Neem-silicone lotion and ultrasound nit comb: a randomised, controlled clinical trial treating head louse infestation

Abstract

Background: A neem-based conditioner lotion (ONC) used against head lice was previously tested clinically and shown to be relatively ineffective. To improve the activity against lice and their eggs, it was reformulated into a silicone vehicle (NNC) as part of a project to improve pediculicidal medical devices. An ultrasound nit comb was also developed to be used in conjunction with the neem lotion to remove louse eggs from the hair.Methods: A single-centre, parallel group, randomised, controlled, open-label community-based clinical study was set up to test the NNC lotion in comparison with a marketed product based on isopropyl myristate and cyclomethicone (IPM/C) with two treatments 7 days apart. In parallel, the lubrication effects of the NNC and ONC lotions were compared in use with the ultrasound comb. Results: For 134 randomised participants (50 NNC, 53 IPM/C, 17 NNC plus comb, and 14 ONC plus comb), the cure rate was 72.0% for NNC and 69.8% for IPM/C (OR 1.112, 95% CI, 0.47 to 2.61). Additional combing gave 82.4% cure using NNC and 28.6% using ONC (OR 11.67; 95% CI 2.13 to 64.04). No difference in efficacy of nit removal was detected although combing with conditioner was physically easier. Conclusions:One percent neem oil in silicone (NNC) is as effective to eliminate head lice as other silicone products. Nit combing is easier using a conditioner lubricant to facilitate sliding of the eggshells along hairs. Trial registration: Current Controlled Trials Registry ISRCTN77673809

Head louse egg and nit remover—a modern “Quest for the Holy Grail”

“…Although initially conditioner-like materials, such as the medium-long chain alkanols hexadecane-1-ol or octadecan-1-ol, were considered possible facilitators of louse egg release, it was not possible to improve on the activity previously observed. Similarly, the supposed lubricant effects of siloxane (silicone) oils, such as found in head louse treatment products, did not alter the initial force required to start louse eggs moving along hairs confirming previous observations (Burgess, Brunton & Burgess, 2016; Burgess et al, 2017). Some other “oily” materials were found to reduce the mean Peak Force measured over a batch of louse eggshells, particularly some alkyl esters and emollient surfactants, although there was considerable variation of effect between compounds and some showed more variance of the Peak Force within a batch of eggs than when removing eggs from dry hair, examples of which are shown in Fig.…”

“…For a study of a commercially available cosmetic or Class 1 medical device product, used for its intended purpose, there is no requirement or procedure in the United Kingdom to seek ethical approval through the National Research Ethics Service (see http://www.hra-decisiontools.org.uk/ethics/). However, the protocol employed was based on a protocol previously submitted by us to Huntingdon Local Research Ethics Committee (07/Q0104/44) for a similar procedure (Burgess et al, 2017) and was internally reviewed by the sponsor prior to being commissioned. The actual methodology of combing followed that used in a previously published study conducted elsewhere (Gallardo et al, 2013).…”