I have suffered with canker sores and geographic tongue (it's real -- check it out) for many years. Sometimes the sores are so bad that I can hardly eat or talk (my husband likes that part). I have talked with my doctor and dentist, but they have not been helpful. Thanks to the Internet, I think I have found a possible solution to my problem.
I recently attended a baby shower where one of the games was identifying nursery rhymes. I won! I don't know what that says about me, but we "older" women had a distinct advantage over the young 'uns. Probably since nursery rhymes are considered old fashioned and so last millennium. Anyway, my prize for winning the contest was a giant (ie. from Costco) bag of Hot Tamales. I love Hot Tamales, but that much! I brought them to school for my TAs to eat, but apparently they don't like them.
One day I ate several hands full throughout the day and I got really bad canker sores on the right side of my mouth. The worst case ever! This was the moment I got serious about the research. I thought that it must be a connection to something in the Hot Tamales, so I looked for allergies to cinnamon oil. There are people who have bad reactions to the oil, but it is more like the typical allergies with hives and itching and stuff. I only had cankers sores.
Today while I was passing out the candy to my classes, one student said that there was some acid in them that could kill you in large amounts. I doubted that, so I looked for the ingredients in Hot Tamales. None of the acids looked that deadly: citric acid, sodium citrate, pectin, malic acid, and fumaric acid. All food grade. I was a little disturbed by the carnuba wax. Don't I wax my car with that? The biggest revelation was that there is no cinnamon oil in Hot Tamales, just an artificial cinnamon oil. Just when I thought I had figured it out!
Another Google search put me in touch with this site: http://voices.yahoo.com/artificial-cinnamon-flavor-cause-8987855.html?cat=5. There were some other sites about this topic, but they wouldn't open. It is not a widespread problem suggested by the lack of sources, but if you chew Big Red gum, eat Hot Tamales, or brush with cinnamon toothpaste and get cankers sores, then you might be part of the small number of us with this weird allergy.