Sea water or its components alter experimental irritant dermatitis in man

Background/aims: Ocean bathing has been considered "healthy" for skin, but its efficacy remains testimonial in nature. Our aim was to evaluate the eff ects of sea water and its main components on experimental irritant contact dermatitis induced by sodium lauryl sulphate (SLS) cumulative irritation. Methods: After open application of 2% SLS for 10 min on volar forearm sites , solutions of sea water, 500 mM NaCl, 10 mM KCI, 55 mM MgCl2, 10 mM CaCl2, or deionized water were separately applied using filter paper discs for 20 min. The procedures were repeated daily for 2 weeks. The effects of the tr eatment were assessed daily using measurements of transepidermal water loss (TEWL), as an indicator of epidermal barrier function, and capacitance, as a parameter of stratum corneum water content. Results: Sea water, NaCl, and KCI significantly inhibited the increase of T EWL as compared with deionized water (P<0.003, P<0.05, P<0.05, respectively ). Sea water and NaCl inhibited the decrease of capacitance as well (P<0.03 , P<0.01). Conclusion: The effect of sea water may be attributed to skin barrier prese rvation by NaCl and KCI, and an emollient effect by NaCl.