White tongue fur

The clinical significance of a white tongue fur is fourfold.

• Clean, moist, thin white fur is normal and healthybut may also appear at the onset of sickness indicating that the evil has not yet entered the interior and right qì remains undamaged.
• Glossy white fur indicates cold. If thin, it indicates external wind-cold or interior cold; if thick, it indicates cold-damp or cold-phlegm.
• Dry white fur indicates transformation of cold evil into heat. An extremely dry thin white fur indicates insufficiency of fluids. A thick dry white fur indicates transformation of dampness into dryness. A mealy white fur with a red tongue body indicates dampness trapping hidden heat, which is treated by first transforming the dampness to allow the heat to escape rather than with excessive use of cool medicinals.
• Thick slimy white fur indicates phlegm-damp and is usually accompanied by a slimy sensation in the mouth, oppression in the chest, and torpid intake. White fur occurs in a variety of diseases. A thick white fur is mainly associated with hypertrophy of the corneal layer of the filiform papillae for unknown reasons. A white mold-like coating covering the tongue and the whole surface of the oral cavity, sometimes with small patches of mucosal erosion known as erosion speckles, is termed oral putrefaction.
A loose, crumblike fur is called a bean curd tongue fur (tofu fur). These signs indicate the development of sweltering damp-heat in patterns of stomach vacuity and damage to yīn. This generally occurs in enduring or serious illnesses and indicates complex patterns that are difficult to treat.