Mouth Ulcers
Painful sores inside the mouth
Quick Facts
- Type: Oral (mouth) condition
- Common form: Canker sores (aphthous ulcers)
- Typical course: Heal in 1-2 weeks
- Not the same as: Cold sores, which are caused by a virus
Overview
Mouth ulcers are painful sores that develop inside the mouth, including on the inner cheeks, gums, tongue, and lips. The most common type is the canker sore, also called an aphthous ulcer, which is a small, round or oval sore with a white or yellow center and a red border.
Most mouth ulcers are harmless and heal on their own within one to two weeks. They are not contagious and are different from cold sores, which appear on the outside of the lips and are caused by a virus. While usually minor, mouth ulcers can make eating, drinking, and talking uncomfortable, and frequent or unusually large sores sometimes point to an underlying issue.
Symptoms
Mouth ulcers are usually easy to recognize.
- One or more painful sores inside the mouth
- A round or oval shape with a white, yellow, or gray center
- A red, inflamed border around the sore
- A tingling or burning feeling before the sore appears
- Pain that worsens with eating, drinking, or talking, especially with acidic or spicy foods
Most sores are small, but larger ulcers can take longer to heal and may leave a scar. Multiple or recurring sores can occur in some people.
Common Causes
The exact cause of canker sores is often unclear, but several factors can trigger or contribute to mouth ulcers.
- Minor injury: Accidentally biting the cheek, a sharp tooth, braces, or vigorous brushing
- Irritating foods: Acidic, spicy, or salty foods in sensitive people
- Stress and hormonal changes: Often linked with flare-ups
- Nutritional deficiencies: Low iron, vitamin B12, or folate
- Certain toothpastes: Some ingredients can trigger sores in some people
- Underlying conditions: Some illnesses, including immune and digestive conditions, can cause recurrent ulcers
Associated Symptoms
Most mouth ulcers occur on their own, but additional symptoms can be a clue to an underlying cause and are worth mentioning to a clinician.
- Fever, fatigue, or feeling generally unwell with the sores
- Ulcers elsewhere on the body, including the genitals or eyes
- Swollen glands in the neck
- Diarrhea, abdominal pain, or weight loss, which may point to a digestive condition
- Frequent, severe, or unusually large or long-lasting ulcers
Diagnosis & Evaluation
Mouth ulcers are usually diagnosed by looking at them, and most need no testing.
- Examination and history: A clinician looks at the sores and asks about how often they occur and any other symptoms.
- Blood tests: May be done for frequent ulcers to check for nutritional deficiencies or underlying conditions.
- Biopsy: Rarely, a sample is taken from a sore that does not heal to rule out other causes.
Treatment & Management
Most mouth ulcers heal without treatment, but several measures can ease discomfort and speed comfort.
- Pain relief gels and rinses: Over-the-counter products can numb the area or protect the sore.
- Salt-water or baking-soda rinses: Can soothe and keep the area clean.
- Avoid irritants: Steer clear of acidic, spicy, salty, or rough foods while the sore heals.
- Topical treatments: Some contain mild corticosteroids for more painful ulcers.
- Address underlying causes: Correcting a deficiency or changing toothpaste may help recurrent ulcers.
If sores are frequent or severe, a doctor or dentist may prescribe stronger treatments or look for an underlying condition.
When to See a Doctor
See a doctor or dentist if a mouth ulcer lasts longer than two to three weeks, is unusually large, keeps coming back, or is so painful that you cannot eat or drink. Frequent ulcers along with fever, fatigue, or sores elsewhere on the body should also be evaluated.
Have any mouth sore that does not heal, bleeds, or is hard and painless checked promptly, as a non-healing sore can rarely be a sign of a more serious condition that benefits from early evaluation.
Frequently Asked Questions
Are mouth ulcers the same as cold sores?
No. Mouth ulcers (canker sores) form inside the mouth, are not contagious, and have no known viral cause in most cases. Cold sores appear on the outside of the lips, are caused by the herpes simplex virus, and are contagious.
How long do mouth ulcers take to heal?
Most heal on their own within one to two weeks without leaving a scar. Larger ulcers may take longer. A sore that lasts more than two to three weeks should be checked by a doctor or dentist.
What helps with the pain?
Over-the-counter numbing gels, protective pastes, and salt-water or baking-soda rinses can ease discomfort. Avoiding acidic, spicy, salty, and rough foods while the sore heals also helps reduce irritation.
Why do I keep getting mouth ulcers?
Recurrent ulcers can be triggered by stress, minor mouth injury, certain foods or toothpastes, hormonal changes, or nutritional deficiencies such as low iron or vitamin B12. Frequent ulcers can also signal an underlying condition, so it is worth seeing a doctor.
When should a mouth ulcer worry me?
See a doctor or dentist for an ulcer that lasts longer than two to three weeks, is very large, keeps recurring, or comes with fever or sores elsewhere. Any non-healing, bleeding, or hard painless sore should be checked promptly.
References
- Mayo Clinic. Canker sore.
- American Academy of Oral Medicine. Recurrent Aphthous Stomatitis.
- MedlinePlus, U.S. National Library of Medicine. Canker sores.
- National Health Service (NHS). Mouth ulcers.