Ivermectin and permethrin for treating scabies

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Stefanie Rosumeck 1, Alexander Nast 2,  Corinna Dressier 2

1. Division of Evidence Based Medicine, Department of Dermatology, Venerology and Allergology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, Berlin, Berlin, 10117, Germany

2. Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Division of Evidence Based Medicine, Department of Dermatology, Venerology and Allergology, Berlin, Berlin, Germany

Rosumeck SNast ADressler CIvermectin and permethrin for treating scabiesCochrane Database of Systematic Reviews 2018, Issue 4. Art. No.: CD012994. DOI: 10.1002/14651858.CD012994

Access the full text article here: DOI: 10.1002/14651858.CD012994/full

Ivermectin and permethrin for treating scabies

What is the aim of this review?

The aim of this Cochrane Review was to assess the efficacy and safety of topical permethrin and topical or systemic ivermectin for scabies in people of all ages. We searched for all relevant studies to answer this question and found 15 studies, which we collected and analysed.

Key messages

We found that for the most part, there was no difference detected in the efficacy of permethrin compared to systemic or topical ivermectin. Overall, few and mild adverse events were reported. Our confidence in the effect estimates was mostly low to moderate. Poor reporting of studies was a major limitation.

Additional high-certainty studies are needed to strengthen the confidence in the results and improve the evidence base.

What was studied in the review?

Scabies is an intensely itchy parasitic infection of the skin. It occurs throughout the world, but is particularly problematic in areas of poor sanitation, overcrowding, and social disruption. In recent years, permethrin and ivermectin have become the most relevant treatment options for scabies.

We examined topical permethrin, topical ivermectin, and systemic ivermectin as a treatment for scabies in women and men of all ages. We assessed efficacy as complete clearance of skin lesions at different time points after the start of the treatment. Other outcomes were the number of participants re-treated, the number of participants with at least one adverse event, and the number of participants who stopped participating in the study because they experienced an adverse event.

What are the main results of the review?

We found 15 relevant studies. Nearly all studies were set in South Asia or North Africa. These studies compared systemic ivermectin with topical permethrin, topical ivermectin with topical permethrin, or systemic ivermectin with topical ivermectin to treat people with scabies. All studies were conducted at a single centre with mostly small numbers of participants per study group.

Oral ivermectin may lead to slightly lower rates of complete clearance after one week compared to permethrin cream (low-certainty evidence), but little or no difference in rates of complete clearance by week two (low-certainty evidence). Treatments with one to three doses of ivermectin or one to three applications of permethrin may lead to little or no difference in rates of complete clearance after four weeks (low-certainty evidence).

There is probably little or no difference in complete clearance rates after one week of treatment with oral ivermectin or one application of permethrin lotion (moderate-certainty evidence).

There is probably little or no difference in rates of complete clearance between systemic ivermectin at standard dose and topical ivermectin lotion four weeks after initiation of treatment (moderate-certainty evidence). Likewise, after four weeks, ivermectin lotion probably leads to little or no difference in rates of complete clearance when compared to permethrin cream (moderate-certainty evidence), and there is little or no difference among treatments with systemic ivermectin in different doses (high-certainty evidence).

No participants in the systemic ivermectin or the permethrin group stopped participating in the study because they experienced an adverse event (moderate-certainty evidence). Two weeks after treatment initiation, there is probably little or no difference in the proportion of participants treated with systemic ivermectin or permethrin cream who experienced at least one adverse event (moderate-certainty evidence). After four weeks, ivermectin may lead to a slightly larger proportion of participants with at least one adverse event (low-certainty evidence).

Adverse events in participants treated with topical ivermectin were rare and of mild intensity and comparable to those with systemic ivermectin. For this comparison, it is uncertain whether there is any difference in the number of participants with at least one adverse event (very low-certainty evidence). No participants in the topical or systemic ivermectin group stopped participating in the study because they experienced an adverse event (moderate-certainty evidence).

It is uncertain whether topical ivermectin and permethrin differ in the number of participants with at least one adverse event (very low-certainty evidence). We found no studies comparing one dose versus two doses of systemic ivermectin that assessed safety outcomes.

How up-to-date is this review?

We searched for studies published up to 25 April 2017.