FLG and Alzheimer disease: In in vivo experiments, the topical application of UT protects the skin by decreasing scratching behavior, the epidermal thickness, and EI and IgE production, as well as promoting SC hydration, which, in turn, can upregulate the expression of FLG and IκBα, and downregulate MAPK and NFATc1 phosphorylation in AD-induced skin.