This photo of Miley Cyrus is causing a commotion. For once, it's got nothing to do with her outfit.

Image: Miley inadvertently matches her tongue to her outfit (via Getty).

It’s not uncommon for Miley Cyrus‘ on-stage antics and bold costumes to make headlines — but you know you’ve really made it as a celebrity when your tongue alone is capable of generating attention.

Yesterday, Elle US shared a link on Facebook about the singer’s hosting gig at the MTV Video Music Awards, illustrated with the photo above. The first thing commenters jumped on wasn’t Cyrus’ visible nipples, or the content of the article itself, but the colour of her tongue.

“Miley, please brush your tongue,” the first comment reads. “She needs to brush that nasty tongue or go get checked out… your tongue is never supposed to be white” another says.

So, if Cyrus’ tongue could talk (well, it technically can, but you know what I mean), what would it say about her health? Is a white tongue normal?

According to Dr Piraveen Pirakalathanan, Principal Medical Officer of health website Health&, your tongue’s appearance is an important marker of both your oral and general health.

A healthy, normal tongue is pink in colour — although the underside is normally a little redder — moist, and covered in grooves and small bumps. “The appearance can be affected by numerous things, including vitamin deficiencies, dehydration, infections, or allergic reactions. It can also be a consequence of certain medications, especially antibiotics, and also smoking,” Dr Pirakalathanan explains.

In most cases, these changes will be transient. “A short-lived change in appearance is usually due to bad oral or dental hygiene, in the fact you haven’t brushed your tongue or your mouth properly,” Dr Pirakalathanan says. (Post continues after gallery.)

He explains it’s important to brush your tongue, not just your teeth and gums, because it houses half of the bacteria in your mouth. Dr Pirakalathanan says brushing your tongue with toothpaste is recommended, but scraping it with a spoon or a specially-designed tongue scraper is preferable.

Professor David Manton of Melbourne Dental School and the Australian Dental Association, adds that tongue cleaning is often a cultural practice, and is more common in India and Asia than in Australia. “The cleaner will remove food particles and some microorganisms from the surface of the tongue. This may improve our overall oral health, however there is limited scientific research to support this,” he says.

If you notice a change in the appearance of your tongue that doesn’t resolve itself, it could be symptomatic of an underlying health condition.

1. White coating or spots

Dr Pirakalathanan says a white coating or spots could be a result of oral thrush, also known as a candida infection, which is more common among people with weakened immune systems, the elderly (especially if they wear dentures), and diabetics. People who use steroid medications, such as inhalers for asthma and lung conditions or antibiotics, are also susceptible to it as they can affect the bacterial balance in the mouth.

"There is also the possibility of white, streaky patches that relate to a condition called lichen planus, another immune-related condition," says Professor Manton.

A white appearance could also indicate a condition known as leukoplakia, which is "basically an excessive growth of cells that lie on the tongue and give it its white appearance," Dr Pirakalathanan says. This is commonly seen in smokers and is thought to be pre-cancerous if not treated.

Professor Manton says persistent white or red areas on the tongue may be a precursor to an oral cancer. "Risk factors are smoking, drinking alcohol and HPV infection," he says.

2. A red tongue

If you believe Disney cartoons, we all walk around with tongues the colour of raspberries. In reality, though, it can be a sign of something else going on in your body... unless you've just eaten a red icy pole, of course.

Vitamin deficiencies, most commonly B12 and folic acid, can make your tongue look redder than usual.

It could also be a sign of geographic tongue — yes, this is a real thing. "This gets its name from a map-like pattern that forms on the tongue, where there are red spots and lines that resemble a map or an atlas," Dr Pirakalathanan explains.

Professor Manton says geographic tongue may be related to discomfort with acidic foods like tomatoes, or spicy foods. "Sometimes a candida infection can also cause a red area towards the middle of the tongue," he adds.

In children especially, a red tongue can also result from more serious conditions like scarlet fever or Kawasaki disease. These are usually accompanied by other medical symptoms, such as fever and unwellness, and require medical attention.

3. A black tongue

If your tongue looks black and has a furry or even 'hairy' sensation, there could be an overgrowth of bacteria in your mouth. Dr Pirakalathanan says this is generally symptomatic of poor oral hygiene, but can also be caused by antibiotics or chemotherapy agents.

4. Sores

A painful tongue, or one covered in sores, can be a sign of underlying health conditions if it doesn't self-heal.

"It's quite common that people accidentally bite or scald their tongue on hot food, however these symptoms usually clear up within six weeks. If they continue, then evaluation by a doctor or dentist is usually recommended," Dr Pirakalathanan says.

In circumstances where there's a burning sensation on the tongue, Dr Manton says iron deficiency, or anaemia, has been associated with this.

5. Dry tongue

Dr Pirakalathanan says a case of desert mouth can indicate dehydration, or a side-effect of medications or conditions that impact the salivary glands.

If you experience any of these symptoms and find they linger for a few weeks, seeing your doctor or dentist is recommended. Generally speaking, drinking lots of water, maintaining a balanced diet and cutting back on smoking can help to keep your tongue healthy and happy.

Have you ever experienced one of these symptoms?