I have been allergic to Red 40 and Blue 1 since I was about 5 or 6...it was and still is very hard to find things that do not contain those dyes. It was harder as a child though, since most food for children is chockful of unnatural colors.
I watch what I eat as much as I can. Unfortunately, being allergic to two of the three primary colors rules out basically everything.
My reactions have gotten milder as I've gotten older and I can usually control the symptoms with Benadryl.
Ironically enough, I'm allergic to the dye in Benadryl. They make a dye-free version though, luckily.
It doesn't make much sense (to me anyway) that they would make allergy medicine one of the colors that people are allergic to.