Canker Sores: What They Are, How to Relieve Pain, and When to Seek Care
A canker sore (also called an aphthous ulcer) is a small, painful mouth ulcer that usually heals on its own within 7–10 days. While not dangerous, canker sores can make eating, drinking, and speaking uncomfortable, especially for children.
From a first aid and public health education perspective, it’s helpful to know how to reduce discomfort safely and recognize when mouth sores need medical attention.
This information is for learning and awareness only, not a replacement for dental or medical care.
What Is a Canker Sore?
Canker sores typically develop:
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On the inside of the cheeks
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On the tongue
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Inside the lips or along the gums
They are not contagious, which is an important distinction from cold sores, caused by a virus and usually found on the lips.
Common triggers include:
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Minor mouth injuries (biting the cheek, dental work)
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Stress or fatigue
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Certain foods (acidic, spicy, salty)
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Toothpaste containing sodium lauryl sulfate
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Temporary immune system changes
Symptoms of a Canker Sore
A canker sore may cause:
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Localized mouth pain or burning
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Sensitivity when eating or drinking
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Difficulty chewing
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Irritation when brushing teeth
Although uncomfortable, canker sores do not cause fever and usually resolve without treatment.
Pain Relief and Supportive Care
Mouth Rinses
Gentle mouth rinses can help keep the area clean and reduce irritation.
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Saltwater rinses (warm water with a small amount of salt) can soothe discomfort
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Non-alcohol mouthwashes may reduce irritation
Some prescription mouth rinses may be recommended by healthcare professionals in recurrent or severe cases, particularly for adults.
⚠️ Important: Strong antiseptics or medicated rinses should not be used in young children unless advised by a healthcare provider.
Protective Coatings and Gels
Over-the-counter oral gels or liquids may:
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Coat the sore
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Reduce friction
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Provide temporary pain relief
Products designed for mouth ulcers are preferred, especially in children, as they are formulated for oral safety.
Home Comfort Measures
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Applying a cool compress externally to the cheek
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Drinking cool liquids
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Eating soft foods
Some people find relief using traditional remedies like placing a moist black tea bag against the sore. Black tea contains tannins, which may temporarily reduce discomfort.
Over-the-Counter Options
Certain oral pain-relief products may contain ingredients that:
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Temporarily numb the sore
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Reduce irritation
These can sting briefly when first applied. Always follow label directions and choose age-appropriate products, especially for children.
Everyday Care Tips (Especially for Children)
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Avoid spicy, acidic, or crunchy foods
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Use a soft-bristled toothbrush
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Choose toothpaste without sodium lauryl sulfate
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Encourage gentle brushing to avoid further irritation
These steps are particularly relevant in school and childcare settings, where mouth discomfort can affect eating and concentration.
When to Seek Medical or Dental Care
While most canker sores are harmless, professional advice is recommended if:
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A sore lasts longer than 2 weeks
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Pain is severe or worsening
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Sores occur frequently
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Eating or drinking becomes difficult
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Fever or other symptoms develop
In first aid training, persistent mouth sores are flagged as a reason for non-urgent medical follow-up, not emergency care.
Educational Disclaimer
This content is provided for general education and first aid awareness only. It is not medical advice. Persistent, severe, or recurring mouth ulcers should be assessed by a healthcare professional.