Overview
Aphthous ulcers, commonly known as canker sores, are small, shallow lesions that develop on the soft tissues inside the mouth — including the lips, cheeks, tongue, and gums. They are one of the most common oral complaints, affecting people of all ages, though they are more frequent in adolescents and young adults.
Unlike cold sores, aphthous ulcers are not contagious and are not caused by the herpes simplex virus. They typically appear as round or oval sores with a white or yellow center and a red border. Most heal within one to two weeks without scarring, but recurrent cases can be frustrating and painful.
While aphthous ulcers are usually harmless, persistent or severe outbreaks may indicate an underlying health condition such as a vitamin deficiency, immune disorder, or gastrointestinal disease. Understanding the triggers and available treatments can help manage symptoms and reduce recurrence.
Symptoms
The primary symptom of an aphthous ulcer is a painful sore inside the mouth. Other common signs include:
- A tingling or burning sensation in the mouth one to two days before the sore appears
- Round, white or yellow sores with a red halo or border
- Pain or discomfort when eating, drinking, brushing teeth, or speaking
- Difficulty consuming spicy, acidic, or salty foods
- Swollen lymph nodes in severe cases
Most aphthous ulcers are minor and heal within 7–14 days. Major aphthous ulcers are larger, deeper, and may take several weeks to heal, sometimes leaving a scar. Herpetiform ulcers are clusters of tiny sores that can merge into larger, irregular lesions.
Causes
The exact cause of aphthous ulcers is not fully understood, but several factors can trigger or worsen them. These include:
- Stress and fatigue — emotional stress is one of the most common triggers.
- Minor mouth injury — accidental biting, dental work, vigorous brushing, or sharp foods.
- Nutritional deficiencies — low levels of vitamin B12, folate, iron, or zinc.
- Food sensitivities — acidic fruits (citrus, tomatoes), chocolate, coffee, nuts, and spicy foods.
- Hormonal changes — especially during menstruation or pregnancy.
- Immune system factors — autoimmune conditions, HIV, or inflammatory bowel disease.
- Genetic predisposition — a family history of recurrent aphthous ulcers.
- Certain medications — including NSAIDs, beta-blockers, and chemotherapy drugs.
- Oral hygiene products — toothpaste containing sodium lauryl sulfate (SLS) may aggravate ulcers in some people.
Treatment
Most aphthous ulcers heal on their own, but treatment can help relieve pain, speed healing, and reduce the frequency of outbreaks. Common approaches include:
- Topical gels and creams — containing corticosteroids, lidocaine, or benzocaine to reduce pain and inflammation.
- Antimicrobial mouthwashes — chlorhexidine or hydrogen peroxide rinses to prevent infection and promote healing.
- Pain relievers — over-the-counter medications such as ibuprofen or acetaminophen.
- Nutritional supplements — if a deficiency is identified, vitamin B12, folate, iron, or zinc supplements may help.
- Avoiding trigger foods — limiting acidic, spicy, or abrasive foods that can irritate the mouth.
- Good oral hygiene — gentle brushing and regular dental check-ups to reduce irritation.
- Stress management — relaxation techniques, adequate sleep, and regular exercise.
For severe or recurrent cases, a doctor or dentist may prescribe stronger medications, including oral corticosteroids, immune-modulating drugs, or laser therapy.
When to See a Doctor
While aphthous ulcers are usually harmless, you should consult a healthcare professional if you experience:
- Ulcers that last longer than two weeks
- Unusually large or deep sores
- Frequent outbreaks (more than a few times a year)
- Severe pain that interferes with eating or drinking
- Signs of infection, such as fever or pus
- Ulcers accompanied by other symptoms like skin rash, joint pain, or diarrhea
Your doctor may perform a physical examination, blood tests, or a biopsy to rule out other conditions such as oral cancer, herpes, or autoimmune diseases.