Whitening of the tongue can occur when there is a buildup or coating of bacteria and debris on the surface of the tongue due to mild dehydration, illness (when there is less use of the tongue for talking or eating), or dryness of the mouth. A whitening of the top layer of the tongue or the presence of white spots or patches on the tongue can also be seen with infection, irritation, or chronic inflammation of the surface of the tongue. Certain oral infections, notably Candida yeast infections (known as oral thrush), are characterized by a white tongue. In contrast, some infections, like scarlet fever, can produce red spots on the tongue. Inflammation and whitening of the tongue can also occur due to dryness or environmental irritants such as smoking or other tobacco use, and may be associated with bad breath. Inflammation of the tongue is known as glossitis. Some white patches on the tongue, known as leukoplakia, can be precancerous lesions. Geographic tongue is a condition in which some areas of the tongue lack the papillae normally present on the tongue surface, resulting in irregular red patches on the tongue with a white border.