Overview of the different receptor types of primary afferent sensory neurons, as well as cascades, during itching. IL-4R, interleukin-4 receptor subunit a; IL-31R, interleukin-31 receptor; NK-1R, neurokinine-1 receptor; TSLPR, thymic stromal lymphopoietin receptor; TRPV1, transient receptor potential cation channel subfamily V member 1.