Ulcers are painful sores that appear inside the mouth. They are usually red or yellow. They are different from cold sores, which appear on the outer lips and are caused by a virus.
Usually a single mouth ulcer is due to damage caused by biting the cheek or tongue, or by sharp teeth, brushing or poorly fitting dentures. These ulcers are called ‘traumatic' ulcers. If you have a number of mouth ulcers, and they keep coming back, this is called ‘recurrent aphthous stomatitis'.
Traumatic ulcers are usually on their own, are next to the cause of the damage and go away once the source of the problem is removed.
Recurrent aphthous stomatitis is a common problem, and is the repeated appearance of mouth ulcers in otherwise healthy children and young people. The cause is not known, but it is not infectious and is unlikely to be inherited.
Minor ulcers are the most common. They can appear inside the cheeks, and on the lips, tongue and gums and, more rarely, on the roof of the mouth. Most of these ulcers are the size of the top of a pencil and can sometimes come in clusters. You can get four to six at any one time.
Large ulcers are more severe and can take longer to heal. Any ulcer that lasts longer than 3 weeks should be checked by your dentist. Large ulcers may appear near the tonsils and can be very painful, especially when you swallow. You usually, only get one at a time.
It is also possible to have up to 100 very small, painful ulcers which last for one to two weeks. However, these last two varieties are very rare.
Infections can cause mouth ulcers. Herpes simplex often causes mouth ulcers in children and some adults. Other less common viral and bacterial infections may cause mouth ulcers, but this is rare. Mouth ulcers can be caused by anaemia and occasionally by other blood disorders, and some skin or gastrointestinal diseases. Sometimes the mouth ulcers are the only sign of an underlying disease.
Cancer of the mouth can first appear as a mouth ulcer. The ulcers caused by mouth cancer are usually single and last a long time without any obvious nearby cause (for example a sharp tooth). Any ulcer that lasts longer than three weeks should be looked at by your dentist. Ulcers caused by cancer usually appear on or under the tongue, but may occasionally appear somewhere else in the mouth. Cancer of the mouth is usually linked to heavy smoking and drinking. Doing both together greatly increases the risk.
Mouth ulcers cannot be caught by kissing, or by sharing drinks and utensils.
The treatment depends on the cause of the ulcers. Sometimes all that is needed is for a sharp tooth to be smoothed down or a denture adjusted, although some patients may need mouthwashes or tablets.
If an ulcer lasts more than 3 weeks you should always ask your dental team or doctor for advice. They may be able to tell you the cause and provide treatment, or they may arrange more tests or refer you to a specialist if needed.
You may be able to reduce the risk of mouth ulcers by:
Most ulcers heal up on their own. However, if they don't heal within three weeks you should visit your dentist. Your dental team will be able to examine your mouth to check that the problem is an ulcer and not something more serious such as mouth cancer. If you suffer from ulcers that come and go often, you should visit your dental team to check that there is not an underlying medical cause.
Always see your dental team or doctor if: