Intraepidermal nerve fibre density at wrist level in diabetic and non-diabetic patients.

Myelinated nerve fibre pathology has been demonstrated at wrist level in diabetic patients. We examined if quantification of intra-epidermal nerve fibre density (IENFD) in hairy and glabrous skin at wrist level could detect signs of subclinical small nerve fibre neuropathy. In 35 diabetic patients who were age and gender matched with 31 non-diabetic patients, punch biopsies were obtained in conjunction with surgical carpal tunnel release. Biopsies were immunostained with anti-protein gene product (PGP) 9.5. The IENFD was quantified using manual counting by light microscopy. We could not demonstrate significant differences in IENFD between diabetic or non-diabetic patients. Additionally, no differences were found between patients with Type 1 and Type 2 diabetes or in diabetic patients with and without neurophysiologic signs of mild peripheral neuropathy. However, the IENFD was significantly higher in hairy skin compared with glabrous skin. Furthermore, the IENFD was significantly higher in females than in males and correlated with age, but not with duration of diabetes or glycated haemoglobin (HbA(1c)). In mild neuropathy no difference in IENFD at the wrist level could be detected between diabetic and non-diabetic patients. Independent of diabetes, we found IENFD to be higher in hairy skin compared with glabrous skin and higher in females than in males. These results must be taken into consideration when assessing small nerve fibre pathology in the upper extremity.