I'm afraid I don't know. Scattered spots like the ones you describe could be hives, I guess, or they could be bites, but the geographic change makes bites unlikely. If they're hives, they'll go away on their own. I suggest you show them to a doctor, or take a photo in case they aren't there when you go. But food or other allergy seems very unlikely, since allergies don't look like what you're describing.
Best.
Dr. Rockoff