@MonicaCellio There's no such thing as an allergy to tobacco smoke. You can be allergic to nicotine (or one of the other chemicals in the smoke). You can be allergic to smoke in general (or dust or other small particles). You can have asthma. But "cigarette smoke allergy" simply doesn't exist. To have a diagnosis, you should have been given an allergy test, which will test hundreds of different potential allergens, to tell you exactly which substance you're allergic to.

@AaronF it was one of the other chemicals. I don't remember which one now; they told me after doing the test but I've failed to retain it decades later. All of this is quite tangential, though; if you don't have a verified allergy but cigarette smoke still makes you sick, you can just say you're sensitive to it. The goal in the question was a conversation, not a legal complaint.