I can go on forever on the epidermal nerve fiber density biopsy, or 'skin' biopsy, which is not really a biopsy of skin as much as a piece of skin from which they determine the density of small nerve fibers. I utterly agree with Glenntaj.

It is confirmatory, in that it is never wrong. If you have abnormal results, they are indicative of small fiber neuropathy.

I don't like doctors taking potshots at diseases when the technology exists to do a solid, quantifiable diagnosis. PN or peripheral neuropathy has many manifestations. My feet did not burn one iota. My calf biopsy has less than 2fibers per mm. 7 is normal. My feet have 2.5 fibers/mm. The thigh is normal but showed sweat gland innervation was reduced. The fore arm was normal number of fibers but showed that the pattern of innervation was not normal, and the sweat glands were not innervated normally. My biopsy is 3 years old this month, and I am sure if one was done today, it would be the same or worse.

If I had not had this done, I would not have the 'diagnosis'. The numbness and tingling could have been MS....or some other disease, who knows. That said, small fiber neuropathy is akin to knowing you have a fever. What is causing that fever is a totally different issue. Now that I know I have small fiber neuropathy, other testing showed it is also autonomic, which means, for example....I don't sweat to heat. That is a critical thing to know. I also learned a lot from my tilt table test...and other testing for causes, which turned out negative. Other tests will likely be done.

Lastly, is the issue of causation, which takes a long time and tremendous work to figure out. Some causes are on the cusp of discovery of by some of the brightest minds out there....just reading their work makes me humble. I can't believe people come in that 'variety' of smart. It is like Steven Hawking smart, but in molecular biology and genetics.

I prefer to know if a disease is curable or not, treatable versus curable. Symptoms of PN can be treated with varying degrees of success depending on each and every individual's personal case. Treating the cause of your neuropathy may cure your neuropathy. Without knowing a cause, you can only treat symptoms.

There is no generalizing symptoms, causes, or treatment of the mystery of PN. The best we can do is share what we know, admit what we do not know, and support whatever choices that we all make as individuals.

High quality nerve fiber density studies are done, as Glenntaj said, at tertiary or what are known as research centers. I would love to see an idiopathic PNers who want to find a cause, get care at those centers. If you know a cause for your PN, it is less critical, as you can likely get treatment for the cause at a specialty clinic for your disease with consult to neuro. (Such as people with rheumatologlical disease and neuropathy who see both specialties, or diabetics or endocrinological disorders who also see neuros.)

Some people prefer not to keep searching for the cause of idiopathic PN, and that is fine too. There is an end to the internet, at least right now.