Drug-Induced Black Hairy Tongue

Dennis F. Thompson, Pharm.D. FASHP, FCCP; Tiffany L. Kessler, Pharm.D.


Pharmacotherapy. 2010;30(6):585-593. 

In This Article


Black hairy tongue is an uncommon, benign, self-limiting disorder characterized by abnormally hypertrophied and elongated filiform papillae on the surface of the tongue. Although classically described as having a black discoloration, the disorder can manifest with other colorations of the tongue. The prevalence of BHT is highly variable, and a variety of factors can contribute to this disorder. The highly variable prevalence rate along with fairly commonplace predisposing factors make causality assessment in this disorder quite difficult.

Strong quantitative evidence from case reports indicates that antibiotics are associated with BHT. The unusual dosage forms used in the older literature, such as oral penicillin lozenges and penicillin aerosol, makes interpretation of these data difficult. The qualitative evidence (Naranjo scores) for antibiotics is not significantly different from that of the other miscellaneous drugs reported to cause BHT. Drugs capable of inducing xerostomia are the other class of drugs implicated in BHT. The presence of predisposing factors, however, also clouds the interpretation of this evidence. Reasonable mechanisms exist for theorizing antibiotics and xerostomic drugs in the causality of BHT.

Intervention in patients with drug-induced BHT involves excellent oral hygiene, discontinuing any predisposing factors or drugs, and possible additional therapy for cases that do not respond to more conservative therapy. Clinicians should be aware of the prevalence, predisposing factors, drug classes that may play a role the development, and treatment of BHT.


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