Innate immunity in atopic dermatitis.

One of the most important functions of the skin is to provide protection from infectious pathogens. This is achieved by two complex and complementary powerful strategies, namely by preventing pathogen invasion and by raising innate and/or adaptive immune responses following infection. Most pathogens cannot penetrate healthy skin, and the vast majority of skin infections, thus, results from breaches of cutaneous integrity (skin wounds, arthropod bites, barrier function defects). Cutaneous infections, in turn, are controlled primarily by a functioning skin innate immune system and efficient host defence responses. Patients with atopic dermatitis (AD) exhibit both, impaired skin barrier function and defects in skin innate immunity. As a result, AD patients frequently develop skin infections which contribute to the pathogenesis and the course of their chronic inflammatory skin condition. Here, we discuss how skin innate immunity works in healthy individuals and how skin innate immunity is impaired in patients with AD.