I have an allergy to mold that I didn’t discover until I stayed at a friends house for a few weeks several years ago.
I was having the worst allergic reactions until I decided to see a lung, allergy, and respiratory specialist.
They ran a few tests and took samples to see what was going on with my body’s aggressive histamine response. The specialists figured out that I was allergic to mold, tree pollen, and soybeans after questioning me extensively following my test results. I had signs of mold exposure in my body and was given medication to improve my respiratory issues. In the years since, I have gone out of my way to avoid dealing with mold in any capacity. It’s really hard because it seems to be as ubiquitous in human living spaces as dirt or dust. Some people are great about protecting their homes and the indoor air quality from these dangerous airborne contaminants, but others either don’t care or can’t detect the mold themselves. The range of the human olfactory response is massive. If we compared it to vision, two people within the “normal” olfactory range could differ as much as a blind person and one with 20-20 vision. I might test at “normal” for my nose’s ability to detect odors in the environment, but I pick up things that others don’t. My window air conditioner starts to smell moldy if you use it for too long without cleaning it. I will start noticing an issue that my girlfriend doesn’t. I get out the a/c cleaning spray and she will ask me why, claiming that the window a/c isn’t dirty yet. She just doesn’t have the same mold sensitivity that I do.