Mouth ulcers are painful, small lesions that form in the mouth or at the base of the gums. They can make eating, drinking, and talking difficult.
Types of mouth ulcers include canker sores and the sores caused by hand, foot, and mouth disease.
Mouth ulcers are rarely contagious and usually heal on their own after 1 to 2 weeks, even if left untreated. Seek the advice of a doctor or dentist if you develop a large, painful mouth ulcer that does not heal after a long period of time.
Causes of mouth ulcers
Mouth ulcers have no known cause, but certain risk factors and triggers have been identified.
People born female, children, adolescents, and those with a family history of mouth ulcers have a higher risk of developing them.
Triggers include:
- Minor mouth injury from dental work, hard brushing, sports injury, or an accidental bite
- Dental braces
- Toothpaste or mouthwash that contains sodium lauryl sulfate (SLS)
- An allergic response to oral bacteria
- Bacterial, viral, or fungal infections in the mouth, such as hand, foot, and mouth disease
- Sensitivities to acidic foods and beverages like strawberries, citrus fruits, pineapple, chocolate, and coffee
- Certain nutrient deficiencies, especially vitamin B9 (folate), vitamin B12, zinc, and iron
- Hormonal changes, such as those that occur during menstruation or pregnancy
- Emotional stress
- Lack of sleep
Mouth ulcers can also be a sign of conditions that are more serious and require medical treatment, such as:
- Celiac disease
- Inflammatory bowel disease (IBD), including ulcerative colitis
- Diabetes
- HIV
- Oral lichen planussome autoimmune diseases, including: lupus and Behçet’s disease, a rare condition that causes inflammation throughout the blood vessels.
Symptoms of a mouth ulcer
Mouth ulcer symptoms vary depending on the cause, but they typically include:
- painful sores that may be yellow, white, or red
- sores on the inside of the mouth, such as on your tongue or the insides of your cheeks or lips
- areas of redness surrounding the sores
- pain that worsens when you eat, drink, or talk
You may have more than one mouth ulcer at the same time.
Mouth ulcers are not usually contagious unless they’re caused by an infection such as hand, foot, and mouth disease.
When should you see a doctor or dentist?
Consult a doctor or dentist about your mouth ulcers if you experience any of the following symptoms:
Mouth ulcers that are unusually large
New mouth ulcers form before the old ones heal
Sores that last longer than three weeks
Sores that don’t hurt
Sores that reach the lips
Pain that you can’t get rid of with over-the-counter or natural remedies
Severe eating and drinking difficulties
High fever or diarrhoea whenever your mouth ulcers appear