Figure 1.

A graphical representation of the interactions between the epidermal barrier, microbiota, and the immune system. In healthy individuals, the epidermis constitutes a barrier preventing the uncontrolled proliferation of potentially harmful microorganisms. A diverse array of microbes participates in the crosstalk with the immune system and ensures its maturation to maintain immune balance within the skin. In AD, the epidermal barrier defect and dysregulation of innate and acquired immunity result in the enhanced adhesion and proliferation of some bacterial species, especially staphylococci. Microbial dysbiosis subsequently aggravates the skin defect by degrading the components of the epidermal barrier and potentiating Th2-skewing.