Background The eggs of head lice are fixed to the hair of their hosts by means of a persistent glue-like fixative that is not chemically bound to the substrate. Eggshells stuck to hairs after successfully treating the infestation are a cosmetic issue and a source of misunderstanding about whether the infestation is eliminated. Hitherto, no effective treatment to loosen louse eggs and nits has been found. Methods An extensive screening of surface active compounds, oils, esters, and other cosmetic lubricants used a slip-peel device to measure the forces required to release the grip of the fixative. Promisingly effective compounds were formulated into suitable carriers for further testing. The most effective combination formulation was tested, as a commercial product (Hedrin Stubborn Egg Loosening Lotion), in a usage study of 15 children with nits, in which one half of the head was combed only on damp hair and the other half combed after a 10 min treatment using the product. Results Laboratory tests of the forces required to remove nits found that pelagonic acid derivatives, particularly isononyl isononanoate, in the presence of a polymeric gelling agent and water, were most effective to reduce the initial grip of the fixative as well as reducing friction as the eggshell is drawn along the hair shaft and that the final product was significantly (p < 0.05) more effective than several other marketed materials. In the usage study significantly (p = 0.01046) more louse eggs and nits were removed after treatment with the gel. Discussion The product developed through this study is the first with a demonstrable efficacy for loosening the grip of the louse egg fixative from hair. Consequently, until now, and despite the availability of effective pediculicidal treatments, dealing with the eggshells persisting after an infestation has been an onerous task for most households. This type of product can enable families to deal more easily with persistent eggshells and improve self-esteem in affected children.
Removing head louse eggshells and nits after a successful pediculicide treatment is often made more difficult because it is not easy to see them all amongst the hairs. Therefore, a treatment that makes louse eggs more visible potentially makes the task of removal easier and reduces the risk that children would be sent home from school or over-treated. This project involved the development of a hair treatment gel concept that was easy to apply, wash out, and that stained louse eggs and nits but without staining the hair and skin. A series of food-grade dyes were evaluated for their ability to stain the eggshells, and various copolymer-based rheology modifiers were tested for dye compatibility and stability. Several dyes were rejected because either they failed to stain louse eggshells or else stained skin too easily. Two dyes, Patent Blue and Ponceau 4R, were eventually selected for different product developments, one specifically for post-treatment nit removal and the other for pre-treatment diagnosis. In clinical field studies, both were found to make the treated eggshells contrast sufficiently with the hair to enable identification of persistent nits. Use of a nit stain product can enable easier detection of louse eggs and nits, thus facilitating the removal process and reducing the risk that persistent eggshells could be mistaken for signs of a continuing infestation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.