Application errors associated with topical treatment of scabies: an observational study

Abstract

Summary Background In recent years, there has been a significant increase in scabies infestations throughout German‐speaking countries. Given the high frequency of treatment failures, the question arises as to whether topical permethrin treatment is always performed correctly. Patients and methods Our department uses a fluorescent test cream to teach patients on how to correctly apply topical permethrin. In the context of a prospective observational study of 21 patients, we systematically assessed and analyzed potential application errors. Results None of the participants succeeded in adequately applying the cream to the entire skin as previously instructed. The median number of regions left untreated was six (minimum: 2; maximum: 18), which included a median body surface area of 6 % (minimum: 2 %; maximum: 30 %). With regard to predilection sites of scabies, the ankles were left untreated in 62 % of cases, followed by the interdigital spaces (toes) (33 %) and the sacral region (24 %). All patients considered the pretreatment training to be very useful. Conclusions The present findings clearly demonstrate potential shortcomings when it comes to the application of topical antiscabies treatment. This may provide a (potentially underestimated) explanation for the large number of reports on treatment failures in this regard, which falsely suggest potential treatment resistance.

Comparison of topical benzyl benzoate vs. oral ivermectin in treating scabies: A randomized study

“…which might be explained by the assumption that this age class is negligent in following all instructions regarding treatment and hygienic measures correctly and has frequent skin contacts with potentially afflicted peer-groups, partners or siblings. 27 However, this observation could be biased due to the proportionally larger cohort in this age class. A similar explanation can be considered for children of families with many children, where refractory infestations were observed more frequently.…”

“…Further, regardless of the antiscabietic medication used, patients up to 25 years were more prone for treatment failure, which might be explained by the assumption that this age class is negligent in following all instructions regarding treatment and hygienic measures correctly and has frequent skin contacts with potentially afflicted peer‐groups, partners or siblings 27 . However, this observation could be biased due to the proportionally larger cohort in this age class.…”

Study of the Use of Permethrin 5% Cream in Galicia (Spain) between 2018 and 2021

“…There are several possible explanations for our findings. The main reason could be treatment failure, which has generally been attributed to various causes, such as incorrect application of the cream by patients, failure to simultaneously treat cohabitants, or insufficient disinfection of the environment [ 26 , 27 , 28 ]. However, an increasing number of dermatologists are suggesting a real resistance to permethrin after ruling out the previously described errors and achieving a cure with other active principles for topical use, including magistral preparations, such as sulfur in an ointment base (petrolatum) or benzyl benzoate [ 29 ].…”

Prescriptions for scabies are rapidly increasing in Spain: An ecological study with national prescription data, 2008–2021

“…Moreover, we could not retrieve prescription data per individual, and many patients are likely to have received repeated treatments. Concern for a potential loss of efficacy of topical permethrin 1 has been reported, although inadequate application by the patient might account for treatment failures, 9 leading to repeated treatments. Additionally, scabies on atypical areas like the face has recently been reported among immunocompetent adults, 10 which might be further limiting permethrin effectiveness, as patients are not consistently instructed to treat these areas.…”