Figure 4 Diagnosing neuropathic pain Adapted with permission from Truini, A., Garcia‑Larrea, L. & Cruccu, G. Reappraising neuropathic pain in humans — how symptoms help disclose mechanisms. Nat. Rev. Neurol. 9, 572–582 (2013), Macmillan Publishers Limited. The corneal innervation image in part b (left panel) is reproduced with permission from Tavakoli, M. et al. Corneal confocal microscopy: a novel noninvasive test to diagnose and stratify the severity of human diabetic neuropathy. Exp. Neurol. 223, 245–250 (2010), Elsevier Colloca, L. et al. (2017) Neuropathic pain Nat. Rev. Dis. Primers doi:10.1038/nrdp.2017.2