--that if I have eaten something with a lot of simple sugars in it (like Brian, I'm fond of ice cream), I will sometimes (not always) get an uptick in symptoms.

I've talked about this with Drs. Latov and Chin; they've said while there's not much research evidence that indicates those with non-diabetic neuropathy are necessarily affected by hikes in blood sugar, anecdotally a number of people have reported this. Dr. Chin tells me that he advises anybody with small-fiber neuropathy of unknown origin to avoid eating too much sugar AND too much gluten (whether they have tested positive for gluten sensitivity or not); he thinks both can be at least a small-fiber "irritant". (This is usually when I tease him about all the cookies and candy in those Cornell offices.)