Small fiber neuropathy involves the thin nerve fibers that carry pain and temperature sensation, and that regulate autonomic functions like sweating, blood pressure response, and digestion.
Symptoms
Burning, particularly in the feet and often worse at night. Stabbing or electric sensations. Skin that is painfully sensitive to light touch. Temperature sensations that don’t match the environment. Some people describe it as walking on gravel or having sunburned feet.
Because small fibers also serve autonomic functions, some people additionally notice changes in sweating, lightheadedness on standing, or digestive irregularity.
Recognized contributors
Glucose dysregulation, including prediabetes, is among the most common. Autoimmune conditions including Sjögren’s and celiac. B12 and other nutritional factors. Thyroid dysfunction. Certain infections. Chemotherapy exposure. Some medications. Genetic causes in a minority of cases. And a meaningful percentage where no cause is identified even after thorough evaluation.
Its overlap with other conditions
Small fiber neuropathy travels with dysautonomia, POTS, mast cell activation, hypermobile Ehlers-Danlos syndrome, and post-viral illness including long COVID. People with these diagnoses frequently have small fiber involvement, and people presenting with small fiber symptoms frequently turn out to have one of these conditions.
This is a population we see routinely, and the overlap is a reason evaluations here tend to look wider than the feet.
How it is evaluated
Clinical history and sensory examination, followed by a search for contributors. The pattern establishes what is happening. The workup establishes why.
Free 15-minute phone consultation.
FAQ
Is small fiber neuropathy serious?
It is rarely dangerous in itself but can be significantly disabling, and it sometimes signals an underlying condition worth identifying.
Can small fiber neuropathy improve?
It depends on the cause and duration. Where an active contributor is identified and addressed, improvement is possible. Where nerve loss is long-standing, expectations should be set accordingly.
Reviewed by Alvin Philipose, DC, ICCP. This page is for informational purposes only and does not constitute medical advice. Individual results vary and no outcome is guaranteed. If you are experiencing sudden weakness, difficulty breathing or swallowing, new bowel or bladder changes, or a wound or infection on your foot, seek emergency care.