10945 Canker Sores

Overview

Canker sores (also called aphthous ulcers) are small, shallow sores that form inside the lips, cheeks, under the tongue, or on the gums. They are not contagious and usually heal on their own in 1 to 2 weeks.

Yes, canker sores are very common. About 1 in 5 people get them at some point in life.

Anyone can get a canker sore, but they are more common in teenagers and younger adults. Women and people assigned female at birth get them slightly more often.

Symptoms

Common symptoms

• A painful sore inside the mouth, usually on the inner lip, inside the cheek, or under the tongue
• A round or oval sore with a white, gray, or yellow center and a red border
• A burning or tingling feeling before the sore appears
• Pain that gets worse when eating, drinking, or talking

Symptoms in children

• Canker sores in children look the same as in adults and can make eating uncomfortable.
• If your child refuses to eat or drink, or complains of mouth pain, check for a sore.

Symptoms in older adults

• Older adults may notice canker sores take slightly longer to heal, and they may be mistaken for other mouth problems.
• If a sore lasts more than two weeks, see a healthcare professional.

Causes

Main causes

• The exact cause is not always clear.
• Minor injury to the mouth, such as biting your cheek, brushing too hard, or dental work
• Foods that irritate the mouth, like citrus fruits, tomatoes, spicy foods, or vinegar
• Stress or emotional upset
• Hormonal changes, such as during menstruation
• A family history of canker sores

Risk factors

• Being a teenager or young adult
• Having a family member who gets canker sores often
• Having certain health conditions, such as inflammatory bowel disease, celiac disease, or a weakened immune system
• Food allergies or sensitivities

When to see a doctor

See a doctor urgently if:

• A sore that does not heal within 3 weeks
• Sores that keep coming back frequently or get worse
• Severe pain that limits eating or drinking

Book a routine appointment if:

• You have a canker sore and also have a fever, rash, or diarrhea
• You notice sores after starting a new medication (but do not stop medication without talking to your doctor)
• You want advice on reducing how often you get them

Diagnosis

A healthcare professional usually diagnoses a canker sore by looking at it and asking about your symptoms and medical history. No tests are usually needed.

Tests that may be done

• None in most cases. If a sore looks unusual or does not heal, your doctor may take a small sample (biopsy) to rule out other causes.
• In some cases, blood tests may be done to check for conditions like celiac disease, low iron, or vitamin deficiencies.

What to expect at your appointment

The doctor will examine the inside of your mouth and may feel the glands in your neck. They will ask about how long the sore has been there, what it feels like, and whether you have had them before. If further tests are needed, you will be told what they are for.

Treatment

Treatment aims to relieve pain and help the sore heal. Many canker sores get better on their own. For stubborn or very painful sores, there are prescription options that your healthcare provider can discuss with you.

Self-care at home

• Rinse your mouth gently with warm salt water (half a teaspoon of salt in a glass of warm water) a few times a day.
• Avoid spicy, acidic, salty, or crunchy foods that can irritate the sore.
• Apply a small amount of an over-the-counter protective paste to the sore, following the instructions on the package.
• Keep your mouth clean with good brushing but be gentle around the sore.
• Drink cool fluids through a straw to reduce pain when drinking.

Medical treatments

If home care is not enough, a doctor or dentist may recommend prescription mouth rinses, anti-inflammatory creams or sprays, or other topical treatments to reduce pain and inflammation. Some medications that can be applied directly to the sore may contain mild numbing agents. Never use any medication without a healthcare provider's guidance.

When is surgery considered?

Surgery is not normally used for canker sores. Some large or very painful sores may be treated with a special procedure called cautery, where a doctor or dentist uses a chemical or heat to seal the sore and reduce pain. This is not common and is only done when necessary.

Living with this condition

Most canker sores heal within 1 to 2 weeks. While they are present, try to be gentle with the inside of your mouth. Keep eating soft, cool foods and stay hydrated.

Lifestyle tips

• Avoid known triggers such as certain foods or stress.
• Use a soft-bristled toothbrush to reduce irritation.
• Take time to relax and manage stress, for example with breathing exercises or gentle activity.

Diet and exercise

There is no specific diet for canker sores, but eating soft, bland foods may help during a flare-up. Avoid very hot, spicy, or sour foods. Staying physically active and eating a balanced diet supports overall health and may help reduce stress.

Mental health and emotional wellbeing

Frequent or painful canker sores can be frustrating and make eating or talking uncomfortable. If they affect your quality of life, talk to your healthcare provider. It is normal to feel annoyed, but they are usually not serious.

Prevention

You cannot always prevent a canker sore, but you can reduce how often they appear by avoiding triggers, managing stress, and keeping a healthy mouth. If you notice certain foods make them worse, try to avoid those foods.

Complications

If left untreated

• Canker sores usually heal on their own and do not cause complications.
• Rarely, a sore that does not heal can be a sign of another condition, so it is important to see a doctor if it lasts more than three weeks.

Long-term outlook

The outlook for canker sores is very good. Most heal in one to two weeks without any scarring. If you get them often, talk to your healthcare provider about ways to reduce their frequency.

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