What causes a black tongue?
Black tongue refers to a number of conditions that cause the tongue to become unusually dark. If is has a black hairy appearance it is caused by a fungus which grows on the top surface of the tongue. Black hairy tongue is also called glossophytis. People with black hairy tongue usually complain of a bad taste in their mouth and dryness which might be resposnsible for bad breath . Black hairy tongue looks as if the tongue is coated with a black-brown stain that starts just beyond the tip but is concentrated mostly at the base of the tongue, specially around the tastebuds. The larger projections called papillae stand out in this dark area. In black hairy tongue the black color is more striking. There are number of causes for this condition including antibiotic treatment, which causes alteration in the normal flora (bacteria and fungi) which reside in the oral cavity. Stopping the antibiotic will resolve the problem. Another cause is an inapproriate diet which contains no fuits and vegetables. This usually is seen in older people. Poor general oral hygiene and the use of alcohol and tobacco is another common association. Stress and a depressive illness could also cause this condition.
Bismuth Subsalicylate containg medications like Pepto-Bismol that is used to treat nausea, heartburn , indigestion , upset stomach and diarrhea and other temporary discomforts of the stomach and GI tract can also cause a black tongue. The condition is temporary and goes away after the use of medication is stopped. There are some studies that indicates Methyldopa (blood pressure medication) and Metronidazole (antibiotic) could also cause black tongue.
