Earlier quoted context omitted.
> Notably, a positive punch biopsy for small fiber neuropathy IS diagnosis with treatment that works fairly well. Ideopathic simply means that the base cause is unknown. What is the treatment you claim? Wikipedia claims that "Treatment [for small fiber neuropathy] is based on the underlying cause, if any." Given that idiopathic means having an unknown cause, that seems to contradict your statement.
SFN sufferer here, can confirm that there is no treatment. There are some promising research chemicals, but we are a long, long way from seeing anything available.
For severe cases, things like mexiletine can be used if you're willing to tolerate the side effects. Sodium-channel blockers like lidocaine + epinephrine can be used for localized treatment during sever pain.
It's a fuzzy distinction because SFN is almost always a sign of an underlying cause (even if unknown), and symptomatic treatment IS medical treatment.
(fwiw: I have SFN as well, not that it matters)