The Treatment of Scabies

Abstract

Background: Scabies is a contagious infestation transmitted by skin-to-skin contact and sometimes by contact with contaminated material. The scabies mite burrows into the skin, producing a papular rash and severe itch at typical sites of predilection.

Methods: We systematically reviewed the literature to compare the efficacy of various anti-scabies agents, including a calculation of relative risks and confidence intervals.

Results: A literature search yielded 596 initial hits; after screening in accor-dance with the defined inclusion and exclusion criteria, 16 studies were selected for this review. Among topical treatments for scabies, permethrin was equally effective or more effective than crotamiton or benzyl benzoate. In a comparison of topical versus systemic treatment, topical permethrin and systemic ivermectin did not differ substantially in efficacy (7 comparative studies revealed no difference; one revealed a difference in favor of permethrin). Comparative trials of topical benzyl benzoate versus systemic ivermectin yielded inconsistent findings. Single and double administrations of ivermectin were similarly effective. In trials involving entire populations with a high prevalence of scabies, systemic ivermectin was found to be superior to topical permethrin.

Conclusion: There are hardly any differences in efficacy between the available treatments for scabies. Single administrations of permethrin 5%, crotamiton 10%, and systemic ivermectin are all comparably effective. There are differences in the frequeny and ease of application as well as when eradicating scabies in populations with a high prevalence.

Figure

Light microscopy images of Sarcoptes scabiei

Figure

Study selection process

eFigure 1

Efficacy of permethrin 5% versus crotamiton 10% after 4 weeks *10 children in the CRO group had undergone repeat treatment. 95% CI: 95% confidence interval

eFigure 2

Efficacy of single-dose permethrin 5% (PER) vs. single-dose ivermectin 0.2 mg/kg (IVER) after 2 weeks *¹ 17.8% (PER) and 44.4% (IVER) of patients underwent repeat treatment after 1 week; in the other trials, there were no repeat treatments within 2 weeks. *² Ivermectin arms combined.

eFigure 3

eFigure 3: Efficacy of single-dose permethrin 5% (PER) vs. 1 or 2 doses of ivermectin (IVER) 0.2 mg/kg after 4 weeks *¹ Patients not successfully cured underwent repeat treatment (weeks 1 to 4; n/N not reported). *² Patients not successfully cured underwent repeat treatment (week 2; n/N not reported). *³ All patients were treated every 2 weeks. *⁴ One patient in the PER group and 12 patients in the IVER group underwent repeat treatment after 2 weeks. *⁵ All patients were treated every 2 weeks.

eFigure 4

Efficacy of ivermectin (IVER) 0.15 to 0.2 mg/kg (single dose) vs. benzyl benzoate (BB) 10%/12.5%/25% (1 or 2 doses) after 2, 3 [4.1.1 to 4.1.6], and 4 weeks [4.1.7 to 4.1.10] *¹ Treatment repeated on day 7 if condition worsened (IVER: 8 patients). *² See above. *³ 44.4% (IVER) and 24% (BB) of patients underwent repeat treatment after 1 week if there were no signs of improvement. *⁴ Treatment repeated on day 7 (IVER: 8 patients) and day 14 (n/N not reported) if condition worsened. *⁵ Treatment repeated on day 7 (IVER: 8 patients) and day 14 (n/N not reported) if condition worsened.

eFigure

Risk of bias for each included trial The risk of systematic bias of trial findings was evaluated using the Cochrane Risk of Bias Assessment Tool.