We Still Don’t Know What Fundamentally Causes Canker Sores
But it’s probably the immune system’s fault.
A canker sore—a painful white ulcer inside the mouth—might be brought on by stress. Or the wrong toothpaste. Or certain foods: tomatoes, peanuts, cinnamon. Or an iron deficiency. Or an allergy. Or a new prescription. Or an underlying autoimmune disease.
Even though millions of people suffer from them every year, researchers still don’t know much about what fundamentally causes these sores. This leaves doctors and dentists stuck playing detective with their patients—running down a checklist, trying to figure out which of more than a dozen potential triggers could’ve set off the
