At a preschool I interned at, they had a list of all the kids right on the wall. Partly for attendance and partly because it was color-coded for various allergies. I think red was more serious ones that would require an epi-pen, which was readily available from the staff nurse.

But honestly, if an allergy is so serious that it will kill the kid and they don't know what to look out for by the time they're 6ish... it's kind of Darwinism.