NGF and Alzheimer disease: Indeed, TRPA1 activation by oxazolone induced chronic dermatitis in mouse ears and concomitant up-regulation of inflammatory cytokines (i.e., IL-1β, IL-4, and IL-16 and chemokine (C-X-C motif) ligand 2 (CXCL-2)), neuropeptides (i.e., SP and endothelin (ET-1)), nerve growth factor (NGF), and neurotransmitters (i.e., serotonin) known to induce AD, pruritus, and pain and increase nerve fiber density (Liu et al., 2013).