I'm not allergic to tobacco, but I have pretty bad asthma and so does my son. It's not usually a problem at work, but nearly everyone in my family smokes. I manage to avoid them for weeks at a time, and my visits there consist of little more than my wife talking to them while my son and I go play with toys in another room. It's great for bonding with my son, not so great for my relationship with the rest of them. On the other hand, spending my life in another room allowed me to spend all of my time at the computer, leading to a decent career.