Morphological features of nerves in skin biopsies.

Skin biopsy is an effective test for diagnosis of peripheral nerve disorders. The most commonly reported indication of abnormality in a skin biopsy is reduction of epidermal nerve density. Morphological changes of epidermal nerves and the underlying subepidermal nerve plexus provide added evidence for the presence of neuropathy. We determined the prevalence of epidermal axon swellings, dermal axon swellings, and a unique type of epidermal nerve that we call a crawler, in a group of normal subjects, diabetic subjects, and patients with idiopathic small fiber neuropathy. Other morphologic features examined include thinning of the subepidermal nerve plexus, sprouts at nerve terminals, encapsulated endings, and immunoreactive basal cells.