The epidermis is a living, multilayered barrier with five functional levels, including a physical, a chemical, a microbial, a neuronal, and an immune level. Altogether, this complex organ contributes to protect the host from external aggression and to preserve its integrity. In this review, we focused on the different functional aspects.
Keywords: ceramides; desmosomes; epidermis; immunity; keratinization; microbiome; sensory nerves; skin barrier; stratum corneum; tight junctions.