Hairy tongue is an uncommon, benign condition that is also known as black hairy tongue or lingua nigra. It is characterized by abnormal elongation and blackish or dark brownish discoloration or "staining" of the thread-like elevations (filiform papillae) that cover most of the tongue's surface (dorsum linguae). Such changes often begin at the back (posterior) region of the top of the tongue and extend toward the front (anterior) of the tongue's surface but never involve the undersurface.
The specific underlying cause of hairy tongue is unknown. However, possible predisposing factors may include poor oral hygiene and overgrowth of pigment-producing bacteria or fungi in the mouth, treatment with certain antibiotic medications, smoking, chewing tobacco, and/or mouthwash use.
Hairy tongue is characterized by elongation and overgrowth (hyperplasia) of the filiform papillae into “hair-like” projections and the development of a dark brown or black coating on the surface of the tongue. Such changes typically occur in a triangular region in front of the circumvallate papillae, which are the largest papillae of the tongue. (These nodular elevations, which typically range from eight to 12 in number, are arranged in the form of a “V”.) As noted above, the back region of the top of the tongue may initially be affected with subsequent extension toward the front.
Many individuals with hairy tongue have no associated symptoms (asymptomatic). However, some with the condition may be affected by nausea, gagging, altered taste, bad breath (halitosis), and/or other associated symptoms.
In some cases, hairy tongue may spontaneously disappear. In addition, it typically subsides with appropriate oral hygiene and the elimination of other predisposing factors. (For more information, please see the “Standard Therapies” section below.)
Hairy tongue is thought to result from failure of the normal “shedding” (desquamation) of the outermost layer of the filiform papillae, overgrowth of certain pigment-producing bacteria or fungi normally present in the mouth, and an abnormal accumulation of pigment residues, keratin, or other debris in the region. (Keratin is a fibrous protein that is a primary component of the outermost layer of the skin, nails, and hair.) Although the specific underlying cause of hairy tongue remains unknown, several potential predisposing factors have been implicated. Such factors include treatment with certain antibiotic medications (e.g., tetracycline therapy, which may lead to overgrowth of certain fungi); the use of particular oral bismuth-containing medications; the use of mouthwashes; smoking; chewing tobacco; excessive alcohol consumption; and/or poor oral hygiene. Hairy tongue is not infectious nor does it lead to oral cancer.
In males or females with hairy tongue, the age of onset is variable. Hairy tongue most commonly affects adults; however, it may sometimes occur during childhood or adolescence. It is not an inherited disease.
In individuals with suspected hairy tongue, receiving a thorough evaluation by physicians, dentists, and/or oral surgeons is important to exclude other underlying conditions and to confirm a diagnosis of hairy tongue. Recommended treatment measures typically include removing potential predisposing factors, such as stopping smoking, discontinuing antibiotic therapy if possible and receiving proper alternative treatments as necessary under a physician's direction, and/or other appropriate steps. In addition, affected individuals should speak with their dental specialists for guidance concerning appropriate measures to improve oral hygiene in their particular case. Such measures typically include using a soft-bristled toothbrush to regularly cleanse the tongue.
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In some individuals with hairy tongue, the administration of certain topical agents (keratolytic agents), such as urea or tretinoin (a derivative of vitamin A), may be recommended to decrease filiform overgrowth by promoting proper “shedding” (desquamation) of the outermost layer of the papillae. Further research is needed to determine the long-term safety and effectiveness of such therapies for hairy tongue.
Beers MH, et al., eds. The Merck Manual. 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:754.
Fauci AS, et al., eds. Harrison’s Principles of Internal Medicine. 14th ed. New York, NY: McGraw-Hill Companies, Inc.; 1998:189-90.
Behrman RE, et al., eds. Nelson Textbook of Pediatrics. 15th ed. Philadelphia, PA: W.B. Saunders Company; 1996:1049, 1889.
Wyngaarden JB, et al., eds. Cecil Textbook of Medicine. 19th ed. Philadelphia, PA: W.B. Saunders Company; 1992:2325.
Heymann WR. Psychotropic agent-induced black hairy tongue. Cutis. 2000;66:25-26.
Mirbod SM, et al. Tobacco-associated lesions of the oral cavity: Part I. Nonmalignant lesions. J Can Dent Assoc. 2000;66:252-56.
Manabe M, et al. Architectural organization of filiform papillae in normal and black hairy tongue epithelium: dissection of differentiation pathways in a complex human epithelium according to their patterns of keratin expression. Arch Dermatol. 1999;135:177-81.
Langtry JA, et al. Topical tretinoin: a new treatment for black hairy tongue (lingua villosa nigra). Clin Exp Dermatol. 1992;17:163-64.
Naidenova M. Some epidemiological and clinical-etiological studies on children with lingua nigra villosa. Stomatologiia (Sofiia). 1989;71:11-15.