Dual Characteristics of Skin Care Creams Evaluated by Two In-Vivo Human Experimental Models

The use of skin care creams is a well documented protection measure to reduce the risk of barrier damage and contact dermatitis from exogenous contact with skin irritants. Before choosing a skin care cream two aspects should be considered: a) Is the product able to reduce irritant reactions caused by the irritant, and b) is the product well tolerated, also on damaged skin. Both aspects can be evaluated by experimental models in human volunteers. We used two standard experimental designs to compare six commercially available skin care products: a) the chamber scarification test, designed to assess the irritancy potential, and b) the repeated short-time occlusive irritation test (ROIT), developed to evaluate the efficacy of skin care creams. The results showed that a high score in the chamber scarification test for skin irritation was not necessarily correlated to the products' ability to impede sodium lauryl sulfate (SLS)-induced irritant skin reactions. Three products were shown to both have a low irritancy potential and be capable of reducing skin barrier damage induced by SLS, and one product had both an irritant potential on scarified skin and also a modest capability to reduce skin irritation induced by SLS. The use of both test methods, chamber scarification and ROIT, gives valuable information on skin compatibility and efficacy of skin care creams. The clinical relevance of the test results can only be determined by comparing products with high and low scores in both tests in controlled clinical experiments with subjects at risk of developing irritant contact dermatitis.