- Patient Education
A canker sore is a small, painful sore that develops inside the mouth. Also known as 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 on their own or in groups and are recurrent.
Although canker sores can be painful, they will usually clear on their own within one to two weeks.
Although 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.
What causes canker sores?
Although the exact cause of this type of mouth ulcer is unknown, hereditary factors, stress or tissue injury are the likely causes of canker sores on the gum, tongue or soft palate. Acidic or citrus foods can also trigger a canker sore, as can sharp teeth, braces or ill-fitting dentures. Cigarette 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 problems, and gastrointestinal tract disease.
Canker sore symptoms
The symptoms of canker sores include:
A small, shallow and symmetrical ulcer that is white, gray or yellow in colour and surrounded by redness
A painful sore inside your mouth which can appear on or under the tongue, at the base of the gums, inside the cheek or lip or on the soft palate
A burning or tingling before the ulcer appears
In severe cases, a canker sore may be accompanied by one or more of the following symptoms:
Swollen lymph nodes
If you are suffering from a canker sore and any of the above symptoms you should visit your dentist or physician.
Canker sore treatment
Although canker sores can be painful at first, 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.
You are also recommended to rinse the mouth with a warm-water solution and avoid eating any acidic, citrus or spicy foods that may irritate the ulcer.
How to prevent canker sores
Although incurable, you may be able to prevent canker sores and reduce their frequency by doing the following:
Avoid chewing gum which can cause irritation
Avoid citrus fruits, acidic vegetables and spicy foods which may irritate the inside of your mouth
Use a soft-bristled brush to brush your teeth
Brush after meals and floss daily