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.