In addition to these mediators, proteases (e.g., kallikreins, tryptase, endogenous/exogenous proteases) [89,90], neuropeptides (e.g., substance P) [91,92], and neurotrophic factors (nerve growth factor (NGF), artemin) [82,83,93] are considered to contribute to pruritus. Here, NGF is linked to Pruritus.