If you've never heard of black hairy tongue, that's probably a good thing. Black hairy tongue literally gets its name from its appearance: A thread-like pattern of dark "strands" found on the tongue. Although your tongue won't actually grow hair, the condition looks exactly as it sounds -- and your tongue may appear as if it's wearing a bad toupee!
A Growing Problem
This rare condition often results from either too much bacteria or yeast in your mouth. When bacteria accumulate, they settle into the small bumps on the tongue that harbor your taste buds, called papillae. The dark color is a direct result of certain types of bacteria or yeast. As these organisms weave through the papillae, they create the fuzzy appearance that resembles black or dark brown hair growing on the tongue.
Black hairy tongue is only found on the top of the tongue, and it usually starts in the back and progresses towards the tip of the tongue as it grows. Luckily, black hairy tongue is perfectly harmless and only temporary.
But as you might guess, it doesn't look pretty, and it may cause bad breath. These embarrassing factors can greatly affect one's self-esteem and lifestyle.
Information from “Hair Care” Professionals
Although no one knows what causes black hairy tongue, there are number of factors that increase your chances of developing the condition:
Antibiotics -- Antibiotics are used to kill bacterial infections. During treatment, it may also kill the "good" bacteria in your system, which controls the amount of yeast in your body. An overabundance of yeast from antibiotics is often the culprit of black hairy tongue.
Oral Hygiene -- Bad oral habits can either cause black hairy tongue or accelerate its progression when produced by other elements.
Other Medications -- Antidiarrhea agents contain a drug called bismuth subsalicylate, which helps control the fluids in your body. Like antibiotics, bismuth also alters the production of bacteria.
Smoking -- Smoking and any form of tobacco use can contribute to the growth of black hairy tongue.
Mouthwashes -- Repeated use of mouthwashes containing oxidizing agents, such as perioxide, may also modify the amount of bacteria and yeast in the mouth.
Astringents -- Personal care products that contain witch hazel and menthol are a possible source.
Caffeinated Beverages -- Drinking an excessive amount of coffee or tea has been linked to black hairy tongue.