[Usefulness of skin biopsy in the diagnosis of small fiber neuropathy].

Diagnosis of small fiber neuropathy may be challenging due to subtle clinical signs and to the normality of nerve conduction studies. Skin biopsy is a non invasive method which allows to quantify intraepidermal nerve fiber density after a simple immunostaining. The values measured must ideally be compared to normative data obtained on control subjects in order to determine their significance. When the diagnosis of small fiber neuropathy has been made by means of skin biopsy, possibly combined with laser evoked potentials, a diagnostic work up has to be done in order to find one of the classical causes of this disorder. To date, skin biopsy is useful to confirm the diagnosis of small fiber neuropathy but lacks utility to find its etiology.