About 10 years ago, I attempted to explain some of the features of pH measurements on the skin's surface. At that time, common knowledge accepted that alkaline substances, (soaps), applied to the skin might elicit adverse skin effects and that skin cleansing with neutral surfactants might be preferable. Questions about this simplistic concept, pH dependence of skin irritation, are documented in the literature.
The picture was further obscured by the classical attribution of the merits to the skin's so-called acid mantle. Since that time, investigators in skin physiology have avoided the controversy of potential skin damage by exposure to mildly alkaline substance. The most recent studies reported here describe newly discovered phenomena involved in pH changes during terminal differentiation, therefore, the earlier veiw is in need of updating.