Black Hairy Tongue

Image on right from Wikipedia.

For a relatively rare condition, black hairy tongue has received quite the national attention from CNN to the New York Post after a case report was published in the New England Journal of Medicine on 9/6/18.

Normally the dorsal surface of the tongue mucosa is covered by filiform papillae protrusions that typically rise less than 1mm from the surface. However, in black hairy tongue, these normally very short tongue protrusions can grow to over 1 cm in length and 2mm width.

This carpet of abnormally long filiform papillae protrusions then secondarily collect fungi, bacteria, and inorganic particles which leads to the discoloration and the appearance of black hairy tongue. To reiterate, micro-organisms found in black hairy tongue is coincidental and not causative. I will further stress that although fungi and bacteria may be present and do contribute to the discoloration, there is no "infection" present per se. These organisms are happily just living on the surface without actually invading the tongue lining.

Treatment (if pursued) is really to address the long filiform papillae and not so much what's on it.

To read more about black hairy tongue and what is done for treatment (if pursued), click here.

Source:
Black 'hair' on your tongue? Here's what that could be. CNN 9/5/18

Reference:
Black Hairy Tongue. N Engl J Med 2018; 379:e16. Sept 2018