Mouth ulcers (canker sores): symptoms, causes and treatment – advice from a dentist in Agadir

What is a mouth ulcer?

Mouth ulcers, also called canker sores or aphthous ulcers, are small, shallow sores that form on the soft, movable lining inside the mouth: the inner cheeks, the tip and sides of the tongue, the inner lips, the soft palate, the floor of the mouth or the loose gum at the base of the teeth. They do not appear on the gum firmly attached to the bone, on the hard palate or on the dry outer part of the lips.

They are very common, can start in childhood and become less frequent after the age of 50. People prone to them often have several flare-ups a year. They are usually harmless, but some more severe forms need a consultation.

How to recognise a canker sore

A canker sore begins with a burning or tingling sensation, followed by a painful red spot that quickly turns into an ulcer. There is usually only one, but a single flare-up can bring several (up to six).

• A round or oval ulcer, 2 to 10 mm across.
• A yellowish or greyish base with a sharp red border.
• The sore does not bleed.
• Pain is worse when eating (acidic, spicy or salty food) and when brushing the teeth.

Are canker sores contagious?

No. Canker sores are not caused by an infection, so they cannot be passed on by kissing or by sharing a glass or cutlery. That is the main difference from a cold sore (oral herpes), which usually appears on the outer edge of the lip as a cluster of small blisters, and which is contagious.

What causes mouth ulcers?

The exact cause is unknown, but several factors seem to trigger them:

• Tiredness and stress.
• Dental problems and small injuries to the lining of the mouth: a bite, a broken or sharp tooth, rubbing from a brace or an ill-fitting denture, brushing too hard.
• Certain foods: walnuts, peanuts, strawberries, pineapple, citrus fruit (lemon), figs, tomatoes, hard cheese…
• Certain medicines: non-steroidal anti-inflammatories (NSAIDs), beta-blockers, bisphosphonates, anticoagulants…
• In some women, menstruation.

The different types of canker sores

An ordinary canker sore does not usually need medical advice. It heals on its own: the ulcer loses its regular shape, its edges blur, and it disappears within 10 to 15 days without a scar. There are, however, rarer forms:

• Recurrent canker sores: more than six flare-ups a year, coming back very often and disrupting daily life.
• Herpetiform ulcers (miliary aphthosis): a large number of tiny ulcers (50 to 100), each less than a millimetre across.
• Major (giant) canker sores: 1 to 2 cm across, they can take a month to heal and may leave a scar.

Recurrent mouth ulcers: when to see a dentist

If your ulcers do not heal, keep coming back, are very large or come with other symptoms (fever, unusual tiredness, digestive problems, genital or eye lesions), see your dentist promptly. Any mouth ulcer that lasts more than two to three weeks should be examined by a professional.

Recurrent canker sores can point to an underlying condition:

• A deficiency in vitamin B9 (folate), vitamin B12 or iron.
• A digestive disease: coeliac disease (gluten intolerance) or an inflammatory bowel disease such as Crohn's disease.
• An immune deficiency.
• Behçet's disease.

How to treat a canker sore

For a simple canker sore, applying ice calms the pain. A baking-soda mouth rinse also eases the symptoms thanks to its soothing and antiseptic properties: dissolve two teaspoons of baking soda in a large glass of water and rinse your mouth for a few minutes after brushing. A local treatment, for example with chlorhexidine, can help if the pain is hard to bear. During a flare-up, avoid acidic, spicy or very salty food and use a soft toothbrush (see our oral hygiene tips).

For severe ulcers, your dentist may prescribe, depending on the case:

• Painkillers (paracetamol).
• A local preparation containing a numbing (topical anaesthetic) agent.
• Antiseptic mouthwashes, to prevent secondary infection when the immune system is weakened.
• Possibly a topical corticosteroid.
• In some cases, an oral corticosteroid treatment.

Mouth ulcers: see a dentist at Centre Dentaire BAHA in Agadir

At Centre Dentaire BAHA in Agadir, an oral examination confirms whether the sore really is a canker sore, looks for a local cause (a sharp tooth, a brace or denture that rubs, tooth decay or inflamed gums) and leads to a suitable treatment. For recurrent or unusual ulcers, the dentist can refer you to your doctor for further tests (blood test, deficiency or digestive work-up). Severe pain or a spreading sore can be seen quickly as a dental emergency — including if you are visiting Agadir on holiday.