Most white or red marks inside the mouth are harmless and fade within days: a bitten cheek, a burn from hot food, a rub from a sharp tooth. Leukoplakia and erythroplakia are the exceptions that do not fade. They are patches that stay, cannot be wiped off and have no other obvious cause, and although they are not cancer, they carry a higher than usual chance of becoming cancer over time. That is why any patch that has not healed or changed within 3 weeks should be looked at by a dentist or GP.
Two names, two colours, one category
Leukoplakia is a white or grey patch that cannot be scraped away and cannot be explained by something else, such as thrush, a friction line or lichen planus. It is usually painless, which is why many people only learn about it at a check-up. Some patches are flat, thin and even in colour. Others are lumpy, wart-like, or speckled with red, and these are described as non-homogeneous.
Erythroplakia is a smooth, velvety red patch that cannot be explained by another condition. It is much less common than leukoplakia, often painless as well, and tends to turn up on the floor of the mouth, the underside of the tongue or the soft palate.
Both belong to a group called oral potentially malignant disorders. The word "potentially" is important: most people with these patches never develop cancer, but the risk is high enough that the patches are taken seriously and followed up.
Red patches carry the greater risk
A 2020 meta-analysis in Head and Neck (Iocca and colleagues), which combined 92 studies, estimated that about 9.5% of leukoplakia and about 33% of erythroplakia underwent malignant change across the follow-up periods studied. A separate 2021 review in Oral Diseases (Aguirre-Urizar and colleagues), looking only at leukoplakia studies from 2015 to 2020, reported a pooled rate of 9.8%, with individual studies ranging widely. That review found the risk was higher for non-homogeneous patches and for patches showing cell changes, called dysplasia, under the microscope.
| Leukoplakia | Erythroplakia | |
|---|---|---|
| Appearance | White or grey; flat or lumpy | Red and velvety |
| Wipes off | No | No |
| How common | The most common of these disorders | Uncommon |
| Malignant change in pooled studies | About 10% | About one in three |
| Usual next step | Remove irritants, then biopsy if it persists | Prompt biopsy |
These figures come from groups of patients followed in studies, often in hospital clinics. They describe risk across many people, not the outlook for any one patch.
Smoking and alcohol are the main drivers
Tobacco in any form is strongly linked with these patches, and heavy drinking adds to the risk, with the combination especially harmful. Chewing tobacco and betel quid are also important causes in some communities. Our articles on smoking and oral health and vaping and oral health cover how these habits affect the lining of the mouth.
Stopping smoking is worth doing for its own sake, and some white patches improve or disappear after a person quits. Not all do, so a patch still needs to be checked rather than watched at home.
What happens at the appointment
The dentist or doctor looks at the patch, notes its size, colour, texture and position, and feels the area and the neck. Anything that could be rubbing the tissue, such as a broken tooth, a sharp filling or a loose denture, is fixed first, and the patch may be reviewed again a short time later.
If a white patch is still there once irritants are removed, or if there is any red in it, a biopsy is usually recommended. A small piece of tissue is taken under local anaesthetic and examined under a microscope. This is the only way to know whether the patch shows dysplasia and how much. Depending on the case, the biopsy may be done after referral to an oral surgeon or an oral medicine service.
Treatment depends on what the biopsy shows
Patches with little or no dysplasia may be monitored with regular reviews and photographs. Patches with more marked change are often removed, surgically or with a laser, and then followed up. Even after removal, these patches can come back, and new ones can appear elsewhere, so ongoing review is a normal part of care rather than a sign that treatment failed. Cutting down on alcohol and stopping tobacco remain part of the plan throughout.
Patches that look similar
- Oral thrush is a fungal infection. The white coating usually wipes off, often leaving a red surface underneath, and it responds to antifungal treatment.
- Frictional keratosis is a white patch caused by rubbing, for example from cheek biting or a sharp tooth. It usually fades once the cause is removed.
- Lichen planus often shows as lacy white lines on both cheeks, sometimes with red or sore areas.
Telling these apart can be hard by eye, which is another reason to have a persistent patch examined rather than guessing.
Common questions
Does a white patch mean I have cancer?
No. Most white patches are harmless, and even leukoplakia is not cancer. It is a patch with a raised risk of change, which is why it is checked and often biopsied.
Should I wait to see if it goes away?
A patch that has not healed or changed within 3 weeks should be checked. A red patch, or one that is mixed red and white, is worth having seen promptly.
Is this checked at a normal check-up?
Yes. Looking at the cheeks, tongue, floor of the mouth and palate is part of a routine examination. Our guide to oral cancer screening explains what is checked.
Noticed a patch that has not gone?
If you have a white or red patch, lump or sore in your mouth that has lasted 3 weeks or more, see a dentist or GP. The team at Lumi Dental can examine it, explain what we see and arrange the next steps, including referral where a biopsy is needed. Fees depend on what is required; see our current deals page or book a general dental consultation, or get in touch through our contact page.
This article is general information and is not a substitute for individual advice. Persistent mouth changes should always be assessed by a dentist or doctor.
