Possible food allergy

Patient: It seems that as of 3-4 weeks ago after i eat i get welts. they are usually on my waistline, arms, legs and sometimes on my chest. today however my upper lip in the middle got it and swelled up. the first time it happened i thought it was something that i ate at the thai place. but it has happened a ton lately. and im just realizing it seems to be after i eat that it happens. i have never had a food allergy that i know of before this. its not rampant or all over when it happens. usually a couple big ones on my waist and then a few little ones on my arm or leg.