I've written about this in numerous other places--
 

--but here's the short version.

When the norms for intraepidermal skin density number were established, after a lot of normal and symptomatic individuals were tested (mostly at Johns Hopkins), the researchers there decided--rather arbitrarily, from my view--to set the fifth and ninety-fifth percentiles as "abnormal" and indicative of small fiber neuropathy. (There is a lot of precedent for picking those numbers in medical research, though, that has a lot to do with normal--bell curves shaped--statistical distributions.)

There was a very high standard deviation noted in the research samples, though--that is, the absolute range of number of fibers per cubic centimeter of skin was quite broad. So a large range of numbers would be considered "normal". There was a tendency noted for absolute numbers to decrease with age.

The problem is that since most normal, asymptomatic people don't have skin biopsies done, we don't know what number they start at. A person could be symptomatic, have a skin biopsy performed, show up at the twentieth percentile and be told "no neuropathy". Problem is we don't know if that person was ALWAYS around that level--it's possible s/he could have once been at the fiftieth percentile, say, and if that had been known this biopsy figure would represent a diminishing of fiber density.

This is why the condition of the fibers is supposed to be examined as well. As enbloc notes, fiber swelling, along with excessive branching, may be noticed in some asymptomatic people with no symptoms, but it is not a "normal" finding and usually would prompt some more investigation or at least monitoring. Fortunately, skin biopsy is non-invasive and repeatable, so one can have these done serially (I have) and compared for further diminishing of density or deterioration of condition--or, hopefully, for improvement of density and condition. (This is how we were able to clinically document that my acute-onset body-wide small-fiber syndrome, whatever it was, was healing slowly over time--though no one knows if I will ever get back to whatever my original nerve fiber density numbers were, as we don't know these. But I have gone from the third and fifth percentiles to the sixteenth and twentieth percentiles and the nerve fibers are much less swollen and branched than they were during my first skin biopsy.)

Dreamer,

Let me back-track to your last reply.

Of course, no one 'wants' to go to doctors, but you have several things going on that NEEDS to be properly evaluated by specialists. Your neuro isn't going to Dx a likely autoimmune disease for you. You have tell-tale signs of one with the joint pain and swelling, then add rapid onset neuropathy and autonomic dysfunction!! You NEED a rheumy to piece together whether an AI disease is responsible...which it sounds like it is. BTW, up to 40% of those with autoimmune disease (myself included) are what they call sero-negative, meaning negative blood tests. They still have the condition, it just has to be proven in different ways (biopsies, US, MRI, etc).

Do you have other symptoms...like fatigue, dry mouth/eyes, rashes (face or anywhere else), low grade fevers, etc? What are your autonomic symptoms and what testing have you had for them?

Your joint swelling/pain can actully help you get a Dx AND appropriate treatment for your neuropathy. They may be able to confirm an inflammatory arthritis by US of the joints looking for fluid and/or joint fluid test. If they can confirm autoimmune process this way, then your neuropathy is likely a result of the AI disease and treatment with IVIG or steroids would be approprate and likely helpful for you.

By all means, you should have the skin biopsy repeated in 6 months for re-evaluation...based upon what Glenn reported and I mentioned earlier. This, with your obvious rheumatological condition, would help determine the exact cause of your neuropathy and what treatment would be best.

Hope this is helpful.

Thank you for taking the time to explain this to me!

Thank you. No dry eyes or mouth, but for about eight weeks, a few months ago, I had a low-grade fever...well, it would flux from 99-101.3. My doctor ran a bunch of bloods and she couldn't find a reason for it. So she wanted me to see a rheum. but since I knew I'd see this neuro, I wanted to wait to see him first since I had been waiting literally years to see him. After about 8 weeks, my fever was fine! But the past month or so, it's back and I'm again feeling awful all of the time--tired, etc. because it wears me out a bit, esp combined with my back pain/feet pain. I really expected the biopsy to say something because this burning has been going on for years, and I was surprised it was negative, but I'll hopefully talk to the neuro soon. I left another message this morning and the lady said that the doctors sometimes take a long time to do call backs.

Thank you so much:)

You really need to consider the rheumy...in conjunction with seeing the neuro. They need (and will in most cases) to work together when it is an autoimmune process causing the neuropathy.

Do you know what labs have been done? Have they done CRP and ESR? I ask because both of these are markers for inflammation. It is possible that your axonal swellings could be from inflammation, as well as your joints, and even your low grade fevers. If it is, then a short course of steroids might help with multiple things...including the burning.

When you talk to the neuro, ask him/her for suggestion for a rheumy...they have a way of working better with other specialists that THEY recommend.

Are you being treated for your autonomic problems? In many cases they require yet another specialist (cardio) if you have BP and heart rate problems? What autonomic symptoms do you have? The low grade fevers can also be from autonomic...as temperature regulation is an autonomic function.

All these things are tied together and when you figure out which AI is root cause, then treatment options will be clear and you will finally get some relief.