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Canker sore

Canker sore

Alternative Names

Canker sore, Aphthous ulcer, Mouth ulcer

What is Canker sore

Canker sore is a condition characterized by development of small, shallow lesions on the soft tissues in the mouth (under your tongue, inside your cheeks or lips) and at the base of the gums. Canker sores are round or oval with a white or yellow center and a red border. They are not contagious. However, they may be very painful and make eating and talking difficult. They usually go away on their own in a week or two.

Signs and symptoms

Usually canker sores are:

Round or oval in shape
White, red, yellow or grey in colour
Inflamed around the edge

These ulcers can be added by other symptoms such as:

Fever
Listlessness
Swollen lymph nodes

Possible complications

Canker sores may lead to oral thrush (a type of mouth infection) or other Candida infections. Bacterial infections such as cellulitis and Ludwig's angina may occur. But they are rare.

What causes

The causes of canker sores may be:

A minor injury to your mouth from dental work, overzealous brushing, sports mishaps, spicy or acidic foods or an accidental cheek bite
Food sensitivities to chocolate, coffee, strawberries, eggs, nuts, cheese and highly acidic foods such as pineapple
Food allergies
A diet lacking in vitamin B-12, zinc, folate (folic acid) or iron
An allergic response to certain bacteria in the mouth
Helicobacter pylori
Celiac disease
Inflammatory bowel diseases
Behcet's disease
A faulty immune system
HIV/AIDS which suppresses the immune system
Hormonal shifts during menstruation
Emotional stress
Toothpastes and mouth rinses containing sodium sulfate

Prevention

To reduce the risk of canker sores recurring you should:

Avoid foods that can irritate your mouth including nuts, chips, pretzels, certain spices, salty foods and acidic fruits such as pineapple, grapefruit and oranges.
Choose healthy foods to prevent nutritional deficiencies, eat plenty of fruits, vegetables and whole grains.
Do not chew and talk at the same time as it may cause minor trauma to the delicate lining of your mouth.
Follow good oral hygiene habits.
Protect your mouth.