Detection of skin irritation potential of cosmetics by non-invasive measurements

This study analyses the ability of four noninvasive techniques (laser Doppl er velocimetry, evaporimetry, chromametry and corneometry) to discriminate between irritant and non-irritant products, when compared to appropriate co ntrols, and to detect subliminal changes in barrier function and erythema. These changes, which remain undetectable in the traditional visual and palp able clinical assessment, can be used as early reactions that are followed by the development of overt skin irritation. Laser Doppler velocimetry and evaporimetry were good discriminators between irritant and non-irritant sub stances, whereas corneometry and chromametry did not clearly distinguish be tween them. Laser Doppler velocimetry and evaporimetry detected early stage s in the development of an irritant reaction before it became visible, but chromametry was not able to detect an early irritant response. It was concl uded that non-invasive measurements could improve the quality and relevance of data obtained from human irritation testing, since the data they provid e are objective, quantitative and sometimes subclinical, which also allows the concentration of a positive control to be reduced, resulting in the ind uction of less skin damage in human volunteers and reducing the ethical con cerns related to the deliberate induction of an irritant response in a 'hea lthy' volunteer. Copyright (C) 2000 S. Karger AG. Basel.