Ivermectin versus benzyl benzoate applied once or twice to treat human scabies in Dakar, Senegal: a randomized controlled trial

OBJECTIVE: To compare the effectiveness of oral ivermectin (IV) and two different modalities of topical benzyl benzoate (BB) for treating scabies in a community setting. METHODS: The trial included patients aged 5-65 years with scabies who attended the dermatology department at the Institut d'Hygiène Sociale in Dakar, Senegal. The randomized, open trial considered three treatments: a single application of 12.5% BB over 24 hours (BB1 group), two applications of BB, each over 24 hours (BB2 group), and oral IV, 150-200 µg/kg (IV group). The primary endpoint was the disappearance of skin lesions and itching at day 14. If necessary, treatment was repeated and patients were evaluated until cured. Results were analysed on an intention-to-treat basis. A pre-planned intermediate analysis was carried out after the BB1, BB2 and IV groups had recruited 68, 48 and 65 patients, respectively. FINDINGS: At day 14, 33 patients (68.8%) in the BB2 group were cured versus 37 (54.4%) in the BB1 group and 16 (24.6%) in the IV group (P < 10-6). Bacterial superinfection occurred more often in the IV group than in the BB1 and BB2 groups combined (28% versus 7.8%, respectively; P = 0.006). At day 28, 46 patients (95.8%) in the BB2 group were cured versus 52 (76.5%) in the BB1 group and 28 (43.1%) in the IV group (P < 10-5). These clear findings prompted early study cessation. CONCLUSION: Topical BB was clearly more effective than oral IV for treating scabies in a Senegalese community.