Symptoms of a coated tongue

Updated November 21, 2016

An essentially harmless condition, coated tongue, can be caused by damaging the surface of the skin with hot beverages or food, or can be triggered by the use of tobacco products. The symptoms of a coated tongue are not painful or dangerous.

The Facts

A coated or a hairy tongue is a condition that affects adult men and women. For the most part, it is harmless, causing more embarrassment than anything else. Everyone's tongue produces keratin. It acts as a form of protection for the top of the tongue. When the tongue produces keratin faster than it is worn away, this leads to a build up of keratin on the top of the tongue. This is the cause of coated tongue. Symptoms include a striking white coat on the top of the tongue, a brown or yellow coat, bad breath and hair on the tongue.

White Coating

The first symptom that alerts most people that they have coated tongue is a bright white coating on the top of the tongue. This white coating can cover the entire tongue from the back to the tip. The white coating is built up keratin accumulating on the surface of the tongue. It is not painful, but it is strange looking and can alarm the patient who sees it for the first time.

Darker Coating

Sometime a person with a coated tongue looks in the mirror and does not see a white coating. Instead, she sees a yellow or brown coating on her tongue. This is a symptom of coated tongue in which keratin build up has been inundated by naturally occurring bacteria in the mouth. The bacteria have a yellow or brown pigment that colours the keratin. The bacteria are not harmful and neither is this symptom of coated tongue.

Bad Breath

Some people with coated tongue experience bad breath as a symptom. This is caused by food particles and bacteria getting caught in the keratin build up on the tongue. Those particles and bacteria also can cause a foul taste in the mouth. This symptom, although socially inconvenient, also is harmless.


If someone who has coated tongue experiences an even heavier build up of keratin, then he might experience the symptom of a hairy tongue. The keratin accumulates on the taste buds in a way that makes the tongue look as though it is covered in fur or hair. Hairy tongue is a more severe case of coated tongue. It can be a more upsetting sight than a coated tongue, but it is still a harmless condition.

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