People are being urged to look out for red-flag signs that could mean something more sinister
People who have a mouth ulcer or have had one in the past are being issued a stark health warning. Mouth ulcers, sometimes referred to as canker sores or aphthous ulcers, are common and most are harmless. They can be painful lesions or sores that develop on the soft tissues of the mouth, including the roof of the mouth, inner cheeks, lips, tongue, and gums.
Usually round or oval in shape, they have a red, inflamed border and a white, yellow, or grey centre. They are usually harmless, non-contagious, and typically resolve on their own within one to two weeks.
However, a dentist has issued a ‘don’t ignore’ warning as he says they could be an early warning sign of cancer if they last longer than they should. The warning comes as cases of oral and throat cancers continue to rise across the UK.
Cold weather, low immunity and stress can make ulcers more common in winter, but any sore that lasts longer than two weeks should never be ignored, says Dr Andrej Bozic, DMD, MDM, oral surgeon at Dentum.
“Most ulcers are harmless and clear within a week or two,” he explained. “But if one persists, bleeds, or keeps coming back in the same spot, it’s a red flag that shouldn’t be dismissed.”
Why lingering ulcers can be dangerous
Persistent sores can occasionally indicate early oral or throat cancer, especially in those who smoke, drink frequently, or have HPV (human papillomavirus). However, the majority of mouth ulcers are caused by stress, friction, or biting the cheek unintentionally.
In the UK, these cancers are becoming more common. The Oral Health Foundation reports that while HPV-related throat cancers are currently among the fastest-growing cancer types, particularly in men, mouth cancer cases have doubled over the past 20 years
Dr Bozic said: “These cancers often start small and painless. You might not feel unwell, so the temptation is to wait and see if it heals. But catching it early makes all the difference.”
He says early tissue changes, such as white or red patches, non-healing ulcers, or thickened areas inside the mouth, are frequently first noticed by dentists and oral surgeons.
The warning signs to look for
According to Dr Bozic, anyone should seek a check-up right away if they notice:
- A mouth ulcer that lasts longer than two weeks
- A lump, patch or sore spot that keeps recurring in the same area
- Pain or difficulty swallowing
- A lump in the neck or under the jaw
“If you notice any of these symptoms, don’t wait for it to hurt,” he advised. “Early detection gives the best chance of full recovery.”
Simple steps to stay safe
Dr Bozic says keeping up with regular six-monthly dental check-ups is one of the easiest ways to ensure early detection of serious conditions. “Your dentist isn’t only checking for cavities,” he said. “We’re also trained to spot early signs of cancer, infections and other diseases that may first appear inside the mouth.”
He also recommends maintaining good oral hygiene, avoiding tobacco and limiting alcohol – both major risk factors for oral and throat cancers – and ensuring HPV vaccination for young people. “Most ulcers are nothing to worry about,” Dr Bozic added. “But if one refuses to heal, don’t wait. Getting it checked could save your life.”
According to the NHS, a pharmacist can recommend a treatment to speed up healing, prevent infection or reduce pain, such as:
- antimicrobial mouthwash
- a painkilling tablet, mouthwash, gel or spray
- corticosteroid lozenges
- a salt (saline) mouthwash
It adds: “Mouth ulcers are rarely a sign of anything serious, but may be uncomfortable to live with. They need time to heal and there’s no quick fix… Mouth ulcers are common and should clear up on their own within a week or two. But see a GP or dentist if you have a mouth ulcer that lasts longer than three weeks.”
What causes mouth ulcers?
Most single mouth ulcers are caused by things you can try to avoid, such as:
- biting the inside of your cheek
- badly fitting dentures, braces, rough fillings or a sharp tooth
- cuts or burns while eating or drinking – for example, hard food or hot drinks
- a food intolerance or allergy
- damaging your gums with a toothbrush or irritating toothpaste
- feeling tired, stressed or anxious
Sometimes they’re triggered by things you cannot always control, such as:
- hormonal changes – such as during pregnancy
- your genes – some families get mouth ulcers more often
- a vitamin deficiency, such as iron, zinc, folic acid, vitamin B or vitamin D
- medicines – including some NSAIDs, beta blockers or nicorandil
- stopping smoking – people may develop mouth ulcers when they first stop smoking
If you have several mouth ulcers, it can be a symptom of:
- hand, foot and mouth disease, which also causes a rash on the hands and feet
- oral lichen planus, which causes a white, lacy pattern inside the cheeks
- Crohn’s disease and coeliac disease (conditions that affect the digestive system)
- a weakened immune system from having a condition like HIV or lupus
