The precise cause of canker sores remains unclear, though researchers suspect that a combination of factors contributes to outbreaks, even in the same person.
Possible triggers for canker sores include:
- A minor injury to your mouth from dental work, overzealous brushing, sports mishaps or an accidental cheek bite
- Toothpastes and mouth rinses containing sodium lauryl sulfate
- Food sensitivities, particularly to chocolate, coffee, strawberries, eggs, nuts, cheese, and spicy or acidic foods
- A diet lacking in vitamin B-12, zinc, folate (folic acid) or iron
- An allergic response to certain bacteria in your mouth
- Helicobacter pylori, the same bacteria that cause peptic ulcers
- Hormonal shifts during menstruation
- Emotional stress
Canker sores may also occur because of certain conditions and diseases, such as:
- 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
- A faulty immune system that attacks healthy cells in your mouth instead of pathogens, such as viruses and bacteria
- HIV/AIDS, which suppresses the immune system
Unlike cold sores, canker sores are not associated with herpes virus infections.
March 19, 2015
- Canker sores. FamilyDoctor.org. http://familydoctor.org/familydoctor/en/diseases-conditions/canker-sores.html. Accessed Feb. 15, 2015.
- Canker sores. American Academy of Oral Medicine. http://www.aaom.com/index.php?option=com_content&view=article&id=82:canker-sores&catid=22:patient-condition-information&Itemid=120. Accessed Feb. 15, 2015.
- Canker sores. American Dental Association. http://www.ada.org/en/Home-MouthHealthy/az-topics/c/canker-sores. Accessed Feb. 15, 2015.
- Recurrent aphthous ulcerations. American Academy of Oral and Maxillofacial Pathology. http://www.aaomp.org/public/aphthous-ulcerations.php. Accessed Feb. 15, 2015.
- Mouth sores and inflammation. The Merck Manual Home Edition. http://www.merckmanuals.com/home/mouth_and_dental_disorders/symptoms_of_oral_and_dental_disorders/mouth_sores_and_inflammation.html. Accessed Feb. 15, 2015.
- Recurrent aphthous stomatitis. The Merck Manual Home Edition. http://www.merckmanuals.com/home/mouth_and_dental_disorders/symptoms_of_oral_and_dental_disorders/recurrent_aphthous_stomatitis.html. Accessed Feb. 15, 2015.
- Goldstein BG, et al. Oral lesions. http://www.uptodate.com/home. Accessed Feb. 15, 2015.
- Stoopler ET, et al. Oral mucosal diseases: Evaluation and management. Medical Clinics of North American. 2014;98:1323.
- Belenguer-Guallar I, et al. Treatment of recurrent aphthous stomatitis: A literature review. Journal of Clinical Experimental Dentistry. 2014;6:e168.
- Akintoye SO, et al. Recurrent aphthous stomatitis. Dental Clinics of North America. 2014;58:281.
- Salinas TJ (expert opinion). Mayo Clinic, Rochester, Minn. March 3, 2015.
- Gibson LE (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 27, 2015.
You Are ... The Campaign for Mayo Clinic
Mayo Clinic is a not-for-profit organization. Make a difference today.