Symptom

Mouth sores and canker sores

Mouth sores and canker sores are common and often bothersome problems in which small, round or oval sores appear on the mucous membrane of the mouth. They are typically painful and located on the lining of the lips, cheeks, or tongue. Canker sores are the most common form of mouth sore: they recur at varying intervals and usually heal on their own within 1–2 weeks without treatment. Sores larger than 1 cm are less common.

The most common causes of canker sores and mouth sores in Finland are mechanical injury to the mucous membrane (for example a bite or a dental procedure), stress, mild infections, and individual predisposition. Sometimes the background may involve a nutrient deficiency or, in rare cases, an underlying disease. Most often the symptoms are harmless, even though they can cause discomfort when eating or speaking.

Serious causes are rarely associated with mouth sores, but if a sore does not heal within 2–3 weeks, if sores appear repeatedly, or if you have severe pain, fever, general symptoms, or notice other unusual changes in the mouth, it is important to seek assessment from a healthcare professional. A professional will investigate the background of the symptom, rule out rarer causes, and refer you for further tests if needed.

Frequently asked questions

What can cause canker sores or mouth sores?

The most common causes of mouth sores include accidentally biting yourself, stress, or a mild infection. If sores occur often or do not heal, you should contact a healthcare professional.

Can I treat mouth sores at home?

Most small canker sores and sores heal on their own. Good oral hygiene and avoiding irritating foods can help. If the pain is severe or the sore does not heal, see a professional.

When should I worry about mouth sores?

If a mouth sore does not heal within 2–3 weeks, or if it is accompanied by severe pain, fever, or other unusual symptoms, it is a good idea to seek assessment from a healthcare professional.

Can mouth sores be linked to an underlying illness?

In some cases, recurrent or long-lasting mouth sores can be linked to underlying illnesses or nutrient deficiencies. If you suspect this, contact a healthcare professional.