Off and on for years I've gone on coughing fits. It wasn't often, then in recent years it became once or twice a winter for a couple of weeks, then it started happening last summer and returned this winter. It can be violent. I have hernias to show for it. When I'm in the throes, I cough after eating, when talking and after getting out of the shower.
I finally broke down and went to the ENT doc, who did allergy testing. I am mildly allergic to a number of things, but the worst ones turned out to be ragweed and mold. Mold makes sense because my basement is damp, and I cough more in the winter when the house is closed up. Then I noticed something on the shower wall this morning. It's a fine white powder. Is this mold?
I clean the shower wall with Comet. This seems like residue from that. But — and not to be gross here — but I'm a bachelor who is not a neat freak and if I clean the shower walls four times a year, that's a good year. (Relax, like you're ever going to take a shower in my house. Jesus.) So I would assume the Comet left over from the cleanings should be gone after, oh, 90 showers.