Pruritus represents one of the most common symptoms in dermatology and general 
medicine. Chronic pruritus severely impairs the quality of life of affected 
patients. During the last two decades a number of modulators and mediator of 
pruritus have been identified. Recently, Interleukin (IL)-31 and its receptor 
complex attracted significant interest, as clinical phase two studies 
demonstrated therapeutic efficacy of the neutralizing IL-31 receptor A (IL-31RA) 
antibody nemolizumab in patients suffering from atopic dermatitis or prurigo 
nodularis. IL-31 has also been shown to play relevant roles in allergic contact 
dermatitis, urticaria, mastocytosis, allergic rhinitis and asthma. Here, we 
summarize the current knowledge of the novel cytokine IL-31 and its receptor 
regarding cellular origin, regulation, signaling pathways and their involvement 
in biological processes such as pruritus, neuronal growth, inflammation, barrier 
dysfunction and tissue remodeling.