Hi. I had those cases. If it seems that doesn't affect them then I just make sure to take a picture, write an observation form indicating the foods the child has eaten the reaction (including behavior) the approx. Length it lasted and pass this information to parents. It is up to them ( and I recommend ) to try it again or mention it to their pediatrician (making easy for them to diagnose if it is a food sensitivity or allergies).

In mother of the cases I saw children react with hives to acidic food such as: tomatoes, strawberries range juice etc.

I hope it helps.