White Patches in the Mouth: Leukoplakia, Lichen Planus and Thrush

By the team at Bollington Dental Practice, under the clinical direction of Dr Ellie Burrows, Principal Dentist. Updated October 2026.

Most people find a white patch in their mouth by accident: brushing their teeth, catching sight of it in the mirror, or running a tongue over something that feels slightly different. An online search can then make an ordinary patch feel frightening. The reassuring truth is that most white patches have everyday explanations, from a bitten cheek to a bout of thrush. A few do need a proper look, and the simplest dividing line is time.

The short answer

White patches in the mouth have several common causes. Oral thrush usually appears as creamy white patches that can be wiped off, often leaving a red area underneath, and a pharmacist can usually help. Leukoplakia is a white patch that cannot be wiped or scraped away, does not usually hurt, and needs assessing by a dentist or GP, because a small number of cases can change over time. Oral lichen planus often shows as a lacy, web-like pattern of fine white lines, most often inside both cheeks. Whatever you think a patch might be, any patch lasting three weeks or more should be checked, and every examination at Bollington Dental Practice includes a mouth cancer screen.

Thrush: the white patch that wipes off

Oral thrush is an overgrowth of candida, a yeast that lives harmlessly in most mouths until something tips the balance. It typically looks like creamy white or yellowish patches on the tongue, inside the cheeks, on the roof of the mouth or at the back of the throat. The key feature is that the patches can usually be wiped away, sometimes leaving a red, sore or slightly bleeding surface. Some people notice a cotton-wool feeling, a bad taste, loss of taste, or cracks at the corners of the mouth, which we cover in our guide to angular cheilitis.

What makes thrush more likely. A recent course of antibiotics, using a steroid inhaler, wearing dentures (especially overnight), dry mouth, smoking, diabetes and a weakened immune system all make thrush more likely. Babies get it too, and it is common in the first few months.

What helps. For adults, a pharmacist can usually recommend an antifungal gel or other treatment. Tell them about any other medicines you take, particularly blood thinners such as warfarin, because some antifungal treatments interact with them. Babies with thrush should be seen by a pharmacist, health visitor or GP, who will advise on what is suitable for their age. If you use a steroid inhaler, rinse your mouth with water after each dose. If you wear dentures, clean them carefully every day and leave them out overnight. See your GP if thrush has not improved after a week or so of treatment, or if it keeps coming back, because recurring thrush can point to something else, such as diabetes, worth checking.

Leukoplakia: the white patch that does not wipe off

Leukoplakia is the name for a white patch in the mouth that cannot be rubbed or scraped off and does not have another obvious explanation. It does not usually hurt and may be smooth, wrinkled or slightly raised. It most often appears on the inside of the cheeks, the gums, the tongue or the floor of the mouth, and it is more common in older adults and in people who smoke or use other forms of tobacco. Heavy drinking can also play a part.

Most leukoplakia is harmless, and many patches stay the same for years. The reason it is taken seriously is that a small number of patches can develop changes in their cells over time, and in some cases leukoplakia can be an early sign of mouth cancer or develop into it. That is a reason to have it looked at, not a reason to panic.

What assessment involves. Your dentist will look closely at the patch, feel the area and the glands in your neck, and ask about smoking, alcohol, medicines and anything that might be rubbing, such as a sharp tooth or a denture. If there is a possible cause, they may remove it and review the patch a couple of weeks later to see whether it has faded. A white patch with no clear cause is usually referred to a hospital oral medicine or oral and maxillofacial team, who may take a small sample (a biopsy) under local anaesthetic so the cells can be examined.

What happens next. Depending on the result, management may mean regular monitoring, removing the patch, or both. Whatever the outcome, stopping smoking and cutting down on alcohol are the most useful things you can do yourself. Free NHS stop smoking support is available.

A red patch, or a patch that is speckled red and white, is less common than a plain white one but carries a higher chance of significant change, so it should be checked promptly rather than watched.

Lichen planus: the lacy pattern

Oral lichen planus is a long-term inflammatory condition that affects the lining of the mouth. Its classic appearance is a lacy, web-like network of fine white lines, usually on the inside of both cheeks, though it can also affect the tongue and gums. Some people have no symptoms at all and only find out at a check-up. Others have red, sore areas or shallow ulcers, a burning feeling, or discomfort with spicy, acidic or very hot food. It can come and go in flare-ups over many years.

Lichen planus is not contagious and is not caused by anything you have done. Its exact cause is not fully understood, but it is thought to involve the immune system. It can also affect the skin, nails and other areas, so mention any rash or other symptoms to your GP. Sometimes a very similar pattern is a reaction to a medicine or to a filling sitting right next to the patch, which is one reason your dentist will ask about your medicines and look at the teeth nearby.

Managing it. There is no cure, but symptoms can usually be kept under control. Many people find it helps to avoid foods and drinks that trigger soreness, to use a mild toothpaste (some people find a toothpaste without sodium lauryl sulphate gentler), and to keep teeth and gums as clean as possible. For painful flare-ups, your dentist, GP or hospital team may prescribe a steroid mouthwash, spray or gel. Because people with oral lichen planus have a slightly increased risk of mouth cancer, regular check-ups are important, and any area that changes, thickens or forms an ulcer that does not heal should be looked at.

Other everyday causes

Friction and biting. A thin white line along the inside of the cheek at the level where your teeth meet is very common and harmless. Habitual cheek or lip biting can leave rough, shaggy white patches. A sharp tooth, a broken filling or a denture edge can rub a white area into the gum or tongue. These usually fade within a couple of weeks once the cause is removed.

Burns. Very hot food, or holding a tablet such as aspirin against the gum to ease toothache, can burn the lining of the mouth and leave a white, peeling patch. Painkillers should always be swallowed, never held against the gum. Burns usually heal within a week or two.

Ulcers. Ordinary mouth ulcers often have a white or yellow centre with a red border, and most heal within one to two weeks. Our mouth ulcers guide covers them in detail.

White coatings on the tongue are a slightly different subject, and our guide to white tongue and geographic tongue explains what usually causes them.

When to get a white patch checked

• Any patch lasting three weeks or more. Any white or red patch, lump or ulcer in the mouth that has not gone within three weeks needs checking by a dentist or GP.
• Sooner if it is red or speckled, thickened, hard, growing or bleeding, or if you also notice numbness, a lump in the neck, difficulty swallowing, or a tooth that has become loose for no clear reason. Our guide to mouth cancer signs explains these in more detail.
• If you are unwell. If your mouth is so sore you cannot eat or drink, or you feel generally unwell, contact your GP or call NHS 111.

Every examination at Bollington Dental Practice includes a mouth cancer screen, in which your dentist checks your lips, cheeks, gums, tongue, the floor and roof of your mouth, and feels the glands in your neck. If anything needs a closer look, they will explain what they have seen and, where appropriate, refer you urgently to the hospital. A new patient examination is £89 including X-rays, and an examination for existing patients is £60. Our dental plan, from £15.95 a month, includes an annual examination with mouth cancer screening.

Frequently asked questions

Is leukoplakia cancer?

Usually not. Most leukoplakia is not cancer, and many patches stay the same for years. A small number can develop changes in their cells over time, which is why patches are assessed, sometimes with a small biopsy, and then monitored. Stopping smoking and cutting down on alcohol are the most useful things you can do yourself.

How can I tell if a white patch is thrush?

Thrush usually looks like creamy white patches that can be wiped away, often leaving a red or sore area underneath, and it is more likely after antibiotics, with a steroid inhaler or with dentures. A pharmacist can advise. A white patch that cannot be wiped away is not typical of thrush and should be checked by a dentist or GP.

Is oral lichen planus contagious?

No. Oral lichen planus cannot be passed to other people through kissing, sharing cups or any other contact. It is a long-term inflammatory condition thought to involve the immune system. It can usually be managed by avoiding triggers, keeping the mouth clean and, for flare-ups, prescribed treatment, with regular check-ups.

How long should I wait before getting a white patch checked?

No longer than three weeks. Any patch, lump or ulcer that has not gone in that time needs checking by a dentist or GP. Get it seen sooner if it is red or speckled, growing, hard, bleeding or painful, or if you smoke or drink heavily.

Noticed a patch?

If you have a white patch that has not cleared, or you would simply like the peace of mind of a thorough check, call us on 01625 574609. New patient examinations are £89 including X-rays and include a mouth cancer screen, and every price is published on our fees page.

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