Autonomic neuropathy in the skin: a histological study of the sympathetic nerve fibres in diabetic anhidrosis.

In diabetics with the anhidrotic syndrome, autonomic nerve fibres were studied in skin biopsies using argentic techniques and light microscopy. The Minor test was used to differentiate normal from anhidrotic skin areas. In the anhidrotic areas, histology of the nerve fibres showed beading, spindle-shaped thickening and fragmentation adjacent to the sweat glands. These changes were similar to those observed in two patients who had previously undergone lumbar sympathectomy. No abnormalities of the sympathetic nerve endings could be found in biopsies taken from normal areas of the forearm of the same patients. We conclude that the diabetic anhidrotic syndrome, a form of diabetic autonomic neuropathy, is due to a lesion of the sympathetic nerve supply to the skin. It is suggested that the Minor test or a skin biopsy should be performed in diabetic patients who are being considered for surgical sympathectomy.