My guess (un-educated) is that you've probably had POIS for many tears, but they've treated you for everything else because nobody knows what POIS is.
As I said, I had a vasectomy reversal, after 20 yrs of vasectomy. My POIS effects all the "ducting" from the gonads up to the seminal vessels. Everything swells down there including my prostate for the days of POIS.... at least before I discovered niacin.
Then in about 10 days, everything returns to normal. (If I make it that long without sex.)
So you say you "leak", without any sexual arousal, and that alone causes POIS?
Inasmuch as I reject the desensitization theory, we can't have allergy to our own semen, I believe we can "react to it", but more as an autoimmune reaction than an allergic reaction.
This would explain at least the cases like ours where there may have been some injury or plumbing problems that permits sperm to "go where it shouldn't".
And although the end result may be the same (in terms of symptoms), the solution and process is not at all the same.