What can skin teach about body: healthy or not?

Our skin is the body's largest organ, and one of the most complex, containing sweat glands, blood vessels and nerve endings, among other features.

It forms a crucial protective barrier between the external environment and our internal organs. It protects us against pathogens and chemicals, while also serving to regulate our temperature.

It also acts as a sensory organ, stores water and fat, and helps to produce vitamin D when exposed to the sun.

But the skin can also be a window into our overall health, Shari Lipner, an associate professor of clinical dermatology, and director of the Nail Division, at Weill Cornell Medicine, told Newsweek.

Anthony Rossi, an American Academy of Dermatology board-certified dermatologist, told Newsweek there are "so many things" that our skin can tell us about an individual.

Changes to the skin can be an indicator of several medical conditions or underlying diseases, although most skin disorders are not signs of serious illness.

If the skin takes on a yellow appearance or the whites of the eyes become yellow, this is often a sign that the individual has elevated levels of liver enzymes or bilirubin, which can indicate a problem with the hepatobiliary system—the liver, gall bladder and bile ducts—such as jaundice, according to Rossi.

Similarly, if the palms become a deep yellow colour or your skin turns yellowish-orange, this may be a sign of excessive beta-carotene ingestion. Excessive consumption of foods that are rich in this substance—such as carrots, squash and sweet potatoes—or beta-carotene supplements, can cause a condition known as carotenemia, which is characterized by these symptoms.

What can a person's skin reveal about them?

The skin can reveal a variety of clues about a person's lifestyle and behaviours. A dermatologist can look at how tanned someone is or look for signs of sun damage to gauge how much outdoor exposure that individual has had.

People who smoke will also often notice changes in their skin. Smokers may have discolouration of the skin on their fingers, while dark spots can appear on the face. This habit can also cause the skin to age and wrinkle prematurely, Lipner said.

Smoking has been shown to damage the repair mechanisms in the skin. It also affects fibrous substances known as collagen and elastin, which provide strength, support and elasticity. Smokers tend to have fewer collagen and elastin fibres, which can lead to the skin becoming slack, hardened and less elastic, according to a 2019 study.

The skin may also exhibit giveaways that an individual may not be getting enough sleep.

"Droopy, saggy, dark circles under the eyes can be a clue to fatigue," Steven Daveluy, a dermatologist with the Wayne State University School of Medicine, said in a blog post for the American Academy of Dermatology.

What should healthy skin look like?

According to Rossi, healthy skin comes in many forms. But there are some general signs that people can look out for. "You want your skin to look well hydrated, not dry or cracked, good elasticity and without spontaneous bruising," he said.

"We all have different skin tones so bruising and rashes look differently on different skin types."

Relatively consistent skin colour or even pigmentation all over the skin can be a sign that the organ is healthy, Lipner said.