White hairy tongue

The back of the tongue (above), in front of the herringbone groove, is the densest area of ​​the filamentous nipple of the tongue. Stimulated by various factors, the stratum corneum at the tip of the filamentous nipple does not fall off, but instead grows into a tuft-like change, forming a hairy tongue. Normal filamentous nipples are white thorn-shaped protrusions, many in number, slender and pointed, about 0.5 to 3 mm. The epithelium at the tip of the nipple can be keratinized. When the keratinized epithelial cells fall off, mixed with some bacteria, food residues, saliva, etc., there are different thicknesses and different colors on the surface of the tongue, that is, tongue coating. The surface of the tongue coating is discolored. The color is darker near the center, and it can be black, yellow, green, and white.