The diagnosis of canker sores (including Sutton disease 2) is usually based on clinical examination and medical history. There are no laboratory procedures available for definitive diagnosis. In some cases, tests may be used to check for other health problems, especially if the canker sores are severe or ongoing (lasting more than 10 to 14 days). Dentists and/or professionals trained in oral medicine can assist in the diagnosis.

Treatment may not be necessary for minor canker sores which tend to clear on their own over the course of a week or two. Large, persistent or unusually painful sores may require medical care. The goals of treatment are to decrease pain, speed healing and avoid recurrence. While no one therapy meets all of these goals, many do offer some benefit. Treatment may include mouth rinses, topical ointments or systemic corticosteroids.