Canker Sores

Diagnosis

Mild canker sores (simple aphthosis) are common and usually heal within one to three weeks. These short-lived sores cause only minimal pain and are located only in the mouth. Patients should see a doctor if they have six or more episodes per year or if they have continuous ulcers.

Only 5 percent of patients with canker sores have severe canker sores (complex aphthosis) — persistent, painful sores that don't heal. Patients may also have genital lesions. Approximately two-thirds of people with complex aphthosis have one or more associated conditions, such as an intestinal or blood disease, or a deficiency of iron, folic acid, vitamins B-6 or B-12 or zinc. These patients should have a thorough medical evaluation, including blood tests. When testing reveals a serious illness, patients are referred to appropriate specialists.