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Causes

By Mayo Clinic staff

The precise cause of canker sores remains unclear, though researchers suspect that a combination of several factors contributes to outbreaks, even in a single individual. These factors include:

  • A faulty immune system that attacks healthy cells in your mouth instead of pathogens such as viruses and bacteria
  • A minor injury to your mouth from dental work, overzealous brushing, sports mishaps, spicy or acidic foods, or an accidental cheek bite
  • An allergic response to certain bacteria in your mouth
  • Helicobacter pylori, the same bacteria that cause peptic ulcers
  • A diet lacking in vitamin B-12, zinc, folate (folic acid) or iron
  • Celiac disease, a serious intestinal disorder caused by a sensitivity to gluten, a protein found in most grains
  • Inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis
  • Behcet's disease, a rare disorder that causes inflammation throughout the body, including the mouth
  • HIV/AIDS, which suppresses the immune system
  • Food allergies or sensitivities
  • Certain foods, particularly chocolate, coffee, strawberries, eggs, nuts, cheese and highly acidic foods, such as pineapple
  • Hormonal shifts during menstruation
  • Emotional stress
  • Toothpastes and mouth rinses containing sodium lauryl sulfate

DS00354

Jan. 31, 2008

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