Intraepidermal nerve fiber density in patients with painful sensory neuropathy.

Despite prominent symptoms of neuropathic pain, patients with small-fiber sensory neuropathies have few objective abnormalities on clinical examination and routine electrodiagnostic studies. We quantified intraepidermal nerve fiber (IENF) density in sections of skin obtained by punch skin biopsy, and found it to be significantly reduced in patients with painful sensory neuropathies compared with age-matched control subjects. In addition, IENF density correlated with clinical estimates of neuropathy severity, as judged by the extent of clinically identifiable sensory abnormalities. IENF density at the calf was lower than that obtained from skin at more proximal sites, indicating the length dependency of small-fiber loss in these neuropathies.