On the course of the irritant reaction after irritation with sodium lauryl sulphate.

BACKGROUND: The sodium lauryl sulphate (SLS) irritation test is a well-established model for irritant contact dermatitis after the effects of surfactants. AIM OF THE STUDY: The course of changes in corneometric measurements (stratum corneum hydration), in transepidermal water loss (TEWL), in laser Doppler measurements (epidermal perfusion) and in colorimetric measurements (skin redness), after a single SLS irritation, should be studied over time. METHODS: Twenty healthy volunteers were studied. Irritation with 1% SLS solution was applied to the side of one forearm for 24 h under occlusive conditions, while the symmetrical experimental site remained untreated. Measurements were made for 9 days after completion of SLS irritation. RESULTS: Stratum corneum hydration was reduced immediately after irritation, and subsequently a hyper-hydration was observed. The increase in TEWL, laser Doppler measurements and skin redness persisted for 7-9 days. With regard to skin redness, a mild blanching effect was noticeable after 9 days. DISCUSSION: The evidence of very short-term exsiccation of the stratum corneum with persistent barrier damage, as well as reactive hyper-hydration and blanching of the skin, is remarkable. These first findings suggest that exsiccation of the stratum corneum is not caused by a damage to barrier lipids.

Cleansing, dehydrating, barrier-damaging and irritating hyperaemising effect of four detergent brands: comparative studies using standardised washing models.

UNLABELLED: BACKGROUND AND PROBLEM: It is well known that the damaging effect of surfactants on the stratum corneum varies according to the surfactant used. The present investigations aim to compare four standard commercial cleansing solutions (Esemptan Cleansing Lotion, Stephalen Shower Gel, Manipur Antimicrobial Cleansing Solution and Tork Mevon 55 Liquid Soap) with respect to their cleansing and skin barrier-damaging effects. MATERIAL AND METHODS: The cleansing effect of the solutions was determined in relation to their concentrations in a first experimental series involving 15 subjects using a standardised test method. The product concentrations with the most divergent cleansing effects were tested for their dehydrating (corneometry), epidermal barrier-damaging (TEWL) and irritating effects (laser Doppler) in a standardised washing test. In a second experimental series, the concentration used for the cleansing solutions was based on the quantity of cleansing solution obtained from dispenser actuations (six actuations/L). These concentrations were used to test the cleansing and damaging effect on the stratum corneum using the same methods as in the first experimental series. RESULTS: There were no significant differences in the first experimental series. In the second experimental series, Stephalen Shower Gel showed disadvantages in terms of a small cleansing effect, but without evidence of a smaller stratum corneum-damaging effect, and Tork Mevon 55 Liquid Soap showed advantages in terms of a smaller stratum corneum-damaging effect, but without evidence of a smaller cleansing effect. CONCLUSIONS: These studies showed that the relationship between the cleansing and the damaging effect on the stratum corneum can be properly assessed only by testing different concentrations. Furthermore, this experimental approach allowed to differentiate the four tested cleansing solutions.