I believe they are kind of permanent. In my (albeit limited) experience they can go down if the horse is out of work, but then when you work them again (or keep them in steady work) the windpuffs are there to stay.
I read on the internet somewhere that they don't have much success draining them because the tendon sheath, or wherever the windpuff forms, is stretched in that spot so even if they were to drain it it will fill back up with fluid. So I think most people leave them alone. I really don't know about treatment options honestly because I have never tried to treat them.
My Mustang is an ex-roping horse and he has them on all 4 fetlocks. But he is sound. My Foxtrotter, when I first bought her, didn't appear to have windpuffs but as soon as I started riding her steady they showed up on her hind legs. I doubt I caused them that quickly, so that's why I think they were there all along but because she was out of work they didn't show up again until she started working again.
It could be that if the injury is fresh there is still a chance of it going down. I don't know if wraps might help on a fresh windpuff? Maybe someone else would know.
PS. Thanks for the info on the "loonie." I had no idea what that was!