Small Fiber Neuropathy in Fibromyalgia and CFS

Nerve cells
Pasieka / Getty Images

Is the pain we feel with fibromyalgia and chronic fatigue syndrome from a type of nerve damage called neuropathy? It's an idea that's been around for several years—after all, our pain is very similar—but is garnering wider support as researchers find more evidence.

Research first presented at the American Academy of Neurology's 2010 annual meeting in Toronto suggests that many of us with these conditions have something called small fiber neuropathy—abnormalities in the small nerve fibers, which are near the surface of your skin a deal with pain and temperature sensation.

(Temperature sensitivity is an extremely common symptom of fibromyalgia and chronic fatigue syndrome.)

In this study, the researchers took skin biopsies from 30 people who had either fibromyalgia, chronic fatigue syndrome, chronic pain syndrome, or a combination of these illnesses, as well as from a control group. Of the people with the painful conditions, biopsies showed that 13 of them, or 43%, had evidence of small fiber neuropathy.

(That's a large percentage, certainly, but given the small sample size of just 30 people, it's not conclusive. It is, however, promising enough to lead to larger studies in the future.)

Dr. Devanshi Gupta, the lead researcher, says doctors should check for small fiber neuropathy via skin biopsies in patients who have the following symptoms:

  • Sharp, shooting pains,
  • Orthostatic hypotension,
  • Autonomic symptoms,
  • Skin changes related to interrupted nerve supply,
  • Incontinence,
  • Sexual dysfunction,
  • Or other neuropathic symptoms.

However, some doctors say that skin biopsies aren't reliable enough alone and should only be used to confirm a diagnosis based on examination and history.

You'll likely recognize several of the symptoms listed above as fibromyalgia and chronic fatigue syndrome symptoms, including the pains, orthostatic hypotension (blood pressure drop upon standing that makes you dizzy), and autonomic symptoms.

The overlap of symptoms can make it harder to diagnose small fiber neuropathy based on symptoms and an exam alone, so the biopsy may be more useful for confirming the diagnosis in us than in the general population.


More evidence is mounting to support the theory that these conditions, or at least a large subgroup of them, are neuropathic. The prevalence of intense nerve pain, strange nerve sensations, and abnormal nerve response all point that direction, as does the fact that many of us are helped by treatments aimed at neuropathy, such as Lyrica (pregabalin) and Neurontin (gabapentin). Checking for small fiber neuropathy may help doctors determine which of us are likely to respond to these kinds of treatments.

So if this research is accurate and just under half of us have this type of neuropathy, what does that mean for the rest of us? That's something that'll need to be explored further, but that exploration will be much simpler if they can exclude the subgroup with small fiber neuropathy. We know we're not all alike, and the more we can be accurately subgrouped, the sooner we'll be able to find real answers to our many questions.


Gupta D, Harney J. Small fiber neuropathy demonstrated in pain syndromes. Poster session presented at Annual Meeting of the American Academy of Neurology; 2010 Apr 10-17; Toronto, Ontario.