My heart goes out to you. But there is little that I or anyone else can say.

There must surely be others who know or are pretty sure that they know the cause of their PN. But does that really help.

Those that have no cause, have perhaps a hope that it will get better. But the pain of that hope dangling just outside your reach, is different but surely just as cruel as the knowledge that it won't improve. At least you have certainty. Not much of a positive, but something.

I wish that there was more that I could say or do.