Aphthous ulcers (aka canker sores) are a painful ulcer of the mouth that occur in up to 20% of the population, with about 10% suffering recurrent episodes. They are common in young adults, may be as small as a pinhead or as large as a quarter, and are very poorly understood. Aphthous ulcers have been associated with AIDS, which may indicate an autoimmune component.
In general, no treatment is necessary, and concern should only arise when they are associated with uveitis, arthritis, fever, or adenopathy. This may point to BehÃƒÂ§et's syndrome, Reiter's syndrome or inflammatory bowel diseases, and especially Crohn's disease. Otherwise, the ulcers subside in 4-5 days and heal in 10-14 days without any intervention.