A.C.
I think that the safest thing is to completely eliminate nuts. I know it's a pain (my son tested as a 3+ for peanuts), but it's way better safe than sorry. I think that some nuts may cross react (for example, kids that are allergic to peanuts are almost always allergic to some extent to sesame seeds because the oils/proteins chemically similar). Also, facilities that use peanuts often use other nuts in other products, and that "trace of peanuts or tree nuts" might just be one of the ones he tested a 6 for.... a just a trace of that could be enough to cause anaphylactic (sp) shock.
At least get rid of anything that has "traces" until you can get a a call in, and call back from, your pediatrician, or better yet, from your allergist.