Our son has major food allergies, and has to carry a epi pen. Should I get a note from his ped saying he has to carry the epi and that we have to bring all his food? I dont want it to be a hassle at the gates over this.
My son also has severe food allergies. First time we took him to Disney, he was also 3. At that time, I had no idea how wonderful Disney was with food allergies! Now we don't bother worrying about snacks (but with a toddler, they need them). All the counter service places have ingredient info, and at any sit down place, just let them know you have a family member with allergies. A chef will come speak to you to see what your needs are, and go from there! They are wonderful! My son eats better at Disney then any other vacation spot.
Also for flying, we have medicine, and they never give us a hard time going through security. I usually have one bag full of meds - inhalers, liquids for his nebulizer, benedryl, epipens, etc... We do have to pack snacks for a flight, or eat at McDonald's at the airport right before flying (yuck, I know, but they have things he can eat at least).
You'll be fine going into the parks, they do just have to check the bags. It's not as highly scrutinized as the airport.
Oh - my son's allergist also wrote a great book, "Food Allergies for Dummies", by Dr. Robert Wood. I read it, and wished my family and my in-laws had read it when my DS was younger. It had so much great info.
