites were no longer visible in appreciable amounts by VD, and an amorphous material, probably resulting from mite decomposition, was detectable at one end of an empty burrow in the majority of patients. Skin scraping at 48 h, followed by standard microscopic observation, also showed only mite remnants in all patients. None of the 20 patients showed signs of infestation by VD at targeted skin sites at a 2-week post baseline follow-up visit. VD enhances the monitoring of clinical response to treatment and allows optimal timing of drug application. This may be particularly important in minimizing risk of overtreatment, reducing the potential for side-effects, and enhancing patient compliance.