by Malavi Sivakanesan • 12 March 2025 • 6 min read
Do you keep getting mouth ulcers? These small, painful sores can make eating, drinking, and even talking uncomfortable. The causes of mouth ulcers can vary from minor injuries and food sensitivities to stress, infections, and even medical conditions. While some ulcers appear as a one-time occurrence, others may keep coming back. Understanding what causes mouth ulcers can help you take the right steps to prevent and treat them effectively.
Common Causes of Mouth Ulcers
Minor Injuries & Trauma
If you bite your cheek accidentally, brush your teeth harshly, or get irritated from braces, the soft tissue within your mouth may get hurt. These small injuries tend to cause ulcers. If your mouth ulcer keeps coming back in the same place, repeated trauma may be the cause.
Stress
Does stress cause mouth ulcers? And does anxiety cause mouth ulcers too? Sadly, yes. Excessive stress and anxiety can weaken your immune system. Weak immunity will make it harder to fight off infections and heal properly. This can make you more prone to developing painful sores in your mouth.
Additionally, stress-related habits like teeth grinding, biting your cheek or lip, and skipping meals can further irritate the mouth, increasing the chances of ulcers.
Nutritional Deficiencies
A poor diet with a deficiency of vitamin B12, iron, or folic acid is one common reason for ulcers in the mouth. All these nutrients are necessary to keep tissues healthy, and their deficiency causes a delay in healing and makes you more prone to ulcers. You must maintain an optimal diet by consuming all the necessary vitamins.
Food Allergies & Sensitivities
Some foods, such as acidic and spicy foods, irritate the lining of the mouth and cause ulcers. If you see ulcers developing after consuming certain foods, you might have a mild allergy or sensitivity. Try to avoid them as much as possible to prevent mouth ulcers.
Mouth Ulcers Due to Underlying Health Conditions & Medication Side Effects
Although occasional mouth ulcers are normal, frequent or recurring sores can be a sign of an underlying medical condition such as:
Gum Disease & Mouth Ulcers
Gum disease occurs when bacteria build up along the gumline. The early stage of gum disease is called gingivitis. It causes red, swollen gums that may bleed when brushing or flossing. If left untreated, it can progress to periodontitis, a more severe condition where the gums pull away from the teeth, creating pockets that trap bacteria.
This ongoing irritation and infection can weaken the soft tissues inside your mouth and make you more prone to painful gum disease mouth ulcers. Proper gum treatment is essential to prevent and manage such gingival ulcers.
Autoimmune Conditions
Certain autoimmune conditions, like lupus, Behçet's disease, and celiac disease, can cause chronic mouth ulcers. These occur when the immune system mistakenly attacks healthy cells, leading to inflammation and sores inside the mouth.
Unlike common ulcers, these can be more frequent, painful, and slow to heal. If you experience persistent mouth sores along with other symptoms like skin rashes, joint pain, or digestive issues, it's important to consult a doctor for proper diagnosis and treatment.
Medication Side Effects
Drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs) and some chemotherapy treatments can irritate the mouth lining, which leads to ulcers. Along with these, medications that weaken the immune system or cause dehydration may also increase the risk of ulcers.
How to Prevent Mouth Ulcers?
While mouth ulcers can sometimes be unavoidable, certain habits can help reduce their occurrence and severity. Here are some simple ways to prevent them:
- Practise good oral hygiene: Brush and floss your teeth daily to avoid bacterial accumulation. Use a soft-bristled toothbrush to prevent accidental cuts and bruises.
- Maintain a balanced diet: Intake adequate vitamin B12, iron, and folic acid to minimise the risk of ulcers caused by nutrient deficiency.
- Avoid spicy foods: Eating spicy or acidic foods can irritate the inside of your mouth and lead to ulcers. If certain foods seem to trigger your ulcers, try to avoid them.
- Stay Hydrated: Drink plenty of water throughout the day to keep your mouth moist, support saliva production, and prevent ulcers.
- Quit smoking: Tobacco irritates the lining of the mouth, making you more prone to mouth ulcers.
When to See a Dentist?
Mouth ulcers can be extremely annoying, but most heal on their own within a week or two. However, if an ulcer lasts for multiple weeks or becomes unusually large and painful, do not make the mistake of ignoring it. Sometimes, persistent ulcers can be a sign of an underlying health issue, an infection, or even cancer.
Precaution is always better than cure, so book a consultation with Complete Smiles to get a dentist's opinion about your persistent ulcers.
Malavi Sivakanesan
Malavi Sivakanesan is the principal dentist and co-founder at Complete Smiles in Harrow, Greater London. She is responsible for establishing the Complete Smiles brand throughout the United Kingdom and Europe and has 5 successful practices under her strong leadership.