Atopic dermatitis pathogenesis involves directional interactions between (a) dysbiosis and barrier dysfunction, (b) barrier dysfunction and immune dysregulation, (c) dysbiosis and immune dysregulation, or (d) barrier dysfunction, dysbiosis, and immune dysregulation. For example, barrier dysfunction mediated by filaggrin deficiency promotes dysbiosis, resulting in dysregulated IL-1α production that is released upon skin injury to drive chronic skin inflammation (Archer et al 2019). NMF=natural moisturizing factors; HDP=host defense peptides.