In some instances, other health conditions cause this disorder. Diabetes mellitus and impaired glucose tolerance are the most common diseases that lead to this disorder, with 6 to 50 percent of diabetics or pre-diabetics developing small fiber neuropathy. Other causes of this condition include a metabolic disorder called Fabry disease, immune disorders such as celiac disease or Sjogren syndrome, an inflammatory condition called sarcoidosis, and human immunodeficiency virus (HIV) infection.Recently several studies have suggested an association between autonomic small fiber neuropathy and postural orthostatic tachycardia syndrome. Other notable studies have shown a link between erythromelalgia, fibromyalgia, and Ehlers–Danlos Syndrome. Diagnosis
The diagnosis of small fiber neuropathy often requires ancillary testing. Nerve conduction studies and electromyography are commonly used to evaluate large myelinated sensory and motor nerve fibers, but are ineffective in diagnosing small fiber neuropathies.Quantitative sensory testing (QST) assesses small fiber function by measuring temperature and vibratory sensation. Abnormal QST results can be attributed to dysfunction in the central nervous system. Furthermore, QST is limited by a patients subjective experience of pain sensation. Electrochemical skin conductance and quantitative sudomotor axon reflex testing (QSART) measures sweating response at local body sites to evaluate the small nerve fibers that innervate sweat glands.Electrochemical skin conductance  has been evaluated for both early diagnosis of small fiber neuropathy and follow-up of treatment efficacy. Skin biopsy
A skin biopsy for the measurement of epidermal nerve fiber density is an increasingly common technique for the diagnosis of small fiber peripheral neuropathy.
Physicians can biopsy the skin with a 3-mm circular punch tool and immediately fix the specimen in 2% paraformaldehyde lysine-periodate or Zambonis fixative. Specimens are sent to a specialized laboratory for processing and analysis where the small nerve fibers are quantified by a neuropathologist to obtain a diagnostic result.This skin punch biopsy measurement technique is called intraepidermal nerve fiber density (IENFD). The following table describes the IENFD values in males and females of a 3 mm biopsy 10 cm above the lateral malleolus (above ankle outer side of leg). Any value measured below the 0.05 Quantile IENFD values per age span, is considered a reliable positive diagnosis for small fiber peripheral neuropathy. Treatment
Treatment is based on the underlying cause, if any. Where the likely underlying condition is known, treatment of this condition is indicated to reduce progression of the disease and symptoms. For cases without those conditions, there is only symptomatic treatment. See also
Neuropathy
Polyneuropathy
Wartenbergs migratory sensory neuropathy
Burning feet syndrome
Electrochemical skin conductance

References
External links

Peripheral Neuropathy Fact Sheet – NINDS
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