IL31 and Alzheimer disease: The release of T helper 2 (Th2) cytokines, such as thymic stromal lymphopoietin (TSLP), interleukin (IL)-4, IL-5, IL-13, and IL-31, contributes to skin inflammation, pruritus, neuromodulation of peripheral nerves associated with pruritus transduction, and regulation of the skin barrier in AD.