The original study came out a year ago and is linked here:
http://www.thefastertimes.com/clinicalupdate/2010/05/14/maybe-were-not-allergic-to-everything-after-all/ Even allergy testing can misdiagnose allergies. Only testing plus a history of anaphylaxis after eating a certain food can diagnose a truly life threatening food allergy.
I knew kids who were allergic to things when I was in grade school. The kids simply avoided eating these foods and were fine.
Now we have histrionic parents claiming that their kids will die if someone in the same room is eating a peanut butter sandwich. Clearly these parents are insane, but on the off chance one has been proven right, perhaps the wisest course would be to hold the child out of school while desensitization is pursued. That child won't be able to control everything in the big wild world when he grows up, so he'd better get treatment now rather than bullying a whole school full of children and their parents and then dying in college when he walks into a pub that has beer nuts on the bar.
Food allergies are serious business and some can be life threatening. However, they're being oversold and overhyped. Any allergy that is serious enough that just being in the same room with a food triggers a life threatening reaction requires treatment. The rest can simply avoid the triggering foods and be fine.