Mouth ulcers

What are mouth ulcers?

A mouth ulcer is the loss or erosion of part of the delicate tissue that lines the inside of the mouth (mucous membrane).

There are many things that cause mouth ulcers. The most common cause is injury (such as accidentally biting the inside of your cheek). Other causes include aphthous ulceration, certain medications, skin rashes in the mouth, viral, bacterial and fungal infections, chemicals and some medical conditions.

An ulcer that won’t heal may be a sign of mouth cancer.

In most cases, mouth ulcers are harmless and resolve by themselves within 10 to 14 days without the need for treatment.

Aphthous ulcers

Aphthous ulcers are recurring ulcers which affect around 20 per cent of the population. Although in most people there is no known cause for aphthous ulcers, in a small number of people these ulcers may be due to an underlying Vitamin B, folate or iron deficiency.

Aphthous ulcers generally occur on the softer mouth lining of the lips, cheeks, sides of the tongue, floor of the mouth, back of the roof of the mouth and around the tonsil area. These ulcers are usually no larger than 5mm. You may develop more than one aphthous ulcer at a time, and sometimes these ulcers are joined together. These ulcers generally resolve within 10 to 14 days, but often they recur at varying intervals of time.

Mouth ulcers that won't heal

See your dentist or doctor if your mouth ulcers don’t clear up within 2 weeks, or if you get them frequently.

It is important not to ignore an ulcer that you have had for more than 2 weeks, especially if you use tobacco products and/or drink alcohol regularly. This is because tobacco use and drinking alcohol both (individually and together) increase your risk of mouth cancer.

Symptoms of mouth ulcers

The symptoms of a mouth ulcer depend on the cause, but may include:

• One or more painful sores on part of the mucous membrane lining the mouth.
• Swollen and red mucous membrane around the sores.
• Problems with chewing or tooth brushing because of the tenderness.
• Irritation of the sores by salty, spicy or sour foods.
• Irritation of the sores by dentures, orthodontic aligners or mouth splints.
• On occasions an ulcer may not be sore. This can occur in cases of mouth cancer.

Causes of mouth ulcers

Mouth ulcers can be caused by a wide range of factors including:

• Accidentally biting the inside of your cheek.
• Injury from a toothbrush (such as slipping while brushing).
• Constant rubbing against misaligned or sharp/broken teeth.
• Constant rubbing against dentures or braces.
• Burns from eating hot food.
• Irritation from strong antiseptics, such as a mouthwash.
• Aphthous ulcers.
• Viral infections such as the herpes simplex viral infection (cold sore virus).
• Reaction to certain medications.
• Skin rashes in the mouth (for example, lichen planus).
• Autoimmune diseases.
• Underlying Vitamin B2, folate or iron deficiency.
• Underlying gastrointestinal disease such as Crohn’s disease or coeliac disease.
• Mouth cancer.
• Ulcers may become worse during periods of stress, illness or extreme fatigue.

When to seek treatment for mouth ulcers

If ulcers are interfering with your normal daily activities, or have persisted for more than 2 weeks, see your dentist or an Oral Medicine Specialist dentist.

In some cases, you may need blood tests if it is suspected that you have an underlying deficiency (such as an iron, folate or vitamin B deficiency) or an inflammatory medical condition.

If your oral health professional cannot determine the cause of your mouth ulcers, or if the ulcers do not respond to the normal treatments, you may need to have a biopsy of part of the ulcer and some of the surrounding tissue. A biopsy is a procedure where a tissue sample is taken for examination and diagnosis.

Treatment for mouth ulcers

Most mouth ulcers are usually harmless and resolve by themselves within 10 to 14 days. Other types of mouth ulcers, such as the aphthous variety or those caused by herpes simplex infection or skin rashes in the mouth need topical treatment (such as a mouthwash, ointment or gel).

It’s not possible to speed up the recovery of ulcers, but the symptoms can be managed, and the risk of complications reduced.

Treatment options for mouth ulcers include:

• Avoid spicy, salty and sour foods until the ulcers heal.
• Drink plenty of fluids.
• Keep your mouth clean.
• Apply antiseptic gel to the ulcers.
• Rinse your mouth out with warm, slightly salted water, keeping the rinse in your mouth for up to 4 minutes at a time. Repeat four times daily.
• Use an alcohol-free medicated (preferably containing chlorhexidine gluconate) mouthwash twice daily.
• Use a topical alcohol-free steroid mouthwash or ointment – this is generally prescribed by your dentist or Oral Medicine Specialist.
• If required in severe cases, immunosuppressant medication may be prescribed by your oral health professional or appropriate medical specialist.

Prevention of mouth ulcers

Mouth ulcers can be avoided in some cases by:

• Brushing your teeth gently with a soft toothbrush, taking care not to slip with the brush.
• Eating a well-balanced and nutritious diet.
• Making sure that underlying medical conditions are well-controlled.

Where to get help

• Dentist or Oral Medicine Specialist dentist
• Your GP (doctor)
• Pharmacist
• Australian Dental Association – Find a Dentist Tel. (03) 8825 4600
• Dental Health Services Victoria provides public dental services through the Royal Dental Hospital of Melbourne and community dental clinics for eligible people. For more information about public dental services, Tel. (03) 9341 1000 or 1800 833 039 outside Melbourne metro.