Causes of coated tongue vary. The difference in the tongue coating appearance can help narrow down the causes and treatments.
The tongue appears to have a thick, white coating due to inflammation and trapped particles, such as dead cells and bacteria. The causes of a white tongue coating are varied. Usually, white tongue poses little concern and may be caused by dehydration, mouth breathing, medications, alcohol use, smoking, or fever.
Some more serious conditions also cause the symptom, including the following: leukoplakia, which can be an early sign of cancer; syphilis, a sexually transmitted infection; trush, a yeast infection of the mouth; an autoimmune disease called oral lichen planus.
To treat this form of coated tongue, brush or scrape your tongue. Drinking extra water may help if dehydration is a cause. You can prevent white tongue through eliminating excessive alcohol consumption, quitting smoking, breathing through your nose, and practicing good oral hygiene. If the coating lasts longer than two weeks or is accompanied by other symptoms such as pain or swelling, seek medical care.
The human tongue ‘sheds’ off layers. When the papillae (projections on the tongue) grow longer without shedding, the tongue looks hairy. Often this coated tongue condition appears worse because discoloration occurs. Bacteria and organisms can cause the tongue to appear brown.
Hairy tongue has several possible causes. The most likely and least worrisome include coffee drinking, food dyes, tobacco use, overuse of astringent or oxidizing mouth rinses, bismuth medications, and antibiotic use. The more serious potential causes of hairy tongue include AIDS, radiation exposure, and chronic medical conditions. Improved oral hygiene can help prevent hairy tongue.
Stopping the use of tobacco, astringent mouth rinses and certain medications might help. If nothing improves the condition, seek medical advice. Specific antibiotics may help.
Some causes of coated tongue may cause the tongue to appear yellow. Similar to white tongue and hairy tongue, this happens when inflammation occurs and bacteria and debris become trapped. The non-threatening yellow tongue causes are similar to white tongue, most being easy to treat with better oral hygiene practices, breathing through the nose, and ceasing alcohol and tobacco use.
Coated tongue can have other causes, however, that require medical treatment. Tuberculosis, HIV infection, typhoid, gastro-esophageal reflux disease, indigestion, malabsorption syndrome and liver or gallbladder problems can all cause yellow tongue.
If the symptom does not improve with thorough mouth cleaning and changes in habits, go to a doctor. You also should see a medical care provider if any other symptoms accompany coated tongue, such as yellowing of the eyes, fever, chronic cough, heartburn, or indigestion.
MayoClinic.com: White Tongue
MedlinePlus: Tongue Problems
MayoClinic.com: Black, Hairy Tongue
Causes of Coated Tongue
MayoClinic.com: Yellow Tongue