Small fiber peripheral neuropathy

Small fiber peripheral neuropathy (SFSN/SFN) is a type of peripheral neuropathy that occurs from damage to the small unmyelinated  peripheral nerve (any nerve of the nervous system outside the central nervous system) fibers.

It is common in Ehlers-Danlos syndrome (EDS), fibromyalgia,  and postural orthostatic tachycardia syndrome (POTS). Many other conditions can also cause small fiber peripheral neuropathy such as celiac disease, rheumatoid arthritis (RA), lyme disease, vitamin B12 deficiency, and more.

Symptoms

 * autonomic symptoms (Includes many symptoms listed below.)
 * burning, tingling, prickling (paresthesia)
 * constipation
 * dizziness
 * dry eyes
 * dry mouth
 * incontinence
 * loss of sensation
 * numbness
 * orthostatic hypotension,
 * sexual dysfunction
 * sharp, shooting pains
 * skin changes related to interrupted nerve supply (skin discoloration)
 * sweating
 * temperature sensitivity
 * or other neuropathic symptoms.

Diagnosis
An examination and detailed review of the symptoms, the rate of progression, and complaints suggestive of autonomic fiber involvement are necessary for diagnosis. Quantitative sensory testing (QST), quantitative sudomotor axon reflex testing (QSART), skin biopsy, and electromyography and nerve-conduction studies are useful.

The Utah Early Neuropathy Scale (UENS) was developed to help diagnosis SFN. The Neuropathic Pain Symptom Inventory (NPSI) can also help.

Treatment
Gabapentin, pregabalin, amitriptyline, nortriptyline, 5% lidocaine patch, tramadol, and opioid analgesics are used to treat SFN.