I'm not allergic to many things, other than a wee bit of hay fever. And perfume/cologne.
My "smelly stuff" allergy has gotten worse as I've gotten older. And I get more than just a runny nose, as I discovered when an officemate came into the office on a saturday all decked out and doused in perfume (although to be fair, she had a cold, so she may not have realized exactly how much she was wearing). I can deal with a constantly runny nose. After about 10 minutes, what I could not deal with was a massive, pounding headache and a general feeling that my entire respiratory system was clogging. I didn't feel better until the next day, and my nose ran for a couple days after that.
I am not a hypochondriac or a medical weirdo. I know I am not the only person sensitive to strong perfumes. Please, please, please: When you attend a meeting or a conference where you can reasonably expect to sit close to people you haven't met, for the love of God, don't add any extra scents. Except deodorant, of course. There's nothing like spending an entire day (or several days) stuck in a miasma that makes you feel like you're contracting an exotic disease.
Incidentally, if you're a lover of fine perfumes, and somebody suggests that maybe you're coming on a little too strong, smell-wise, you are. Nobody is going to go up and mention it to you unless it's a real problem. And if someone tells you "other people have noticed this" it means that a significant number of people at the office/conference/meeting were overpowered by your smell and that you need to tone it down, stat.