Combined Oral Ivermectin and 5% Permethrin Cream to Treat Severe Scabies

BACKGROUND: Severe scabies, a rare parasitic skin disease characterized by abundant skin mites, may be life-threatening and poses public health concerns worldwide. A combination of standard-dose oral ivermectin and topical scabicides is recommended for treatment. However, data from randomized clinical trials are lacking, and the probability of cure is uncertain. Ivermectin at higher doses has been effective in the treatment of some parasitic diseases. METHODS: We conducted a blinded randomized trial involving adults with severe scabies (i.e., profuse or crusted), as confirmed by parasitologic or dermoscopic assessment. The patients were assigned in a 1:1 ratio to receive oral ivermectin (to be taken with food) at a dose of 400 μg per kilogram of body weight (higher-dose group) or 200 μg per kilogram (standard-dose group) on days 0, 7, and 14, combined with head-to-toe application of 5% permethrin cream on days 0 and 7 and daily application (as recommended) of an emollient cream. The primary end point was cure of severe scabies, which was defined as the absence of mites and mite-related products (i.e., eggs and feces), as confirmed by parasitologic or dermoscopic assessment on days 18 and 21, and the absence of active clinical lesions on physical examination on day 28. RESULTS: A total of 132 patients (66 in each group) were included in the main analysis. Cure was observed in 75% of the patients in the higher-dose group and in 82% of those in the standard-dose group (odds ratio for cure, 0.64; 95% confidence interval, 0.25 to 1.67). No safety issues were identified. CONCLUSIONS: Among adults, the 400-μg-per-kilogram dose of ivermectin plus 5% permethrin cream was not superior to the standard 200-μg-per-kilogram dose of ivermectin plus 5% permethrin cream in curing severe scabies. (Funded by the French Ministry of Health and French Society of Dermatology; ClinicalTrials.gov number, NCT02841215.).