Small fibre neuropathy is a disorder that predominantly affects the function of the small nerve fibres. The small nerve fibres are the nerve terminals, located under the skin surface, that are responsible for pain and temperature sensation. Besides these, there are small nerve fibres that form a connection between the brain and several organs. These small nerve fibres are responsible for autonomic functions; functions such as regulation of blood pressure, gastrointestinal functions and perspiration that take place involuntarily, without conscious thinking.

Small fibre neuropathy is a form of polyneuropathy. The word ‘poly’ originates from Greek and means “many”. Neuropathy originates from the Latin word for “nerve disorder”. Thus, polyneuropathy is a disorder in which a considerable number of nerves malfunction. Though small fibre neuropathy is a form of polyneuropathy, the term ‘polyneuropathy’ usually is used for dysfunction of the large nerve fibres.