If I had a child who was so severely allergic to peanuts that exposure to a small amount of airborne peanut oil could kill her, I would either home-school her or have her in an extremely isolated special class (if one were available) and I would not take her to crowded public places in general, until the allergy became less severe or she was old enough to manage it. I consider allergies of this severity to be disabilities similar to that "boy in a bubble" immune-system disorder. Because of the popularity of peanuts, esp. as a food for children, it is very difficult to ensure a total absence of every trace of peanuts in any environment crowded with children. As sad as I would be about my child's missing out on so many social experiences, I would not be willing to take the risk.
I mean, "Peanut Free zones, where kids with peanut allegies can eat their lunch safely" aren't enough if the allergy is really severe. What if a kid who ate peanut butter for breakfast and didn't wash his hands then held hands with my child during the first morning activity, or he leaned close to whisper a secret in her ear? Unless I felt absolutely confident that school staff would be able to notice her reaction immediately and use the Epipen, I would not take the risk.
I'm allergic to dogs. During the most severe stage of my allergy, approx. age 14-21, I could not tolerate being in a room with a dog---I don't THINK it was life-threatening, but it felt like it might be, as my eyes and throat would swell to the point that I couldn't see and could barely breathe after about 5 minutes' exposure. Therefore, if I was riding a bus and a Seeing Eye Dog got on, I got off at the next stop and took the next bus. It was inconvenient, but I knew it was unreasonable to expect the school for the blind to relocate away from my bus route or the blind people to stay off the transit system just because of my allergy. Once, walking down stairs in a university building, I met an enormous poodle who was bounding up the stairs and rounded a corner suddenly and jumped on me.
Its owner, who was running about one flight behind, pulled it off and apologized profusely, and I believed her explanation that Fifi had pulled away from her accidentally. I expected (and got) forgiveness from the prof of my next class when I arrived late after washing my face, arms, and legs and taking medication. I did not expect the university to ban animals from academic buildings in order to prevent this terrifying experience from happening again.
But if I were so allergic to dogs that I could die from sitting next to someone who played w/his dog this morning and still has dog hair on his shirt, I would consider that a handicap that prevents me from going out in public. Just banning dogs in public places wouldn't be sufficient to protect me; I'd have to ban people from having any contact w/dogs anywhere without going thru a decontamination process, and that just isn't reasonable unless a significant portion of the population is allergic to dogs.