--while skin biopsy is excellent at documenting the density and condition of the small fiber sensory nerves, it is unlikely to reveal a cause of any damage or reduced intraepidermal nerve fiber density that may be found and documented.

There are some clues that might be revealed--swelling and or "exploded from the inside" fibers might hint at an inflammatory or autoimmune process. But the samples are generally too small to collect appreciable lymphocytic infiltrates from, or to collect cytokines from (both of which might confirm an autoimmune process). And, generally, the samples are not cultured to reveal if there is a direct viral attack to the nerves (though I imagine this might be doable).

One thing that can be tested for is the presence of amyloid (my samples were--negative). This is an extraordinarily rare situation, though (literally about one in a million).

The neurologist who did the skin biopsy called me a while ago and told me that my result was normal. I felt relieved but very confused at the same time.

I asked if there are any more tests that I should do to explore other conditions. He said none and I should just continue my Gabapentin and observe my symptoms until my next appointment with him.

I am now so confused that with all the pain I have been through, and still going through, which are very typical of a PN, what condition do I possibly have? What do you think should I do next?

Thank you in advance for your help.

Is there an illness that mimic the symptoms of a Peripheral Neuropathy? I ask this question because I know the pain in my feet, stabbing pins and needles in both arms and legs, numbness in my two big toes are not just in my mind. I know that I could not wear even a pajama because just a mere touch of it causes so much pain. Having said that, what else should I do to pursue my "saga" in finding what is wrong with me.

The doctor seems to think that this is the end of the line for me, after having a negative result of the skin biopsy.

Will appreciate any suggestions/feedback.

Thank you.

--is unequivocally positive even in people with symptoms of small-fiber neuropathy.

A lot has to do with the extent of the damage, and exactly from where the samples are taken. Damage can be patchy, or the "normal" figures given for intraepidermal nerve fiber density--anything withing the fifth to ninety-fifth percentiles--may technically be designated as normal, but not be normal for you (it's almost impossible to know at what level one started before symptoms).

Do you have the report yourself, to relate to us?

Also, while skin biopsy is the gold standard for small fiber syndromes, there are some other (older) tests that are sometimes used, such as qualitative sensory testing and certain autonomic tests, such as quantitative sudomotor axon reflex testing (QSART), which measures the sweat response of small skin fibers.

There are certainly other conditions that can mimic small-fiber symptoms--circulatory dysfunction and central nervous system problems (such as central nervous system demyelinating syndromes) among them--what other testing has there been for these?

Dear Glenntaj,
Thank you so much for your reply.

The samples were taken from two spots (left leg) : 1) thigh, and 2) just above my ankle.

I dont have the report with me but I could get it from the clinic. I will post it here once I have the report.

I mentioned the QSART to my neurologist when he did the skin biopsy and his response, more or less, was: "I am not so inclined on that test. Its just a sophisticated sounding test but its not much of a help. I could diagnosed you with autonomic neuropathy if your blood pressure goes down when you get up from a lying position."

The only test that I know that may involved the central nervous system was the MRI of my head. I am not familiar with central nervous system demyelinating sydromes. I will have to google it so I can understand what you mean.

Is there a published paper about a negative skin biopsy result but manifesting the PN symptoms? I am asking so I could better discussed with my doctor. Right now, I have the impression that he is no longer giving me further tests.

THank you for your help.

I failed to mention that I also had MRI of my cervical spine and lower extremity doppler.

These are the CNS demylinating diseases that I found on the net:

Multiple Sclerosis - (according to my doctor, based on the head MRI, I dont have this.)
Optic neuritis
Devic disease (neuromyelitis optica)
Transverse myelitis
Acute disseminated encephalomyelitis
Adrenoleukodystrophy and adrenomyeloneuropathy

I dont have symptoms of any of the above conditions, except that I have dry eyes. But, I dont have Sjogren's syndrome.

Thanks again!