I think a lot of people are allergic to different foods and dont know it. If you get a stomach ache you might be allergic to whatever you ate that day. But if you just shit it out and go on your way you wont think much about it.I've been dealing with it my whole life, and never even realized I might be allergic until I was talking to my wife about how I hate that nuts make my mouth itchy. But it's not that bad, mostly the roof of my mouth, which is easy to get to with my tongue, so that's how I scratch it.