Diseases that may cause the tongue to be white include oral thrush, syphilis, mouth cancer and HIV/AIDS, according to Mayo Clinic. Other diseases that may cause a white tongue include leukoplakia, tongue cancer, oral lichen planus and geographic tongue. Using certain medications may cause an oral yeast infection. Some people experience a white tongue after an extended period of taking antibiotics.
White tongue occurs when the papillae on the tongue's surface swell and become overgrown, notes Mayo Clinic. When the papillae are enlarged, dead cells, bacteria and other materials become stuck between the papillae, causing a white appearance.
Causes of white tongue include a fever, alcohol consumption, breathing through the mouth and dehydration, states Mayo Clinic. Poor oral hygiene or dry mouth can result in a white tongue as can eating mostly soft or mashed foods. Sharp tooth edges or dental devices can irritate the tongue, causing it to become white.
Treatment for white tongue includes drinking plenty of water and using a toothbrush or tongue scraper to remove it, recommends Mayo Clinic. White tongue is usually harmless, but it may be a good idea to see a doctor if the white tongue lasts for a few weeks, if it is painful, or if the changes to the tongue are causing concern.