Passive sustainable hydration of the stratum corneum following surfactant challenge

Surfactants exhibit a protein-denaturating potency which is responsible for water uptake and swelling of the stratum corneum. There is also an increas ed transepidermal water loss related to the alteration of the barrier funct ion. Ln the present prospective study, we evaluated sodium lauryl sulphate (SLS)-dependent changes in electrometric properties of skin. Single and ite rative SLS challenges were performed. Measurements were made using a NOVA D PM on continuous mode for 5 min in order to assess both the baseline surfac e hydration and the rate of changes during probe occlusion. The present non invasive instrumental evaluation of surfactant irritancy shows high sensiti vity in each subject, but suffers from large inter-individual variability i n the skin response following single and iterative sodium lauryl sulphate ( SLS) challenges. The baseline surface hydration, that is almost unaffected I h after removing SLS patches, significantly decreases after a lag time of 24 h. The rate of water accumulation in the stratum corneum during the pro be occlusion is significantly increased by SLS and is proportional to the S LS concentration and the number of iterative patches. Single water- or SLS- patch-tests fail to predict the skin response to cumulative SLS challenges and interindividual variability is large for all electrometric variables.