Every now and then you might notice that your tongue---usually a healthy pink---is coated in white. While a white tongue is generally a sign that something is off-kilter in your body, there's no need to worry. Most of the time, the cause of white tongue is harmless and easily remedied. In rare cases, however, it can be a sign of serious disease or illness.
The surface of the tongue is covered with finger-like projections called papillae. If your tongue is entirely coated in white, you most likely have an inflammation of the papillae. The white appearance is caused by dead bacteria, debris and dead cells becoming stuck among the papillae. Smoking, excessive mouth breathing and poor oral hygiene can cause the papillae to become inflamed. This type of white tongue can be treated by brushing your tongue or using a tongue scraper, quitting smoking, drinking more water or eating more fibre, which helps to scrape the debris from your tongue.
If your tongue is white in thick, cottage cheese-like patches, you might have oral thrush. Oral thrush is a kind of yeast infection (Candida albicans), and most often is seen in infants, the elderly, diabetics, drug abusers, people with immune deficiencies and asthmatics being treated with inhaled steroids. Use of antibiotics or chemotherapy can also result in oral thrush. The treatment for oral thrush varies depending on the underlying cause but is generally treated with oral antifungal medication.
White patches on the tongue (and mouth) may also be cause by a condition called leukoplakia. In this instance, the cells in the mouth grow excessively, causing the white patches. Leukoplakia is commonly seen in smokers and users of other tobacco products. The condition is usually harmless, but sometimes oral cancer forms in the areas where leukoplakia appears, and the patches themselves might also harbour cancer. Usually, quitting use of the tobacco products will clear up the condition, but if not, a doctor might use a scalpel or razor to remove the patches. Even then, a person should be vigilant about the reappearance of the patches because of the heightened risk of oral cancer.
Oral Lichen Planus
If your tongue has a lacy appearance or many raised white lines, you are likely to have oral lichen planus. While no one knows for certain the cause of oral lichen planus, there have been some links to patients having an autoimmune condition. In general, there is no treatment and the condition will likely go away on its own (though often it is chronic and will reappear eventually).
If your white tongue is accompanied by pain, a loss of feeling inside your mouth or sores that don't heal after several days, you should consult a medical professional. Certain symptoms accompanying a white tongue can be a sign of oral cancer or other serious illnesses.