Permethrin and Ivermectin Both Effective Against Scabies

Lara C. Pullen, PhD

March 08, 2012

March 8, 2012 — Permethrin may be slightly more effective than ivermectin in the treatment of scabies. In a study involving 272 patients, a single dose of ivermectin provided a cure rate of 85.9% at 2 weeks compared with a 92.5% cure rate at 2 weeks from 2 applications (at a 1-week interval) of permethrin. The difference was not statistically significant (P = .42) in this noninferiority trial.

Mohamad Goldust, MD, from Tabriz University of Medical Sciences, Iran, and colleagues report the results of their study comparing the efficacy of oral ivermectin with topical application of permethrin in the treatment of scabies in an article published online March 5 in the Journal of Dermatology. The authors found not only a slightly higher cure rate with permethrin but also that permethrin-treated patients recovered earlier.

The cure rate from ivermectin increased to 100% after patients were treated with permethrin after a 4-week interval, according to the authors. Treatment with ivermectin after permethrin increased the cure rate to only 94.2%.

The authors suggest that a single dose of ivermectin may not be effective because it fails to act against the organism at all stages of its life cycle. Although permethrin attacks both the adult organism and its eggs, ivermectin attacks only the adult organism.

The study included 272 patients with scabies who visited the dermatology outpatient department at Sina Hospital in Tabriz, Iran, between April 2008 and April 2011. Of these patients, 30 were lost to follow-up. The remaining 242 patients' ages ranged from 3 to 78 years (mean age, 36.2 ± 12.6 years).

Half of the patients and their family contacts received 5% permethrin cream, and the other half received oral ivermectin. The patients were evaluated at 2 and 4 weeks posttreatment.

Scabies is a highly contagious skin disease caused by the mite Sarcoptes scabiei. Scabies results in substantial morbidity from secondary infections and postinfective complications such as poststreptococcal glomerulonephritis. Lindane has been the preferred therapy for scabies for the last 50 years, and lindane has become the most widely used antiscabietic drug in Iran and other countries.

Resistance to lindane has risen, however, and there are now reports worldwide of several clusters of patients with lindane-resistant scabies. Ivermectin and permethrin were introduced as alternative treatments for scabies.

The authors have disclosed no relevant financial relationships.

J Dermatol. Published online March 5, 2012. Abstract