K.R.
DId you nurse? DId you eat these things while nursing? Did your son develop hives, barfing, or any other symptoms when he nursed these things?
My kids barfed up peanuts and cashew/pistachio/mangoes (those last three are in the poison ivy allergy family--who knew?) when I ate them as a nursing momma, or when they ate them as little people. They can eat a limited amount now; I've never really tried a full-bore "eat them as a normal food" experiment. I think I started trying them on those foods around 2. I still mostly avoid them (when I haven't eaten them for 8 years, I just don'tthink to buy them anymore).