TL;DR I was able to succesfully use Uva Ursi and Antibiotics by combing them with an antihistamine (Uva Ursi and the antibiotics previously caused severe burning sensation of my skin.)
Trimethoprin and Doxycycline were not having a direct toxic effect on my nerves, but were causing mast cells to further irritate and lead to a viscious inflammatory cylcle and causing severe burning pain.
This was alleivated by the antihistamine by about 70-80%. It wasn't able to block the reaction, but it made them 'tolerable' instead of being completely intolerable to take.
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I had a chronic prostate infection from September 2022 last year and was unable to tolerate Trimethoprim and Doxycycline. Every time I would try to take these antibiotics (I made multiple attempts) I would get an massive increase in burning pain all over my skin. It was intolerable and forced to to stop within 3-4 days. I had taken these antibiotics years ago without any issues whatsoever, so this was weird, and no one could figure it out.
I also had the exact same reaction to Uva Ursi supplement. It increased burning all over my body.
Within days of stopping the antibiotics or urva ursi, the burning would be about 90% better. I had very minor symptoms after months of B12 supplements.
Months later I developed a chronic bladder infection but I was able to figure out a combination of supplements to resolve this (Cysticlean (standardized cranberry supplement with high PACs)), Yeast Beta Glucan, Life Extension AlpoLactoferrin, and Oil of Oregano (not sure this last one did anything but took it anyway). Also, while I had the chronic infection of the bladder, it did temporarily increase my burning skin sensations. So there was some kind of immune system component clearly.
Here's how I figured it out
Raoultella (the bacteria I have) is a histamine producing bacteria and when treated (case studies) the doctors use a antihistamine due to significant complications due to this feature of the bacteria. Perhaps when the bacteria is stressed by the antibiotic, it produces greater amounts of histamine? These infections are usually treated with antihistamines + antibiotics due reduce skin adverse reactions.
In one study, it's shown that irritated or sensitized nerves in the skin (neuropathic skin) respond to histamine not presenting with an itch, but it's converted to burning sensations or pain. A quote from the abstract:
"Conversely, histamine application in neuropathic skin induced severe increase in spontaneous burning pain but no itch."
pubmed.ncbi.nlm.nih.gov/117...
3. It's possible that histamine levels could be increasing when I take the antibiotics, and I might be sensitized to them. I remember when I used to take Trimethoprim, I'd get an itch for a few days when starting (it's common) but then it would go away as I carried on.
I also had an experience years ago when I developed SFN from Cipro, and I would react weirdly to things such as methyl parabens that were in liquid formulations of antibiotics with severe burning (formulations of Trimethoprim without the methyl paraben would not cause issues). This reaction would not occur years later when my nerves were healed (this was back in 2008).
I believe that when C nerve fibers are damaged, excess histmaine produced by even minor hypersensitivity reactions would lead to a cascading inflammatory reaction until the cause is removed. This minor hypersensitivity may not even cause issues in otherwise normal healthy skin/nerves but be transient.
I started taking loratadine - antihistamine
First, this helped the remining burning sensations that I would get.
Secondly, when I began trying uva ursi again, I started dosing it slowly, so I began with 1/40 of the dose, and rapidly over 3 days started taking the full 40 drops (2 ml) per day.
I combined it withi the antihistamine, which I took hours before my uva ursi dose.
While the antihistamine has not completely eliminated the reaction with my nerves, it's about 70-80% less severe and less frequent during the day.
I did the same for Trimethoprim and it worked.
The cause (in my case) of my flare up of neuropathy was due to histamine. It was not enough to cause an overt and visible reaction in the skin, but due to very sensitive C nerve fibers, it was enough to cause a cascading inflammatory reaction that would lead to severe and non-stop burning sensations. This is mostly blocked by the antihistamine.
Anyway, I hope that helps someone! 
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