A canker sore is a small, painful sore that develops inside the mouth. The medical name for it is aphthous ulcers. These shallow sores can be found on or under the tongue, inside your cheek or lip, at the base of the gums, or on the soft palate. Canker sores can appear in single sores or in groups and are recurrent.

Although canker sores can be painful, they will usually clear on their own within one to two weeks. While often confused, canker sores are not like cold sores, which are caused by the herpes virus. Unlike a cold sore, canker sores do not appear on the lips and are not contagious.

The exact cause of this type of mouth ulcer is unknown, but hereditary factors, stress, or tissue injury are the likely causes of canker sores on the gum, tongue or soft palate. Acidic foods can also trigger a canker sore, as can sharp teeth, braces, or ill-fitting dentures. Smoking and allergies may also increase the likelihood of canker sores. Some cases of canker sores might highlight an underlying health condition, including nutritional and immune system issues and gastrointestinal tract disease.

Cranker sores are usually small, shallow, and symmetrical ulcer that is white, gray, or yellow in color and surrounded by redness; they are painful and can appear on or under the tongue, at the base of the gums, inside the cheek or lip or on the soft palate and sometimes burning or tingling occurs before the ulcer appears. In severe cases, a canker sore may be accompanied by one or more of the following symptoms:

  • Swollen lymph nodes
  • A rash
  • Joint Pain
  • Diarrhea
  • Fever
  • Sluggishness

If you are suffering from a canker sore and any of the above symptoms you should visit your dentist or physician.

Although canker sores can be painful, this should lessen within the first few days and the mouth ulcer should heal entirely without treatment in around one to two weeks. If your canker sore is persistent, unusually large, or particularly painful, or if the sores are spreading, your dentist may prescribe a corticosteroid ointment or antimicrobial mouth rinse. Over-the-counter solutions may also be recommended to reduce pain and irritation. It is also recommended to rinse the mouth with a warm-water solution and avoid eating any acidic or spicy foods that may irritate the ulcer.

Although incurable, you may be able to prevent canker sores and reduce their frequency by avoiding chewing gum which can cause irritation, avoiding citrus fruits, acidic vegetables, and spicy foods which may irritate the inside of your mouth, using a soft-bristled brush to brush your teeth and brushing after meals and flossing daily.