IL31 and Pruritus: PO reduces the release of Tnf-α from macrophages, Il-4, Il-31, and Tslp from the Th2 axis, and Ifn-γ from the Th1 axis, regulates the balance of immune cells, reduces the number of mast cells, lymphocytes, monocytes, neutrophils, eosinophils and basophils, reduces the secretion of His and Ig E, and thus alleviates allergic reactions, skin nerve fiber density and pruritus (38).