Linezolid-induced black hairy tongue.

Black hairy tongue (BHT) is a self-limiting disorder characterized by abnormal hypertrophy and elongation of filiform papillae on the surface of the tongue. The exact mechanism of drug-induced BHT is unknown. Several factors have been implicated and included smoking or chewing tobacco, drinking alcohol, poor oral hygiene and antibiotics such as tetracyclines and penicillins.