Understanding Canker Sores in the Mouth: Causes, Symptoms, and Treatment

Canker sores, medically known as aphthous ulcers, are small, shallow lesions that develop on the soft tissues inside the mouth or at the base of the gums. Unlike cold sores, canker sores don’t occur on the surface of the lips and aren’t contagious. Although generally harmless, they can be painful and may make eating, drinking, and talking uncomfortable.

Types of Canker Sores

Canker sores are classified into three main types:

  1. Minor Canker Sores

    • The most common type (about 80% of cases)

    • Small, oval-shaped with a red edge

    • Heal without scarring within 1–2 weeks

  2. Major Canker Sores

    • Larger and deeper

    • Irregular edges and can be extremely painful

    • May take up to 6 weeks to heal and could leave scars

  3. Herpetiform Canker Sores

    • Numerous, tiny sores that can merge into larger ulcers

    • Rare and not caused by the herpes virus

    • Heal in about 1–2 weeks

Common Causes and Risk Factors

The exact cause of canker sores is not fully understood, but several factors are believed to trigger or increase the risk of developing them:

  • Injury to the mouth: From dental work, braces, aggressive tooth brushing, or accidental cheek biting

  • Stress: Emotional stress and lack of sleep can contribute to outbreaks

  • Dietary deficiencies: Lack of iron, folic acid, or vitamin B12

  • Food sensitivities: Acidic or spicy foods like citrus fruits, tomatoes, or chocolate

  • Hormonal changes: Especially during menstruation

  • Underlying health conditions: Such as celiac disease, Crohn’s disease, or Behçet’s disease

  • Immune system issues: Autoimmune responses may trigger ulcers

  • Sodium lauryl sulfate (SLS): A foaming agent in some toothpastes may increase risk

Symptoms of Canker Sores

  • A tingling or burning sensation a day or two before the sore appears

  • A small, round, white or yellow ulcer with a red border

  • Pain or discomfort, especially when eating, drinking, or talking

  • In severe cases: fever, swollen lymph nodes, and fatigue

Treatment and Management

Canker sores usually heal on their own, but several treatments can help ease discomfort and speed up healing:

Home Remedies:

  • Saltwater or baking soda rinses: Reduces bacteria and promotes healing

  • Milk of magnesia: Can be dabbed on the sore to coat and soothe the area

  • Hydrogen peroxide solution: Used as a gentle antiseptic rinse

Over-the-Counter Treatments:

  • Topical pastes (e.g., benzocaine, fluocinonide): Reduce pain and inflammation

  • Mouth rinses: Containing chlorhexidine or dexamethasone

  • Oral pain relievers: Such as ibuprofen or acetaminophen

Medical Treatments:

  • Prescription corticosteroids or immune-modulating medications for severe cases

  • Cauterization: Chemically or with a laser to close the ulcer and relieve pain

Prevention Tips

While canker sores can’t always be prevented, the following steps may reduce their frequency:

  • Avoid foods that irritate your mouth

  • Use a soft-bristled toothbrush and avoid toothpastes with SLS

  • Maintain good oral hygiene

  • Manage stress through relaxation techniques

  • Address any underlying nutritional deficiencies

Canker sores are a common and usually minor annoyance, but they can significantly impact daily comfort. Understanding their triggers, symptoms, and treatments can help manage them effectively. If sores are persistent or unusually severe, consulting a healthcare provider is essential to rule out more serious conditions. Our Fort Worth dentists can help provide medication to alleviate the pain caused by canker sores.