A canker sore is a shallow sore shaped like a crater (ulcer) on your tongue or on the inside of your lip or cheek. Canker sores have a red border and a white or yellow centre. They may be painful and can make it hard to talk and eat. You may have one or more than one canker sore at a time. Unlike cold sores, you cannot spread canker sores to other people.
Anyone can get a canker sore but women, teenagers, and young adults have them more often. People usually get their first canker sore between the ages of 10 and 40. Most people have canker sores at some time in their lives, and some people have them regularly.
The cause of canker sores is unknown, but they tend to run in families. Canker sores may also develop when you:
Canker sores usually begin with a burning or tingling feeling. They may be swollen and painful. Having a canker sore can make it hard to talk or eat.
Canker sores may hurt for 7 to 10 days. Minor canker sores heal completely in 1 to 3 weeks, but major canker sores can take up to 6 weeks to heal. Some people get another canker sore after the first sore has healed. Most canker sores heal without a scar.
You do not need to see a doctor for most canker sores. They will get better on their own. There are many things you can try at home to relieve the pain caused by your canker sores:
If your canker sores do not feel better after trying these steps at home for 2 weeks, you may need to see your doctor or dentist. He or she may recommend medicines that will help the pain caused by your canker sores. Usually these medicines are swished or gargled in your mouth, or they are painted on the sore. Your doctor may prescribe steroid cream (triamcinolone or fluocinonide) to rub on your canker sore and/or a prescription mouthwash to use.
Talk to your doctor if you have a fever, have trouble swallowing, or if your canker sores keep coming back. You may have another problem that is causing your symptoms.