Injury: Traumatic injury is the most common cause of tongue discomfort. The tongue has many nerve endings for pain and touch and is more sensitive to pain than most other parts of the body. The tongue is frequently bitten accidentally but heals quickly. A sharp, broken filling or tooth can do considerable damage to this delicate tissue.

"Hairiness": An overgrowth of the normal projections on the top of the tongue (villi) can give it a hairy appearance. The tongue may also appear hairy after a fever, after antibiotic treatment, or when peroxide mouthwash is used too often. These "hairs" on the top of the tongue should not be confused with hairy leukoplakia. Hairy leukoplakia forms on the side of the tongue and is characteristic of AIDS.

Discoloration: The tongue's villi may become discolored if a person smokes or chews tobacco, eats certain foods, or has colored bacteria growing on the tongue.

Hairy Tongue

The top of the tongue may look black if a person takes bismuth preparations for an upset stomach. Brushing the tongue with a toothbrush or scraping it with a tongue scraper can remove such discoloration.

Iron deficiency anemia may make the tongue look pale and smooth. Pernicious anemia, which is caused by a deficiency of vitamin B₁₂, may also make the tongue look pale and smooth. The first sign of scarlet fever may be a change from the tongue's normal color to a strawberry, and then raspberry, color. A strawberry-red tongue in a young child may also be a sign of Kawasaki disease. A smooth red tongue and painful mouth may indicate pellagra, a type of malnutrition caused by a deficiency of niacin (vitamin B₃) in the diet. A red tongue may also be inflamed (glossitis)—the tongue is red, painful, and swollen.

Whitish patches, similar to those sometimes found inside the cheeks, may accompany fever, dehydration, the second stage of syphilis, thrush, lichen planus, leukoplakia, or mouth breathing.

In geographic tongue, some areas of the tongue are white or yellow and rough, whereas others are red and smooth. The areas of discoloration move around over a period of weeks to years. The condition is usually painless, and no treatment is needed.

Sores and Bumps: Sores on the tongue can be caused by allergic reactions, oral herpes simplex virus infection, canker sores, tuberculosis, bacterial infections, or early-stage syphilis. Sores can also be caused by allergies or other immune system disorders.

Although small bumps on both sides of the tongue are usually harmless, a bump on only one side may be cancerous. Unexplained red or white areas, sores, or lumps (particularly when hard) on the tongue—especially if painless—may be signs of cancer and should be examined by a doctor or dentist (see Mouth Growths: Types of Oral Cancer). Most oral cancers grow on the sides of the tongue or on the floor of the mouth. Cancer almost never appears on the top of the tongue, except when the cancer occurs after untreated syphilis.

Discomfort: Tongue discomfort can result from irritation by certain foods, especially acidic ones (for example, pineapple), or by certain ingredients in toothpaste, mouthwash, candy, or gum. Some drugs can cause tongue discomfort, as can injury and infection. A common infection causing tongue discomfort is thrush (candidiasis; see Candidiasis on Fungal Skin Infections: Candidiasis), in which an overgrowth of fungi forms a white film that covers the tongue. Intense pain of the entire mouth can be caused by burning mouth syndrome.

Usually, it is a process of elimination to find out just what is causing the discomfort. Tongue discomfort not caused by an infection is usually treated by eliminating the cause. For example, the person may try changing brands of toothpaste, discontinue irritating foods, or have a sharp or broken tooth repaired by a dentist. Warm salt-water rinses may help. Thrush can be treated with an antifungal drug, such as nystatin or fluconazole.

Burning Mouth Syndrome Burning mouth syndrome (also called oral dysesthesia) occurs most commonly among women after menopause. The most commonly affected part of the mouth is the tongue (pain in the tongue is termed glossodynia). A painful burning sensation may affect the entire mouth (particularly the tongue, lips, and roof of the mouth [palate]) or just the tongue. The sensation may be continuous or intermittent and may gradually increase throughout the day. Symptoms that commonly accompany the burning sensation include a dry mouth, thirst, and altered taste. Possible consequences include changes in eating habits, irritability, depression, and avoidance of other people. Burning mouth syndrome is not the same as the temporary discomfort that many people experience after eating irritating or acidic foods. Burning mouth syndrome is poorly understood. It probably represents a number of different conditions with different causes but a common symptom. A common cause is the use of antibiotics, which alters the balance of bacteria in the mouth, leading to an overgrowth of the fungus Candida (a condition called thrush). Ill-fitting dentures and allergies to dental materials may be causes as well. Overuse of mouth rinses and sprays may lead to burning tongue syndrome, as can anything that leads to a dry mouth, such as alcohol or tobacco use, and many medications. Sensitivities to certain foods and food additives, particularly sorbic acid and benzoic acid (which are food preservatives), propylene glycol (found as a moisturizing agent in foods, drugs, and cosmetics), chicle (found in some chewing gums), and cinnamon, may play some role. Deficiencies of vitamins, including B12, folic acid, and B-complex, can cause burning mouth syndrome. Iron deficiency has also been implicated. The condition is easy for doctors to diagnose but difficult to treat. Frequent drinks of water or use of chewing gum may help keep the mouth moist. Antidepressants, such as nortriptyline, or antianxiety drugs, such as clonazepam, are sometimes helpful, although these drugs may make the symptoms worse by causing dry mouth. Sometimes symptoms disappear without treatment but may return later.

Last full review/revision October 2006 by Robert B. Cohen, DMD