Aphthous Ulcer - Causes and Epidemiology

Causes and Epidemiology

Canker sores are a very common oral lesion. Epidemiological studies show an average prevalence between 15% and 30%. The frequency of canker sores varies from fewer than 4 episodes per year (85% of all cases) to more than one episode per month (10% of all cases) including people suffering from continuous recurrent aphthous stomatitis.

The exact cause of many aphthous ulcers is unknown but citrus fruits (e.g., oranges and lemons), physical trauma, lack of sleep, sudden weight loss, food allergies, immune system reactions, and deficiencies in vitamin B₁₂, iron, and folic acid may contribute to their development. Nicorandil and certain types of chemotherapy are also linked to aphthous ulcers. One recent study showed a strong correlation with allergies to cow's milk. Aphthous ulcers are a major manifestation of Behçet disease, and are also common in people with Crohn's disease.

Trauma to the mouth is the most common trigger. Physical trauma, such as that caused by toothbrush abrasions, laceration with sharp or abrasive foods (such as toast or potato chips/crisps), accidental biting (particularly common with sharp canine teeth), after losing teeth, or dental braces can cause aphthous ulcers by breaking the mucous membrane. Other factors, such as chemical irritants or thermal injury, may also lead to the development of ulcers. Using a toothpaste without sodium lauryl sulfate (SLS) may reduce the frequency of aphthous ulcers. One smaller study found no connection between SLS in toothpaste and aphthous ulcers. While a more recent study (from 2012) concluded that SLS-free did not reduce the number of ulcers and episodes, but it did affect the ulcer-healing process and reduces pain in daily lives in patients with recurrent aphthous stomatitis. Celiac disease has been suggested as a cause of aphthous ulcers and some patients benefited from eliminating gluten from their diets.

There is no indication that aphthous ulcers are related to menstruation, pregnancy, or menopause. Smokers appear to be affected less often.