Overview

A canker sore, also known as an aphthous ulcer, is a small, shallow ulcer that appears inside the mouth. These painful sores commonly develop on the inner cheeks, lips, tongue, or gums and are not contagious. Canker sores are among the most frequent causes of mouth ulcers and usually resolve on their own within one to two weeks. While generally harmless, they can cause discomfort while eating, drinking, or speaking. In some cases, recurrent or unusually large canker sores may indicate an underlying health condition.

Causes

The exact cause of canker sores is not always clear, but several factors are known to trigger or increase the risk of their occurrence:

• Minor mouth injuries: Biting the inside of the cheek, dental work, or using sharp dental appliances like braces.
• Stress: Emotional stress or fatigue can trigger outbreaks in some individuals.
• Dietary factors: Acidic or spicy foods, such as citrus fruits, tomatoes, and hot peppers, can irritate the mouth lining.
• Vitamin deficiencies: Lack of vitamin B12, folic acid, zinc, or iron has been associated with recurrent canker sores.
• Hormonal changes: Fluctuations in hormone levels, especially in women, can lead to more frequent sores.
• Immune system reactions: Some people develop canker sores due to immune system malfunction, where the body attacks healthy cells in the mouth.
• Food allergies or sensitivities: Reactions to certain foods or additives, like gluten, can trigger sores in sensitive individuals.
• Underlying medical conditions: Conditions such as celiac disease, inflammatory bowel disease (IBD), and Behçet’s disease can include recurrent canker sores as a symptom.

Symptoms

The typical symptoms of a canker sore include:

• Small, round or oval ulcers: Usually white or yellowish in the center with a red border.
• Pain or burning sensation: Pain, especially during eating, drinking, or speaking, typically peaks within a few days.
• Location: Found inside the mouth, commonly on the soft tissues like the inner cheeks, lips, tongue, and soft palate.
• Tingling or burning before onset: Many people experience a tingling or burning feeling before the sore appears.
• Occasional swelling: Mild swelling of nearby tissues may occur.
• Absence of fever: Canker sores usually do not cause fever or systemic symptoms, unless part of an underlying disease.

Diagnosis

Canker sores are typically diagnosed through a simple physical examination:

• Clinical examination: A healthcare provider can identify a canker sore based on its characteristic appearance.
• Medical history: Discussing frequency, triggers, and any associated symptoms helps rule out other causes.
• No special tests required: Most cases do not need laboratory tests or biopsies.
• Further testing: In cases of frequent, severe, or unusually large canker sores, blood tests may be ordered to check for nutritional deficiencies, celiac disease, or autoimmune disorders.

Treatment

Most canker sores resolve without treatment, but several methods can ease discomfort and speed healing:

• Home remedies: Rinsing with warm salt water or baking soda solution can soothe the sore.
• Topical treatments: Over-the-counter gels, pastes, or creams (e.g., benzocaine) provide pain relief and form a protective barrier.
• Mouth rinses: Antimicrobial or corticosteroid mouth rinses may be prescribed for more severe cases.
• Pain relievers: Ibuprofen or acetaminophen can reduce pain if necessary.
• Dietary changes: Avoiding spicy, acidic, or sharp foods can prevent irritation during healing.
• Nutritional supplements: Correcting vitamin or mineral deficiencies may help reduce recurrence.
• Medical treatment: For frequent outbreaks, a doctor may prescribe medications like corticosteroids or immunomodulators.

Prognosis

The prognosis for canker sores is generally excellent:

• Self-limiting condition: Most canker sores heal naturally within 7 to 14 days without scarring.
• Recurrence possible: Some people experience occasional or frequent recurrences, but these can usually be managed with simple treatments.
• Good response to treatment: Pain and healing time often improve with topical or prescribed treatments.
• Underlying causes: When related to nutritional deficiencies or medical conditions, treatment of the root cause reduces recurrence.
• No serious health risk: While painful, canker sores are benign and do not lead to serious health issues in most individuals.

With proper care and identification of triggers, most people can manage canker sores effectively and minimize their impact on daily life.