A trip to town and food allergies

Well today has me wondering if perhaps there is a new underlying allergy to food we haven't found yet. We picked sissy up from school and she decided to share her peanut butter sandwich with her brother. Same bread, same peanut butter, but a reaction. First the peanut butter is thick so I think he kept coughing because it went down wrong, he proceeded to throw up. Not a huge deal he had thrown up after drinking water before too, but then he started getting little red hives (like he did the first time to McDonald's Frappes) so I asked and triple asked and yep I lost it with sissy (she has been told to never share her food with her brother because we try not to restrict her foods, but for whatever reason today she did), So we are pretty sure she didn't cross contaminate the sandwich but again it came from school.

We drove on to Target and his face (just on the right side) was red and irritated, wiped it off and noticed he had peanut butter on his ear. Wiped it off and went to get the one pouch of baby food  he will eat! At the checkout his eye was redder and he had more little hives again...I am not sure what it was he came into contact with but I may have to do a skin reaction test on his back (so he can spread it to find out if it was the actual peanut butter or if it was contaminated from sissy's lunch bag)

I think to me his food allergies are my greatest, nope I KNOW THEY ARE my greatest concern. It scares me to think how fast his hives can spread or how fast he can go to the first stages of anaphylaxis on us. Been there, done that, would rather never do it again.

The only thing the allergist can suggest is avoiding the culprits... (Maybe I should build him a bubble, you know like the movie about the boy who lived in a bubble... Same concept)

Anyway I gave him a half Benadryl chewable, he fell asleep (he hadn't had a nap yet) and when he woke up the redness and hives were gone completely. I am thankful that for the small cross contamination Benedryl works but it gets real too fast when it doesn't.

Then I wonder about daycare, is it even a possibility with a child who is that sensitive, (I read all the time parents getting upset because they have to accommodate other kids food allergies, but what if they knew it could be the last time that child ate because it was an inconvenience)... But then you have cross contamination of toys, desks, markers... The only way it's possible would be if every kid washed their hands upon entering the school and after every snack and meal.... Ohhhhhhh the thoughts are freaky! Over reactive? Over protective??? Nope it's just that food allergies are just that serious...

Update: after writing this earlier I talked to Montana's teacher. It was most likely a cross contamination for the bag of cheese balls in her lunch. Montana said she debated on eating them first but grabbed her sandwich, milk proteins transferred from her hands to her sandwich to her brother... :/    Thankfully and fingers crossed that is all it was!