Canker sores in the mouth: causes, symptoms and treatment
What are canker sores?
Canker sores (aphthae) are painful, inflammatory ulcers of the oral mucosa. They typically appear as round or oval spots with a whitish-yellow coating and a reddened border. They usually develop on the inside of the lips and cheeks, on the edge or underside of the tongue and on the floor of the mouth. Canker sores are not contagious. Small canker sores usually heal on their own within 7 to 14 days.
- Canker sores – also known as recurrent aphthous stomatitis when they keep coming back – are shallow, painful ulcers of the oral mucosa
- They appear as round or oval spots with a whitish-yellow coating and a reddened border
- Typical sites are the inside of the lips and cheeks, the edge and underside of the tongue and the floor of the mouth
- Small canker sores usually heal on their own within 7 to 14 days
- Low-level laser treatment, also known as photobiomodulation, can relieve pain and support healing. Whether it makes sense in your individual case is something we clarify after the examination
- Canker sores are not contagious and are not a viral disease
Canker sores are localised, inflammatory lesions of the mucosa. Their exact cause has not been fully clarified. Immunological processes and various contributing factors probably interact.
Canker sores can occur individually or in groups and keep recurring in some people.
Canker sores or herpes: what is the difference?
At first glance, canker sores and herpes blisters look similar. However, they differ significantly in cause, appearance and course. The following table compares the most important characteristics:
| Characteristic | Canker Sores | Cold sores (lip herpes) |
|---|---|---|
| Appearance | Whitish-yellowish depression with a reddish border, sunken | Groups of small blisters, later crusts |
| Location | Mostly the movable oral mucosa: inside of the lips and cheeks, edge or underside of the tongue, floor of the mouth and soft palate | Mostly the lip margin or outside of the lip; recurrent herpes inside the mouth tends to affect the hard palate or the attached gums |
| Contagious? | Not contagious | Contagious (herpes virus) |
| Cause | Exact cause unclear; possible triggers and accompanying factors are local irritation, stress, genetic predisposition and iron, folic acid or vitamin B12 deficiency | Herpes simplex virus type 1 (HSV-1), reactivation |
| Healing time | 7 – 14 days (minor), up to 6 weeks (major) | 7 – 10 days |
| Course | No preliminary stage (blisters), visible directly as an ulcer | Tingling and a feeling of tension before the blisters |
| Recurrence | Possible, without a pathogen permanently in the body | Yes, the virus remains permanently in the nerve tissue |
| Treatment | Pain relief, gels, home remedies, professional dental treatment | Antiviral creams (aciclovir), no scratching |
Symptoms and types of canker sores
- Burning or tingling as a warning sign, one to two days before the sore becomes visible
- Whitish-yellow, slightly sunken spot with a reddened border
- Severe pain when eating, speaking and brushing teeth
- Usually only a few millimetres in size; in rare cases up to three centimetres
- Minor aphthae usually heal within 7 to 14 days without scarring. Major aphthae can persist for several weeks and leave scars
Canker sores can announce themselves with a slight tingling or burning sensation at the affected site. Only after one to two days does the actual ulcer become visible. The typical picture shows a shallow, round or oval spot with a whitish-yellow fibrin coating and a reddened border.
The pain is characteristically intense. It gets worse on contact with acidic, spicy or coarse foods and when brushing teeth in the affected area. Typical locations are the inside of the lips and cheeks, the edges of the tongue and the gums. Ulcers of this kind develop less frequently on the palate.
The three types of canker sores are minor, major and herpetiform aphthae. For most of those affected, it remains the harmless minor form. Major aphthae as well as unusually frequent, pronounced or long-lasting symptoms should be assessed by a dentist or doctor, as deficiencies or underlying diseases may be involved in some cases.
Medically, the three types are distinguished by size, frequency and healing time:
Smaller than 1 cm, typically 3 – 5 mm. Heal in 7 – 14 days without scarring. Occur individually or in small groups. Account for by far the largest share of all cases.
Larger than 1 cm, sometimes up to 3 cm. Very painful, take several weeks to heal. Can leave scar tissue. Rarer, but considerably more distressing.
Many pinhead-sized ulcers at the same time (up to 100). Despite the name, no viral involvement. Subside after 1 – 2 weeks, but come back.
Would you like to have your canker sores checked?
Have your symptoms lasted longer than two weeks, do they recur frequently or are they particularly painful? Then we will examine your oral mucosa and advise you on suitable treatment options.
Causes and triggers: why do canker sores develop?
- Psychological strain and stress can promote the occurrence of canker sores.
- Mechanical irritation such as braces, sharp tooth edges or accidentally biting the inside of the cheek can trigger canker sores.
- A family predisposition can increase the risk of recurrent canker sores.
- A deficiency in iron, folic acid or vitamin B12 can be associated with recurrent canker sores.
- Hormonal changes are discussed as a possible influencing factor; however, the connection has not been clearly established.
The exact cause of canker sores has not been conclusively clarified. Immunological processes and various contributing factors probably interact. In some people, stress can promote the development of new canker sores, but it is not the cause in all those affected.
Frequently asked questions about canker sores (FAQ)
No, canker sores are not contagious and are not transmitted by kissing or by sharing crockery. Their exact cause has not been fully clarified. Viruses or bacteria are not considered a direct cause of typical canker sores.
Small minor aphthae heal completely and without scarring after 7 to 14 days. Larger major aphthae take several weeks and can occasionally leave slight scars. Herpetiform aphthae subside after 10 to 14 days, but come back.
Canker sores are not contagious and typically occur on the movable oral mucosa, for example on the inside of the lips and cheeks, on the underside of the tongue or on the floor of the mouth. Herpes is caused by herpes simplex viruses and is contagious. Cold sores usually form clustered blisters on the edge of the lip. Recurrent herpes inside the mouth tends to affect the hard palate or the attached gums. A reliable distinction is not always possible on the basis of appearance alone.
With recurrent canker sores, factors such as stress, local irritation, a family predisposition or deficiencies can play a role. Some underlying diseases can also be accompanied by canker-sore-like changes in the oral mucosa. A dental or medical assessment is advisable if the sores are unusually large or painful, persist for longer than two weeks, occur very frequently or are accompanied by other symptoms.
For short-term pain relief, protective gels or local anaesthetic preparations may be suitable. Irritating, very acidic or spicy foods should be avoided temporarily. Depending on the findings, low-level laser treatment can relieve symptoms and support healing. In the case of severe, frequently recurring symptoms or those lasting longer than two weeks, a dental or medical assessment is advisable.
Canker sores that keep coming back or are particularly painful? We will take a calm look at them.
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