[Atopic dermatitis physiopathology].

Our understanding of the physiopathology of atopic dermatitis has much improved over the recent years. Epidermal barrier alterations are integrated into 2 theories called inside out and outside in. They are related to complex immune abnormalities. Understanding their mechanism makes it possible to foresee new therapeutics. Moreover, environmental biodiversity, the diversity of cutaneous microbiota and genetic predispositions in atopic dermatitis lead to a new, more comprehensive theory, « the biodiversity theory », integrating epigenetics.