Mouth ulcers, also known as aphthous ulcers or canker sores, are a type of sore that occurs on the inside of your mouth. They can feel uncomfortable, especially when you are talking, eating, drinking and brushing your teeth. In most cases, mouth ulcers are not dangerous and heal on their own. Around 1 in 5 people experience recurrent mouth ulcers.
What do mouth ulcers look like?
Mouth ulcers look like a shallow sore with a white/grey top and a red rim. They can occur as a single ulcer or in a cluster.
Mouth ulcers can appear in different locations around the mouth. Common locations include:
- inside the lips
- inside the cheeks
- on the bottom of the mouth or the gums
- on the tongue
What causes mouth ulcers?
No one knows the exact cause of mouth ulcers, but there are several factors that can make you more likely to develop them.
Mouth ulcers may be caused or triggered by:
About 1 in 3 people who get mouth ulcers have family members who also get them.
When should I see my doctor?
You should see your GP if you think you might have an ulcer related to a mouth infection or disease.
Most mouth ulcers will heal by themselves within a week or two. If your mouth ulcers last longer than this or they keep coming back, see your doctor, as they may be a sign of a more serious problem.
Also, see your GP if you or your child develops severe mouth ulcers with symptoms of general illness such as:
- weight loss, stomach pain, unexplained fevers
- mucus or blood in their stool (poo)
- neck stiffness and tiredness
- ulcers around the anus
This may indicate a health condition such as coeliac disease or inflammatory bowel disease.
How are mouth ulcers diagnosed?
Your doctor can usually diagnose a mouth ulcer by simply looking at it.
Your doctor may also ask you questions about your symptoms, diet, medical history and what medicines you regularly take.
If your doctor thinks that your mouth ulcer is infected, they may swab the ulcer to confirm an infection and help determine the right treatment.
How are mouth ulcers treated?
Most of the time, mouth ulcers heal on their own without treatment within a week. You can relieve any discomfort with a numbing anaesthetic mouth gel applied to the area, which you can buy over-the-counter from pharmacies.
If you are experiencing a lot of pain from your mouth ulcers, ask your doctor about other pain relief options.
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Canker Sore (Aphthous Ulcer)
Written by WebMD Editorial Contributors
Medically Reviewed by Sabrina Felson, MD on May 12, 2021
In this Article
- What Is a Canker Sore?
- Canker Sore Causes and Risk Factors
- Canker Sore vs. Cold Sore
- Canker Sore Symptoms
- Canker Sore Diagnosis
- Canker Sore Treatment
- Canker Sore Home Remedies
- Canker Sore Prevention
A canker sore is a small, shallow open wound (or ulcer) in your mouth that can make eating and talking uncomfortable. They’re also known as aphthous ulcers. There are a few types of canker sores: Doctors don’t know what exactly causes most canker sores. Things that might cause minor sores include: Things that might cause complex canker sores include: About 1 in 5 people gets canker sores regularly. They’re more common in women, possibly because of hormonal differences. They may also run in families. Canker and cold sores aren’t the same. Cold sores, also called fever blisters or herpes simplex type 1, are groups of painful, fluid-filled blisters. Unlike canker sores, a virus causes cold sores, and they’re highly contagious. Also, cold sores typically appear outside your mouth -- usually under your nose, around your lips, or under your chin -- but canker sores show up inside your mouth.What Is a Canker Sore?
Canker Sore Causes and Risk Factors
Canker Sore vs. Cold Sore
You may have a canker sore if you have: Severe canker sore attacks may also cause: Canker sores usually aren’t serious. Call your dentist if you have: They can usually make a diagnosis based on a physical exam and your medical history. They might want to test your blood to see whether a vitamin deficiency or another health condition is causing the sores. Pain from a canker sore tends to get better in a few days, and the sores usually heal without treatment in about a week or two. Treatment for large, long-lasting, or unusually painful sores might include:Canker Sore Symptoms
Canker Sore Diagnosis
Canker Sore Treatment
Home treatments to speed healing and help you feel better include: There’s no cure for canker sores, and they often come back. But you might get them less often if you:Canker Sore Home Remedies
Canker Sore Prevention
What does sores in the mouth indicate?
How do you get rid of inside mouth sores?
What virus causes sores inside mouth?