Why is there a bump or sore on the side of my tongue?

Pull your tongue to one side and look near the back edge and you will see a few soft vertical folds, a bit like the gills of a mushroom. These are foliate papillae. Cleveland Clinic describes them as rough folds of tissue on each side of the back of the tongue that contain taste buds. Small patches of lymphoid (immune) tissue sit just under them, sometimes called the lateral lingual tonsil.

Because they are near the back teeth, foliate papillae get rubbed and bitten more than most of the tongue. When that happens they can swell into a sore, red or pale lump on one or both sides. Case reports describe this as foliate papillitis and list sharp teeth and ill-fitting dentures as common sources of the trauma. Many people find the swelling for the first time during an episode like this and assume it is a growth, when the folds were there all along.

Foliate papillitis is not a separate disease so much as a description: normal tissue that has been irritated. It usually settles once the cause stops, so this page covers it together with the other reasons for a sore side of the tongue.

• Biting it. A bite while eating or during sleep leaves a tender, sometimes white or swollen spot that usually improves in a week or two.
• A sharp edge rubbing it. A chipped tooth, a broken filling, a crooked lower tooth, braces or a denture can rub the same spot every time you talk or chew. The NHS lists these as common causes of single mouth ulcers.
• Canker sores. Round, shallow ulcers with a white or yellow center and a red border. Cleveland Clinic notes they often form on or under the tongue and usually heal within two weeks. See canker sore on the tongue.
• Lie bumps. Small, painful red or white bumps from irritated papillae, often on the tip or sides. They tend to last a few days. See lie bumps.
• Linea alba. The AAFP describes a thin white line along the edges of the tongue caused by low-grade chewing trauma. It is harmless.
• Tooth marks. A wavy, scalloped edge from the tongue pressing against the teeth. This is a shape change rather than a lump.

• Irritation fibroma. A firm, smooth, pink bump that forms where tissue is bitten or rubbed over and over. DermNet lists the sides of the tongue as a common site. Fibromas do not turn into cancer, but they also do not go away on their own, so they are removed if they bother you and the tissue is checked.
• Squamous papilloma. A small growth with finger-like or cauliflower projections, linked to low-risk HPV types. It is removed and checked.
• Oral hairy leukoplakia. White, ridged or "hairy" patches on the sides of the tongue caused by Epstein-Barr virus. The AAFP notes it is linked to a weakened immune system and HIV testing may be suggested.
• Leukoplakia or erythroplakia. A white or red patch that does not wipe off. These can be precancerous and are usually biopsied.
• Tongue cancer. The AAFP notes that squamous cell carcinoma inside the mouth commonly involves the side of the tongue. Cleveland Clinic lists a lump on the side of the tongue that bleeds easily, and a red or grayish ulcer that does not go away, among the most common visible signs.

Pain is not a reliable guide. Bites and ulcers hurt a lot. Early cancer can be painless or only mildly sore, which is why the time it has been there matters more than how it feels.

• Run your tongue along your teeth on that side. If you feel a sharp spot, book a dentist visit to have it smoothed. That alone fixes many repeat sores.
• Rinse with warm salt water a few times a day to keep the area clean.
• Avoid the obvious triggers for a week: very spicy, salty or acidic foods, crunchy chips and toast, and very hot drinks.
• Ask a pharmacist about numbing gels or protective pastes for pain.
• Leave the scraper off that side. Clean the middle of the tongue gently and keep away from the sore edge until it heals.
• Take a photo and note the date. It makes it much easier to judge after 2 weeks whether the spot is shrinking.

NIDCR advises seeing a dentist or doctor for any sore, lump or thick patch in the mouth that lasts more than two weeks, and the NHS uses three weeks for mouth ulcers. Go sooner if a lump is hard, bleeds, is getting bigger, or comes with numbness or a lump in the neck.

Your risk is higher if you smoke or chew tobacco, drink heavily, or are over 40, but younger non-smokers can also be affected, so do not skip a check because you think you are low risk. A dentist can examine the spot, smooth any sharp tooth, and arrange a biopsy or referral if it does not behave like a simple sore. Some benign lumps such as fibromas also need a biopsy because they can look like other growths.