Spinosad 0.9% Lotion for Scabies on Skin of Color: An Interventional Study by Polarized and UV-Induced Fluorescence...

Introduction Scabies, caused by Sarcoptes scabiei var. hominis, is a highly prevalent ectoparasitic infestation and a recognized neglected tropical disease. Increasing incidence, persistent post-treatment symptoms, and emerging resistance to conventional therapies such as permethrin necessitate effective alternative treatments. Spinosad 0.9% lotion, with known ovicidal and antiparasitic properties, has recently gained attention. This study evaluates its therapeutic efficacy using clinical and dermoscopic parameters, including polarized and ultraviolet-induced fluorescence (UVF) imaging. Materials and methods A hospital-based interventional case series was conducted at a tertiary care center from December 2025 to January 2026. Forty clinically and dermoscopically confirmed scabies patients were enrolled. Baseline demographic, clinical, and dermoscopic findings were recorded. Dermoscopy was performed using polarized and UVF modes to detect mites and burrows. Patients were treated with a single overnight application of spinosad 0.9% lotion. Follow-up assessment at three weeks included evaluation of clinical lesions (papules, nodules, pustules, excoriations) and dermoscopic signs (triangular jet sign, curvilinear tracks, and fluorescence). Statistical analysis was performed using SPSS, with p<0.05 considered significant. Results The study population had a mean age of 22±13.33 years, with a male predominance. Papules were the commonest lesions. Significant reduction was observed in papules (from 37, 92.5%, to five, 20%) with p<0.05; nodules (from 16, 40%, to one, 2.5%) with p<0.01; and pustules (from five, 12.5%, to none) with p<0.05 after treatment. Excoriations showed no significant change. Dermoscopic detection of mites decreased from 29 (72.5%) at baseline to nine (22.5%) at follow-up (p<0.05). Both polarized and UVF dermoscopy effectively demonstrated a reduction in mite-related features. No adverse effects were reported. Discussion Spinosad demonstrated significant clinical and dermoscopic efficacy, consistent with previous studies, and offers advantages such as single application and ovicidal activity. Persistent excoriations likely reflect ongoing post-scabetic pruritus rather than treatment failure. Dermoscopy proved to be a valuable objective tool for monitoring therapeutic response. Conclusion Spinosad 0.9% lotion is an effective, safe, and convenient alternative for scabies treatment, particularly in settings of resistance or poor compliance. Dermoscopic evaluation enhances diagnostic accuracy and treatment monitoring.