IL31 and mastocytosis: They demonstrated that mast cells are the main source of IL-31 in mastocytosis in both the skin and bone marrow, while another study correlated itch intensity and sera levels of this cytokine [80], although some other factors could be involved in the pruritus, such as histamine or a possible keratinocyte-derived mediator, which subsequently activates unmyelinated-itch fibers [88].