PracticeUpdate: Dermatology - Winter 2018

EXPERT OPINION 21

application of permethrin with a 1-week interval is superior to a single dose of iver- mectin; however, it must be noted that this difference was not significant (P = .42). 4 In a systematic review of 15 randomized controlled trials, which involved 2172 patients (several with variable dosing schedules – please read reference 5 for details), Dhana et al found that oral iver- mectin was associated with a significantly increased risk of treatment failure com- pared with topical permethrin (RR, 1.33; treatment failure rate, 14% [122/860] vs 10% [85/831]). 5 Dressler et al, in their systematic review of 16 studies, found three compar- isons of topical and systemic therapies. A total of six trials reported findings after 2 and/or 4 weeks on the efficacy of topical permethrin versus systemic ivermectin. Effi- cacy was comparable, although the trials differed in terms of their outcome parame- ter and other factors. Frequency of repeat treatment was inadequately reported. 6 In conclusion, I am not yet convinced that there is any significant therapeutic advan- tage to either oral ivermectin or topical permethrin. Certainly, there will be times when topical permethrin will be indicated over ivermectin, most notably in children under 15 kg or during pregnancy. 7 In severe cases, if without contraindication, it may make sense to use both oral ivermectin and permethrin simultaneously. Recom- mendations may change over time based on drug resistance patterns. In the mean- while, should I get scabies again, I’m taking the pill. Disclaimer: First published on Dr. Warren Heymann’s Dermatology Insights and Inquiries website on February 1, 2018. Republished with 1. Khalil S, Abbas O, Kibbi AG, Kurban M. Scabies in the age of increasing drug resistance. PLoS Negl Trop Dis 2017;11(11):e0005920. 2. Powell JB, Tucker WFB. Scabies. In: Lebowohl MG, Heymann WR, Berth-Jones J, Coulson I (eds). Treatment of Skin Disease, fifth edition, 2018, Elsevier, Ch. 223. 3. Manjhi PK, Sinha RI, Kumar M, Sinha KI. Comparative study of efficacy of oral ivermectin versus some topical antiscabies drugs in the treatment of scabies. J Clin Diagn Res 2014;8(9):HC01-HC04. 4. Goldust M, Rezaee E, Hemayat S. Treatment of scabies: Comparison of permethrin 5% versus ivermectin. J Dermatol 2012;39:545-547. 5. Dhana A, Yen H, Okhovat JP, et al. Ivermectin versus permethrin in the treatment of scabies: A systematic review and meta-analysis of randomized controlled trials. J Am Acad Dermatol 2018;78(1):194-198. 6. Dressler C, Rosumeck S, Sunderkötter C, et al. The treatment of scabies. Dtsch Arzebl Int 2016;113(45):757-762. 7. Hill TA, Cohen B. Scabies in babies. Pediatr Dermatol 2017;34(6):690-694. www.practiceupdate.com/c/65947 permission. References

" I am not yet convinced that there is any significant therapeutic advantage to either oral ivermectin or topical permethrin. Certainly,

of the first and sixth weeks. The efficacy of ivermectin, permethrin, GBHC, and BB lotion, using improvement in severity of pruritus as a parameter, was 85%, 90%, 75%, and 68.33%, respectively, at second follow-up. Similarly, considering improve- ment in severity of lesion as parameter, results were 80%, 88.33%, 71.66%, and 65%, respectively, at second follow-up. Topical permethrin (5%) was more effec- tive as compared with topical BB lotion and topical GBHC lotion (P < .05; significant), but statistical difference between efficacy of topical permethrin and oral ivermectin was nonsignificant (P > .05). This suggested that oral ivermectin and topical permethrin (5%) were equally efficacious. 3 Goldust et al evaluated 242 patients with scabies who were divided into two groups randomly. The first group and their family contacts received 5% permethrin cream and the other received oral ivermec- tin. Treatment was evaluated at intervals of 2 and 4 weeks. A single dose of iver- mectin provided a cure rate of 85.9% at a 2-week interval, which increased to 100% after crossing over to the permethrin group at a 4-week interval. Twice applica- tion of permethrin with a 1-week interval was effective in 92.5% of patients, which increased to 94.2% after crossing over to the ivermectin group at a 4-week interval. Permethrin-treated patients recovered earlier. The authors concluded that twice

be effective against the ova; hence, the reason why repeat dosing is often needed in practice and shows improved cure rates in studies.” 2 Searching PubMed utilizing “permethrin versus ivermectin for scabies,” I found two relevant studies. Manjhi et al conducted a study on four groups, including 60 scabetic patients in each group by simple random sampling. Treatments included the fol- lowing: group 1 – ivermectin (200 μg/kg body weight) oral in a single dose; group 2 – topical permethrin 5% cream single appli- cation; group 3 – topical gamma benzene hexachloride (GBHC) lotion 1% single application; and group 4 – topical benzyl benzoate (BB) lotion 25% single applica- tion. All of the patients were followed for improvement in terms of severity of dis- ease and severity of pruritus at the end there will be times when topical permethrin will be indicated over ivermectin, most notably in children under 15 kg or during pregnancy. "

VOL. 2 • NO. 3 • 2018