I had the gran'daddy of nasal polyp collections up until eight years ago.
I'm not sure what brought them on, but for years I smoked like a battleship. You always knew when I was approaching because of the plume of smoke before I appeared over the horizon. This started giving me occasional problems with singing (a couple of bad bouts with acute laryngitis), and I finally quit smoking in 1978.
But at the time, I was working in a closed office building in which almost everybody recycled each other's colds or other plagues. The building was later declared "sick" and the air conditioning system had to be thoroughly decontaminated of bacterial deposits, mold spores, and other things too fierce to mention. I never had allergies until I worked in that building, and since then, I've had fairly constant rhinitis (manifests itself in post-nasal drip and constantly having to cough or clear my throat). I seem to be allergic to this planet's atmosphere.
My nose was almost constantly plugged up. I became, literally, a mouth-breather. Finally, one day when my wife and I were out in the car, my nose was so plugged and my mouth was so dry from breathing through it that I felt like I couldn't breathe at all. I had a panic attack. Barbara drove me to the emergency room of a nearby hospital. The doctor peered up my bugle and told me that it was no wonder I couldn't breathe; my nasal passages were wall-to-wall polyps. He referred me to a specialist (an otorhinolaryngologist) at the Northwest Nasal Sinus Center in north Seattle (how's that for alliteration?). A couple of weeks later, the specialist operated (I was out at the time). Endoscopy, no external incisions. When I woke up in the recovery room, I was told that they had never seen a set of sinuses so thorough stuffed with polyps. I was quite probably some kind of record. But even though I was packed here and there with wads of cotton, I could breathe! Through my nose! There were several follow-up visits, prescription nasal sprays, rinsing my sinuses out with saline solutions by the pint a couple of times a day (now that's a million giggles! He had me using a Water-Pik with a special snoot attachment). And in the final exam many months later, he declared me polyp-free. The operation was in November of 1995. Since then, my regular quack looks up my schnozzle with each exam, and so far, so good. No recurrence. And I can breathe freely.
But apparently I still have rhinitis or something like it. The occasional monumental sneezing fit (allergies, I presume—I'm especially allergic to the ink in the TV Guide), I still have to cough or clear my throat often, and sometimes my nose will start to run at the damnedest times (buy stock in Kleenex).