Most mouth ulcers are harmless and quickly resolve themselves, but may be irritating and painful as medical student Yimeng Zhang points out.

A mouth ulcer, also known as an oral or mucosal ulcer, occurs when the surface tissue of the mouth is dead and then sloughs off. They are round or oval sores which appear in the mouth, most often on the inside of the cheeks. They’re usually white, red, yellow or grey in colour and are red and swollen around the edge.

Mouth ulcers may form individually or multiple ulcers may appear at the same time and once formed, the ulcer can become inflamed and/or infected. They are very common and most people get one or two every year. Most mouth ulcers are harmless with no serious underlying cause and they cannot be caught from someone else.

The main complaint of a mouth ulcer is that they can be painful when eating, drinking or when brushing teeth. However, depending on the cause, the symptoms can vary and include swollen skin around the ulcer as well as irritation by salty, sour or spicy foods. So, they could alter the choice of food taken and cause a loss of appetite. With severe ulcers you can also have a fever, the feeling of being weak and sluggish as well as swollen lymph nodes.

Mouth ulcers can be caused by various factors but local trauma is one of the most common. This may result from rubbing on a sharp edge of a broken or misaligned tooth, biting one’s cheek and also damage during brushing. Other causes include: constant rubbing against braces or dentures; poor oral hygiene; burns from eating hot food; certain drugs and chemicals such as antiseptics (e.g. certain mouthwashes) and medications (e.g. pain killers, beta-blockers, etc); and infectious diseases such as herpes (cold sores) or thrush.

Occasionally, mouth ulcers can be caused by more serious problems or underlying health conditions such as an impaired immune system; viral infections which target the gastrointestinal system; nutritional problems such as vitamin B12, zinc, folic acid or iron deficiency; gastrointestinal diseases; cancer of the lip; syphilis infection; and many other diseases such as AIDS and diabetes.

The pain from a mouth ulcer generally settles within a few days and heals without treatment in a week or two

Canker sores (also known as aphthous stomatitis) affect around 20 per cent of people. They are recurrent mouth ulcers but there is no definite known cause. The tiny off-white ulcers can appear during times of emotional stress or menstrual period. Some researchers believe that they can be caused by an immune system reaction triggered by a virus or an allergic reaction, but they could also be due to stress, anxiety, certain foods, hormonal changes or stopping smoking.

It is difficult to know how to prevent recurrent mouth ulcers as the exact cause is unidentified; however, here are some tips to help reduce the risk:

•Use a soft toothbrush;

•Avoid hard or sharp-edged foods;

•Avoid irritation from gum chewing;

•Find ways to relieve stress;

•Maintain good oral hygiene, including brushing your teeth at least twice a day, brushing after each meal and flossing daily;

•Have regular check-ups at the dentist;

•Eat a healthy and well-balanced diet rich in vitamins;

•Manage any underlying diseases such as diabetes mellitus and inflammatory bowel disease appropriately.

The pain from a mouth ulcer generally settles within a few days and heals without treatment in a week or two. They normally do not cause any lasting problems, however, large ulcers may potentially leave a scar.

To manage an ulcer, one can try avoiding foods which make the ulcer worse, drink plenty of fluids, regularly rinsing the mouth with warm and slightly salted water and keep the mouth clean. There are some gels which can protect the ulcer or can relieve the discomfort.

If the ulcers are large, painful or persistent, one might be prescribed certain local or oral pain relief by a doctor or dentist.

Most mouth ulcers are harmless and quickly resolve themselves. Ulcers caused by infection or the aphthous type would need medical treatment. One should seek advice from a doctor or dentist if ulcers last longer than three weeks, keep coming back, are unusually large, start spreading, if one is in severe pain despite pain medication, experience difficulty in drinking fluids or if the ulcers come with high fevers.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.