The drip gets better when I don't have chocolate or coffee. That is really strange but I think those two things have a negative impact on sinuses (at least mine). I love both of those things, but the instant I have one or the other I get an itchy nose then the mucous starts. Wine also inflames my sinuses and increases the drip. Eating eggs, which I do infrequently, gets the mucous going just like dairy. Stress does it too; sometimes if I start concentrating on the post-nasal drip, it'll seem to start getting worse immediately. I've done the allergy medications. They don't impact the post-nasal drip. As I said before, I don't suffer from the typical allergy symptoms. The problem seems very local--right at the back of the sinuses. I can slow up the drip considerable if I am quiet and relaxed. But how often is that possible?
I'm going to try the dairy-free thing for two months--which is the amount of time they say to do it on allergy web sites (like Dr. Weil). Hopefully there'll be some improvement with bad breath.
I live in a big city. I'm sure the polluted air doesn't help much either.