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.

Objective: 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.

Conclusions: 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.