Family doctor

What is a mouth ulcer?

 A mouth ulcer is a breach or break in the mucous membrane which lines the inside of the mouth. It usually looks like a depression in the mucous membrane and usually has a yellow or white colour. The size may vary from a millimetre or less in diameter to several centimetres. It is often painful.

What are the most common types of mouth ulcers?

There are many different types of mouth ulcers. The two most common types are

1) ulcers caused by minor injuries and

2) aphthous ulcers.

 1)Ulcers caused by minor injuries:

If a person has a sharp edge on a tooth (for example, because the tooth is chipped), or poorly fitting dentures, the mucosal lining of the mouth may be injured and this may result in an ulcer. These ulcers usually heal rapidly if the source of the injury is removed (for example, if poorly fitting dentures are removed or replaced).

 2)Aphthous ulcers:

Most people probably get aphthous mouth ulcers at some time in their life. Usually the first attack occurs in adolescence or young adulthood. These ulcers are usually small (less than 5 mm in diameter) and painful. There may be just one or two at a time, or there may be very numerous ulcers in the mouth. People with this condition usually feel fairly well apart from the pain in their mouth. The ulcers usually heal in 1 to 2 weeks but they tend to recur at intervals over the course of many years. In some cases recurrences can be so frequent that mouth ulcers may be constantly present for prolonged periods.

Occasionally, aphthous ulcers can be much larger (more than a centimetre in diameter), and then they can take months to heal. These large ulcers are called 'major aphthous ulcers'.

People may feel pain or tingling in the mouth for a day or two before aphthous ulcers break out. It's best to start treatment at this time if possible.

The exact cause of aphthous ulcers is unknown but it is thought that they may result from the body's own immune system attacking the mucosal lining of the mouth. They may occur after minor injury to the inside of the mouth. Aphthous ulcers are more likely to occur at times of stress. They may occasionally occur after eating certain foods. They may be more common when certain hormones circulate; they tend to be more common round about the time of a menstrual period but less common during pregnancy. Sometimes aphthous ulcers can be caused by deficiency in vitamin B12, folic acid or iron. In rare instances, aphthous ulcers may be caused by coeliac disease (coeliac disease is a condition caused by an inability to tolerate gluten in the diet). A blood test can be used to test for coeliac disease.

Viral infections causing mouth ulcers:

Several different types of viral infections can result in ulcers forming in the mouth and throat.

The herpes simplex virus can cause an illness known as primary herpetic gingivostomatitis. This illness is most common in children. Numerous small painful ulcers occur on the lips, in the mouth and in the throat. There is usually a fever and the glands in the neck are enlarged. The child is usually miserable and may have difficulty eating and drinking because of the pain.

Another viral infection called hand, foot and mouth disease is most common in preschool children. Small ulcers occur in the mouth and little blisters also occur on the hands and feet of the child.

Healthy people with normal immunity recover rapidly from most viral infections in the mouth and throat; people suffering from the viral illnesses described above usually recover completely after a week or two.

Mouth cancer:

Most mouth ulcers are caused by relatively harmless conditions. However, an ulcer in the mouth may sometimes be the first sign of a mouth cancer. Any sore or ulcer in the mouth which is unexplained and not healing should be checked carefully by a general practitioner or specialist in case it might be a cancer. This is particularly important for older people and smokers, because mouth cancer is more common in these groups.

What are the other causes of mouth ulcers?

There are a great many other conditions which can cause mouth ulcers. These can include infections; abnormalities of the blood; adverse reactions to medications; and skin conditions in which rashes or ulcers may occur on other parts of the body too, not only in the mouth. People who suffer from intestinal conditions such as ulcerative colitis or Crohn's disease may also get mouth ulcers.

Ulcers can sometimes occur after radiotherapy to the head and neck region.

How are mouth ulcers treated?

Treatment of mouth ulcers may include soothing mouthwashes (such as salt and warm water or compound thymol glycerin mouthwash) or antiseptic mouthwashes such as chlorhexidine mouthwash or povidone iodine mouthwash. Pain can be relieved by using local anaesthetics such as benzydamine hydrochloride, choline salicylate gel or lignocaine. Local anaesthetics like this cause temporary numbness at the site where they are applied. These local anaesthetics may be used in the form of a mouthwash, a spray, a jelly or an ointment.  (Local anaesthetics need to be used with care: if the back of the tongue or the throat is made numb this can result in choking when swallowing food or drink. Local anaesthetics are also not suitable for young children with mouth ulcers).

Carmellose gelatin paste may be applied to mouth ulcers; it forms a protective layer over the ulcer.

Paracetamol is useful to relieve pain, especially for young children with viral infections causing mouth ulcers. Such young children need to be encouraged to drink to avoid dehydration.

Carbenoxolone gel or mouthwash can be used.

Many of the remedies above may be bought from a pharmacy without a prescription.

Treatment of aphthous ulcers may, on medical advice, include corticosteroids applied as a paste or used as a mouthwash. Occasionally it may be necessary to take corticosteroid tablets (so that they are absorbed into the bloodstream) to treat some severe types of mouth ulcer. For large aphthous ulcers, corticosteroids may sometimes be injected beneath the ulcer. Before using corticosteroids of any type it is important to be sure that the ulcers are not caused by a viral infection.

Aciclovir, a type of antiviral medication may sometimes be helpful for mouth ulcers caused by the herpes simplex virus. Aciclovir cream may be used for treatment of cold sores. It should be applied as early as possible, preferably when the tingling sensation is present but the cold sore has not yet appeared.

A mouthwash containing tetracycline (a type of antibiotic) is sometimes used for treatment of mouth ulcers. A medication called cimetidine, originally used to treat stomach ulcers, has also been used in the treatment of aphthous mouth ulcers.

Summary

Most mouth ulcers are not due to serious illness. Occasionally they can be associated with poor immunity or other medical conditions.

Ulcers that so not heal should always be checked by a doctor.