Hives

My son who has a PA allergy just broke out from some sticky rice steamed in a banana leaf....that was all the ingredients...but have found out that the restaurants' steamer steams other things with PEANUT in them. Anyways, didn't have to use epi or anything, but after two bites, his stomach turned red, hot to the touch, looked like heat rash, but within seconds that rash turned into hives, and very itchy, I gave him benadryl which calmed it a bit, he was still up most of the night scratching. Letting him sleep in this morning to catch up on sleep, and check his skin and go to school late. But someone had said...that their kids have GI problems for 48 hours after they have a hive incident, haven't heard back from her...wondering if anyone out there whose child has have hives, what do I do now, watch for? Too early to call dr. thought I would check with you parents in the meantime, thankyou