Canker sores are one of the most common oral lesions and concern the general population on all five continents2. Many epidemiological studies have been done showing high variation on prevalence. On average, we can consider that canker sores affect 15% to 30% of the general population with frequencies as high as 50% in certain social groups3 4. The age onset of minor aphthae can start as early as 5 years old whereas major aphthae generally starts after 20. Canker sores tend to afflict women more than men.
The frequency of recurring aphthous stomatitis varies from less 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 RAS4.
In the USA there are about 9 million people over 15 years old suffering from recurring canker sores with more than two forming each month. 4.2 million people have more than one crisis per month. More than 1,200,000 have canker sores more than one crisis every 2 weeks.
The datas of this chart are coming from the Swedish study of T Axéll & V Henricsson4.