Hi I also have unexplained PN and have had basically every test in the book and seen so many specialists. I also have to deal with doctors guessing what may or may not be going on. I have found for myself many specialists don't make connections between symptoms that are going on. They don't like to look outside of their speciality. I am not saying this is all docs but some. What type of specialist are you seeing? Have you went for another opinion?
Though it may not cure you have you tried to make changes to your diet? Even if a person is not allergic some foods can cause a flare more then others. I am wondering if it would help some of your symptoms such as psorasis
My doctors too have also said so many things are a fluke of problems that have happened along with the severe limb pain from my RSD and PN but at 28 when I developed this I dont think so. Like you I developed severe skin problems,eye,ear problems etc. I dont buy it that it is a fluke.
Unfortunatly at the moment since I am diagnosticly tested out the course I have had to take is about pain control which is hard of course when something more underlying could have been a cause. Have you worked with a pain doctor? Many don't just deal with meds but other treatments such as diet,exercise,different forms of mind and body therapy.
Hope you get some answers and feel better