Patients with peripheral neuropathy have symptoms involving small-diameter
nociceptive nerves and elevated thermal thresholds. Nociceptive nerves term
inate in the epidermis of the skin and are readily demonstrated with the ne
uronal marker, protein gene product 9.5 (PGP 9.5). To investigate the patho
logical characteristics of elevated thermal thresholds, we performed PGP 9.
5 immunocytochemistry on 3 mm punch skin biopsies (the forearm and the leg)
from 55 normal subjects and 35 neuropathic patients. Skin innervation was
evaluated by quantifying epidermal nerve densities. Epidermal nerve densiti
es were reduced in neuropathic patients compared to normal subjects. Epider
mal nerve densities were variably correlated with thermal thresholds. The p
roportion of neuropathic patients with reduced epidermal nerve densities wa
s larger than the proportion of neuropathic patients with elevated thermal
thresholds. These results indicated that degeneration of epidermal nerve te
rminals preceded the elevation of thermal thresholds. Skin biopsy together
with immunocytochemical demonstration of epidermal innervation offers a new
approach to evaluate small-fiber sensory neuropathy. NeuroReport 12:787-79
2 (C) 2001 Lippincott Williams & Wilkins.