I just came across this. My husband Mark was just diagnosed with small fiber neuropathy and has the tingling from just above the knees to his toes, getting worse but no pain. Just wanted to add that although his dr is still trying to find a separate cause for the sfn, it all started at the same time as some other issues that were diagnosed as side effects of MGUS (a rare blood disorder that in a small number can lead multiple myeloma). Another type is MGNS, which is nerve based and probably what Mark has. His other issues are lightheadedness, fatigue, anemia, and no ability to fight viruses. A uti put him in the hospital with a raging fever. It's just something you can easily get tested for with a blood draw. It's just so rare (and mostly black men, but my husband is white) that many professionals haven't even heard of it. I really hope you've found or find a cause and can start to feel better.