It could be a chronic inflammation. I don't know why urologists think they can treat inflammations with antibiotics, but that seems to be their first line of treatment to help to create more serum resistant microorganism!
I tried to explain to mine the dynamics of a bacterial infection, but he still wanted to give antibiotics a try, and of course it was a waste of money and time!
In case of a chronic inflammation, only the big clipper will help, and if you diagnosed with it, your health insurance should pay for the cost.
Talk with him about inflammation and not infection, and see what he says!
Good luck!