I am gluten-intolerant. This means that I am unable to eat wheat, rye,oat, barley without severe stomach distress. I also suffer from a break-out of canker sores if I happen to slip and eat a gluten-laden product. It's also called celian disease. Just today I was at mass and received communion. Well, the host is made out of wheat, and I forgot, and wham! My mouth, tongue and throat is covered in canker sores. I can barely eat or swallow. So, yes, I do believe canker sores can be a symptom of food allergies. Good luck.