- Simple canker sores. These may appear three or four times a year and last up to a week. They typically occur in people ages 10 to 20.
- Complex canker sores. These are less common and occur more often in people who have previously had them.
What Causes Canker Sores?
The exact cause of most canker sores is unknown. Stress or tissue injury is thought to be the cause of simple canker sores. Certain foods -- including citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes, and strawberries) -- can trigger a canker sore or make the problem worse. Sometimes a sharp tooth surface or dental appliance, such as braces or ill-fitting dentures, might also trigger canker sores.
Some cases of complex canker sores are caused by an underlying health condition, such as an impaired immune system; nutritional problems, such as vitamin B-12, zinc, folic acid, or iron deficiency; or gastrointestinal tract disease, such as celiac disease or Crohn's disease.
Are Cold Sores and Canker Sores the Same Thing?
No. Although cold sores and canker sores are often confused with each other, they are not the same. Cold sores, also called fever blisters or herpes simplex type 1, are groups of painful, fluid-filled blisters. Unlike canker sores, cold sores are caused by a virus and are extremely contagious. Also, cold sores typically appear outside the mouth -- usually under the nose, around the lips, or under the chin -- while canker sores occur inside the mouth.
What Are the Symptoms of Canker Sores?
You may have a canker sore if you have:
- A painful sore or sores inside your mouth -- on the tongue, on the soft palate (the back portion of the roof of your mouth), or inside your cheeks
- A tingling or burning sensation before the sores appear
- Sores in your mouth that are round, white or gray, with a red edge or border
In severe canker sore attacks, you may also experience:
- Physical sluggishness
- Swollen lymph nodes
How Are Canker Sores Treated?
Pain from a canker sore generally lessens in a few days, and the sores usually heal without treatment in about a week or two. Cankers sores treated with dental lasers exhibit almost complete relief of the symptoms immediately. Talk to your dentist about the procedure.
Can Canker Sores Be Prevented?
Although there is no cure for canker sores, and they often recur, you may be able to reduce their frequency by:
- Avoiding foods that irritate your mouth, including citrus fruits, acidic vegetables, and spicy foods
- Avoiding irritation from gum chewing
- Brushing with a soft-bristled brush after meals and flossing daily, which will keep your mouth free of foods that might trigger a sore
You should call your dentist about canker sores if you have: