International guidelines for the in vivo assessment of skin properties in non-clinical settings: part 1. pH

Background: Skin surface pH is known to influence the dissolution and partitioning of chemicals and may influence exposures that lead to skin diseases. Non-clinical environ-ments (e.g. workplaces) are highly variable, thereby presenting unique measurement challenges that are not typically encoun-tered in clinical settings. Hence, guidelines are needed for con-sistent measurement of skin surface pH in environments that are difficult to control. Methods: An expert workshop was convened at the 5th Inter-national Conference on Occupational and Environmental Expo-sure of Skin to Chemicals to review available data on factors that could influence the determination of skin surface pH in non-clinical settings with emphasis on the workplace as a worst case scenario. Results: The key elements of the guidelines are: (i) minimize