I have allergies that hit me hard in the late summer, early fall. Over the years, I noticed a pattern that if I caught a cold around Labor Day that it would linger all the way to Thanksgiving. I've pretty much attributed it to the allergies weakening my immune system and my body not being able to recover from hunting in the cold so much.
One year, 1997, I had a cough the whole fall season. Its no coincidence, its the only season that I've failed to get a buck since 1994. Most nights I either wouldn't even go out or wouldn't go to my best spots simply because I couldn't go 30 minutes without coughing. Of course, one cough near a bedding area...and you can pretty much forget seeing a big buck that outing.
Anyway, here's what I do. First, I take better care of myself this time of year..eat better, etc. Second, there's two products that help slow a cold down before it gets started. Zicam - a nasal gel, and Cold-eez, a hard candy sort of deal. Both are found in the cold and flu section at Wal-Mart. These two products contain zinc and are the only two products that have scientific proof to limit the duration and effect of the common cold, and are allowed to say this in advertising by the FDA. That helps prevent a cold.
Now, if you do happen to get a cough..go to your doctor and get a prescription for Tessalon Pearles. I'm not sure of the spelling, but their a tiny little yellow "pearl" that has a gel in it. They stop a cough from a cold pretty good.
However, if I ever get a nagging cough again, I might try this thing.