Differences among moisturizers in affecting skin susceptibility to hexyl nicotinate, measured as time to increase skin blood flow.

Abstract

Background/aims A wide range of branded and generic moisturizers is frequently used for the prevention and treatment of dry skin. The influence of moisturizers on the skin permeability is pertinent to the understanding of their therapeutic efficacy. The aim of the present study was to compare the effect of two moisturizers on the skin permeability barrier, assessed as skin reactivity to a vasodilating substance.Methods The study was parallel, randomized and double blind on 53 healthy volunteers. One of the creams contained 5% urea, whereas the other contained no humectant but had a high lipid content. The participants were instructed to apply the cream twice daily for three weeks on the volar aspect of one of their forearms. The skin was then exposed to hexyl nicotinate, which induces vasodilation. The time-course and magnitude of the microvascular changes in the two skin areas were monitored with a non-invasive optical technique (laser Doppler flowmetry) with two measuring probes.Results The lag-time between application and initial response was significantly longer for the urea-treated site compared with the other cream. Furthermore, the time for maximum response was shorter for the lipid-rich cream than for its placebo.Conclusion The study shows differences in action between moisturizers, which may influence the skin susceptibility to other irritants and allergens in the environment.