Anatomical and physiological basis of topical therapy of the mucosa.

The mucosa as a nonkeratinized epithelium covering body surfaces has widely differing anatomical and physiological properties depending on the organ system involved (gastrointestinal, respiratory, urinary, genital, ocular). In general, the mucosae close to the skin are more permeable to exogenous substances, more prone to irritant reactivity, and they have a unique microbial ecology which is qualitatively and quantitatively different from that of the adjacent keratinized epithelium. Clinical presentations of exogenous dermatoses in mucosae appear different from those of the skin. These specific properties of mucosae have to be considered in the development and application of topical agents, cosmetics and consumer products.