Canker sores; causes, symptoms and treatment

Canker sores are painful sores that occur in the mouth. They are round or oval in shape and are red in color, with a gray/white coating in the center of the spot. A canker sore often starts as a red dot. The bigger the ulcer becomes, the longer it generally takes before it goes away again. Canker sores occur annually in one in five people in the Netherlands, and in some people return several times a year. Reduced resistance, stress, medication use and certain intestinal diseases are some of the possible causes. Treating canker sores does not have to be difficult.

Canker sores

  • Cause of the development of canker sores
  • Symptoms of canker sores – symptoms canker sores
  • Prevention
  • Treatment of canker sores
  • When to go to the doctor with canker sores?


Cause of the development of canker sores

It is not entirely known what causes canker sores. There are various factors that can influence the development of canker sores. Moreover, one person is sensitive to it and the other is not. Factors that can influence the development of canker sores include:

  • Reduced physical resistance
  • During a period of high stress
  • Just before a period
  • Sores in the mouth; caused, for example, by biting the tongue or the inside of the cheek, by a sharp edge on a tooth or molar, by braces or improperly fitting dentures or by brushing the teeth
  • Hereditary factor; It occurs more often within a family
  • Eating irritating foods such as citrus fruits, pineapple, salty foods
  • Allergic rhinitis
  • The use of certain medications; including beta blockers and some painkillers
  • Certain diseases; intestinal diseases (Crohn’s disease, ulcerative colitis, celiac disease) and diseases associated with a lack of vitamin B 12, folic acid or iron
  • Canker sores also often recur due to hormonal changes during menstruation and sunlight


Symptoms of canker sores – symptoms canker sores

Canker sores are painful sores, gray/white with a red edge, that mainly occur on the underside of the tongue, on the inside of the cheek and the inside of the lip. One canker sore can occur, but dozens can develop in the mouth at the same time. Canker sores can cause a stabbing pain, especially if hot or acidic foods are eaten. Small ulcers generally heal spontaneously within one or two weeks. Large ulcers can take longer to heal, up to a month. A burning or stinging sensation may occur even before the sores develop.


  • Take care of your mouth regularly by brushing and flossing your teeth
  • Avoid eating irritating foods
  • Since the condition can be contagious, it is recommended to avoid intimate contact with someone with canker sores


Treatment of canker sores

Treatment of canker sores is not simple and is often aimed at pain relief and prevention of triggering factors. It is wise to ensure good physical resistance by eating a good and varied diet and getting enough rest at night. Try to avoid stressful situations for long periods of time. Take good oral care and brush gently, without making wounds. The pain can be relieved by taking paracetamol or by treating ulcers with lidocaine, which has an anesthetic effect. However, be careful when chewing and do not bite the cheek.

When to go to the doctor with canker sores?

If ulcers are present for more than two weeks and if ulcers return several times a year, it may be wise to visit the doctor. Even if there are additional complaints such as high fever or swelling in the neck glands or feeling very ill, a visit to the doctor is wise. If mouth ulcers develop after starting a new medication, it may be useful to obtain information about this from the pharmacy or doctor. If wounds regularly occur in the mouth due to teeth or molars, or due to braces or dentures, go to the dentist.