Although a white tongue can cause concern, it is usually harmless, according to the Mayo Clinic. It can usually be alleviated by using a tongue scraper and drinking an adequate amount of water. In some cases, a white, coated tongue can signify a serious illness, such as an infection or a precancerous condition. A physician or dentist should evaluate a white tongue that causes concern, lasts for more than two weeks or is painful.
Thrush
Thrush is an infection caused by an accumulation of the fungus Candida albicans in the mouth, according to the Mayo Clinic. It can cause creamy white lesions on the tongue, inner cheeks, gums, roof of the mouth and throat. Thrush and other yeast infections occur when the immune system is suppressed due to illnesses such as diabetes, cancer or HIV/AIDS or drugs such as prednisone, and antibiotic treatment.
Precancerous Lesions
Leukoplakia is a thickened, white patch on the tongue or elsewhere in the mouth that develops slowly and can't be scraped off. Leukoplakia is a precancerous lesion that results from inflammation caused by tobacco use, especially chewing tobacco, and rough patches on dental work that irritate the mouth. Precancerous lesions may progress into cancer if not treated. If biopsy results indicate the lesion is precancerous, surgical removal is necessary.
Inflammation and Debris
A white tongue is usually caused by inflammation of the projections on the surface of the tongue. Debris, dead cells and bacteria build up on the projections and cause the white, coated appearance. Dry mouth is the most common cause and can result from smoking, dehydration, alcohol use, fever, mouth breathing and some medications.
Selenium Overdose
A coated tongue can result from long-term exposure to high doses of selenium. Selenium is a mineral required by the body that occurs naturally in certain foods. It is also found in nutritional supplements and in some industrial settings. Selenium is toxic in high doses and can result in liver damage, liver cancer and death. In addition to a coated tongue, other signs of long-term exposure include garlic odor on the breath, metallic taste in the mouth, pale skin and nervousness, according to the Centers for Disease Control and Prevention.
Hairy Leukoplakia
Hairy leukoplakia is thought to result from of continual Epstein-Barr virus infection that often occurs in patients with HIV/AIDS and other disorders that cause immune system suppression. It is characterized by a white thickening on the borders of the tongue, sometimes with hairlike projections, notes the American Academy of Family Physicians. According to Medline Plus, it may be the first sign of HIV infection and can also occur after a bone marrow transplant or other event that weakens the immune system.
