Tongue Discoloration (White, Red, Purple, Blue, Yellow, Black)

Normal color of the tongue

The human tongue is a muscular organ that plays various roles in chewing, swallowing and talking. It lacks the protective skin and therefore its color is largely dependent on that tissue it is composed of in addition to the blood flowing through it. Therefore the color of the human tongue is normally a pink-red hue. The whitish coating sometimes seen on the top of the tongue varies from person to person and during different times of the day.

It is mainly due to small food particles becoming trapped within the small protrusions on the tongue known as the papillae that gives the tongue a rough surface. Furthermore bacteria and saliva act on these trapped particles thereby causing it to break down. This whitish tongue coating can easily be brushed away and is minimal in a person with good oral hygiene. The tongue has three main parts :

  • Apex – tip of the tongue.
  • Body – remainder of the visible tongue extending all the way to the back of the throat.
  • Root – attaches the tongue to the base of the mouth.

Picture from Wikimedia Commons

In some people there may be a brown to black discoloration of the tongue which occurs in patches or streaks. This may be present from birth and is usually not a cause for concern provided that it does not enlarge over time or present with other symptoms. This blackish discoloration is usually permanent and therefore cannot be removed. However, there are other causes of both a white coating and a blackish discoloration which can be a sign of some underlying disease and therefore needs to be investigated and treated accordingly.

Abnormal Colors of the Tongue

There are various colors which may present in tongue discoloration. These colors can vary greatly and each may be an indication of a specific disease or disorder in the body. Some of the colors that may be seen with tongue discoloration includes :

  • White
  • Brigh red (strawberry)
  • Purple or purple-red (magenta)
  • Blue
  • Yellow
  • Black

White tongue

White patches, streaks or lines are the most common tongue discoloration. As discussed above, a whitish coating is not uncommon and often related to poor oral hygiene.

  • Oral leukoplakia is a condition marked by a abnormal growth of the mucous membrane cells on the tongue surface. It is mainly associated with chronic irritation of the tongues with tobacco chewing and areca nut/betel leaf chewing. Tongue discoloration due to leukoplakia appears as white to gray patches on the top of the tongue and may also affect the inner cheek and gums.
  • Hairy leukoplakia is a similar condition believed to be caused by Epstein-Barr virus (EBV) infection which is more likely to arise in a person with a depressed immune system, like in HIV aids. It is largely similar in presentation to oral leukoplakia typically affecting the folds four sides of the tongue.
  • Oral thrush is a fungal infection of the mouth, usually visible on the tongue, extending down to the oesophagus. Is caused by candidiasis (yeast infection) and is more likely to occur in a person with a depressed immune system particularly in HIV/AIDS and poorly controlled long-term diabetes mellitus. The patches on the tongue appear a creamy white consistency often described as cottage cheese.
  • Oral lichen planus is a condition that occurs for unknown reasons and causes whitish lines on the inside of the mouth, including the tongue, as well as red open sores. It may affect the entire inside of the mouth and extend to the esophagus. Oral lichen planus is believed to be linked to certain infections, allergies, vaccines and certain medication.
  • Aphthous stomatitis is a condition marked by the current sores on the tongue and inside of the mouth. These are ulcers are commonly referred to as canker sores. The center of these lesions are often white to yellow in color with a red border and may eventually become open sores. Although these type of sores can occur with minor injury, recurrent cases need to be investigated further as it may be due to food allergies, autoimmune diseases, hormonal changes, infections, immune deficiency, dental prosthetics four oral hygiene products.

Two other possible causes of white discoloration of the tongue includes syphilis and geographic tongue. The latter is discussed further under bright red tongue. A temporary whitish discoloration of the tongue may also occur with a fever and dehydration. Paleness of tongue that may sometimes be mistaken for whitening can occur with conditions such as pernicious anemia (vitamin B12 deficiency) and iron-deficiency anemia.

Picture of oral thrush (candidiasis) – Wikimedia Commons

Bright Red Tongue

The normal color of the human tongue is pink to red. In some people the tongue tends to be more red than in others but this is not necessarily a discoloration of the tongue.

  • Glossitis is inflammation of the tongue that may arise for any number of reasons. The process of inflammation increases blood flow to the tongue and leads to redness, pain and swelling. The more common causes of glossitis are acute mechanical or chemical injury or infections.
  • Vitamin deficiencies as is seen with vitamin B12, niacin or folic acid may cause a strawberry red tongue.
  • Scarlet fever (scarlatina) is a condition that may sometimes develop in a person with streptococcal pharyngitis (strep throat). It presents with a red rash that covers most of the body along with a strawberry red tongue. Scarlet fever arises as a reaction to the toxin from the streptococci (bacteria) that causes the infection.
  • Geographic tongue is a condition where smooth red patches develop on the tongue with raised borders that clearly demarcate it from the rest of the tongue thereby giving the tongue a map-like appearance. The exact cause of geographic tongue is unknown but may be associated with genetic factors.
  • Toxic shock syndrome (TSS) is an uncommon condition where the toxins from certain types of bacteria, particularly Staphylococcus aureus, triggering a type of immune reaction. It should not be confused with scarlet fever. Toxic shock syndrome is potentially life threatening.
  • Kawasaki syndrome is a condition where there is inflammation of the medium and large artery walls. The exact cause is unknown but is believed to be a genetic susceptibility and possibly associated with autoimmune factors. It tends to affect boys under the age of 5 years but can occur in any age group and also affect females.

Geographic tongue from Dermatology Atlas

Courtesy of Samuel Freire da Silva, M.D.

Purple Tongue

A purple or red-purple tongue may arise with certain diseases but can also precede the development of a blue tongue. It should therefore be carefully monitored in acute cases to take note of whether more distinct blueness sets in. A purple tongue is uncommon compared to other discoloration of the tongue. It is more commonly seen with nutritional deficiencies and in particular with vitamin B2 (riboflavin) deficiency. However, it is not a common symptom in ariboflavinosis.

Blue Tongue

A bluish tongue is always considered to a be a serious sign that warrants medical attention. It is an important sign of cyanosis – a condition caused by an insufficient oxygen supply to tissue. The condition may be caused by blood disorders, diseased blood vessels, cardiac (heart) dysfunction or respiratory (lung and airway) insufficiency. This may include various conditions as discussed under the causes of cyanosis such as :

  • Acute respiratory distress
  • Airway obstruction
  • Asthmatic attacks
  • Chronic obstructive pulmonary disease (COPD)
  • Congenital heart disease
  • Pneumonia
  • Poisoning
  • Suffocation

Yellow Tongue

Yellowish discoloration of the tongue is uncommon. In most cases a yellowish discoloration precedes the development of black, hairy tongue discussed below. Another cause which rarely leads to yellowness of the tongue is jaundice although there is pronounced yellowing of the skin and whites of the eyes (sclera).

Black Tongue

A black discoloration of the tongue is rarely due to any disease. It frequently develops from birth or sometime during the course of life and tends to be permanent. However, sometimes there is a black discoloration of the tongue which may arise when the papillae become elongated giving the tongue a hairy feel.

This condition is known as black, hairy tongue. More food debris collects than normal and there is an increase in the bacteria within the mouth. It usually develops as a yellow discoloration, which progresses to a brown and then black discoloration. Causes may include :

  • Regular use of certain medication including antibiotics and bismuth-containing drugs used for indigestion.
  • Certain types of mouthwash.
  • Tobacco use.
  • Poor dental hygiene.
  • Mouth breathing.


  1. Tongue discoloration. MSD Manual

Last updated on August 13, 2018.

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