I too am looking for a rhyme or reason. I have an apparently "normal" skin biopsy result in that the number of fibers fall well within the diagnostic guidelines, but I do have small and medium sized axonal swellings. Without the biopsy showing a diminished fiber count, my neuro (probably rightly so) is baffled as to the body-wide intense burning and paresthesias I experience. From what I've read, doesn't involvement of the DRG have to demonstrate itself in at least a positive finding via biopsy, nerve conduction study or a deficit clinically of some kind? This thread is a little old, so I don't know if "Idiopathic PN" is still monitoring or if you have had any success yet in finding your "reason." I hope so.

--I think you are showing some evidence of nerve damage--those axonal swellings. Large scale axonal swellings are not typical and imply some sort of immune attack, with lymphocyctic inflitration of the nerve tissue.

Also, while you may fall well within the guideline for "normal" nerve fiber density, that number is only a snapshot in time and doesn't tell us where you were before symptoms hit, and whether you would have had a higher/lower number then--I've written often on how the McArthur protocols rather arbitrarily define normal intraepidermal nerve fiber density as below the fifth percentile or above the ninety-fifth percentile for age-matched "normals", and how even if you get a "normal" finding, of being, say, in the twenty-fifth percentile we would not know if three years ago you would have been at the fiftieth percentile.

It is good, though, that skin biopsies are repeatable--often it is the tracking of percentiles and nerve fiber condition over time that allows for more of an interpretation as to progression or healing. Mine have gone from the second to the eighteenth percentile over time--so I am now technically "normal", but it is more important to note that I have gotten some re-enervation over the years.

I really am fascinated... a bit excited... about what you write about lymphocyctic infiltration or immune attack on nerve tissue because maybe it's closer to an answer. I have had a persistent skin manifestation of the virus I had over two years ago called levido reticularis and the biopsy of that (not the skin punch biopsy for the nerve fiber density) showed a chronic inflammatory perivascular infiltrate. All testing for vasculitis is negative though and the area of the nerve punch biopsy did NOT show any inflammatory infiltrate. So, conflicting results within a close time frame. I really am lost as to why my neurologist hasn't honed in on this. And, even if he did, I haven't been lead to believe there's anything available to me but symptomatic treatment (Gabapentin). It worries me that I have a progressive inflammatory condition that is not being addressed and it will eventually result in irreversible damage. Really, so many thanks for sharing all your knowledge with us via Neurotalk.

I have to ask this.... As I had a terrible skin problem
that was finally diagnosed as drug induced lupus.

The culprit was lisinopril an ACE inhibitor for blood pressure.
All that family is implicated in this reaction. I had been on
it for 10 yrs.

If you Google "drug induced lupus" you will find at the
lupus organization a long explanation about this and
a list of drugs so far identified (but it is incomplete) for
some. PubMed searches will be better. That is where I
found my data for myself. Use generic name + lupus
in the keyword search there.

Livido reticularis is an autoimmune sign. Drug induced
Lupus does not raise ANA levels so doesn't show up
in that testing.

Heb1212,

I haven't found that elusive rhyme and reason... yet. In fact, the pain has slowly gotten worse. The last time I saw my neuro, I was given a food supplement called Metanx. He sounded positive on the effectiveness. For someone who doesn't lose hope in getting better, I was optimistic. I only had 2 days of "feel better" after taking it. After 2 days, it came back to the "normal" pain.

Mary

Mary... gosh, so very sorry. Mine too has gotten worse over the two years since onset, which so discourages me because I worry constantly about the progressive nature. When will it level off? I'm trying my hardest to adjust to my new "normal" too. I wish you God's comfort