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Expert Advice

What Can Our Skin Tell Us About Our Health?

By Marianne Amoss
Mary Sheu is medical director of the Johns Hopkins Dermatology and Cosmetic Center. Her clinical interests include cosmetic dermatology; laser treatments; hyperhidrosis treatment, including Botox and miraDry; and skin cancer detection and surgery.
Your skin can give you clues about your overall health, showing signs of hypothyroidism, diabetes, cardiovascular disease, and even too many carbs. 
Not feeling well? You may see it in your skin. “There are well-established connections between internal problems and skin issues,” says dermatologist Mary Sheu, medical director of the Johns Hopkins Dermatology and Cosmetic Center at Green Spring Station. Some are quite familiar: For example, an excess of bilirubin, a waste product in our bloodstreams that is normally filtered out by the liver, causes jaundice and its characteristic yellowing of the skin. A common (and easily resolved) affliction in infants, jaundice also affects adults and can indicate conditions both benign and serious, from gallstones to pancreatitis.
Other connections are more unex-pected. One sign of hypothyroidism—an underactive thyroid gland—is hair loss along the outer third of the eyebrows. This condition has been dubbed “Queen Anne’s sign” because a portrait of Anne of Denmark, who married James I of England in 1589, shows her with short-ened eyebrows. (It was never confirmed that the queen actually suffered from a thyroid condition, but the nickname for the ailment stuck.) 
There are well-established connections between internal problems and skin issues.
New links between skin conditions and internal health have come to light in recent years. Sheu points to research that has found a connection between psoriasis and increased risk of cardiovascular disease. Psoriasis—a chronic skin condition that causes red patches of scaly skin that can be itchy or painful—has already been linked to increased risk of diabetes. In both cases, some researchers believe the inflammation that accompanies psoriasis could be the culprit, as it can affect major arteries and cause insulin resistance. “Now I routinely recommend to my patients that, if they have psoriasis, they discuss cardiovascular risk factors with their primary physician and get screened for diabetes and heart disease, and try to be in the best cardiovascular health that they can be to prevent problems later on,” says Sheu.
When it comes to taking care of skin itself, Sheu has one answer: sunscreen. It’s advice we hear constantly, but we’d do well to heed it, as a 2010 study has shown that correct sunscreen use may reduce the risk of melanoma, the deadliest kind of skin cancer. In the study, researchers followed 1,621 adults in a subtropical region of Australia for five years. About half of them applied sunscreen only when they thought it was needed, while the other half applied sunscreen daily. Ten years after the trial ended, the discretionary sunscreen group reported 22 melanomas, while the daily sun-screen group had only 11. “UVA—which is present year-round, even if there’s cloud cover—might play a larger role in skin cancer development, especially melanoma, than we had previously thought,” Sheu explains. 
To combat that, she recommends daily application of a broad-spectrum sunscreen, which protects against both UVA and UVB rays, with an SPF of 30 or higher. “If [patients] do nothing else for their skin, the one thing they can do to improve their health, to prevent skin cancer, and to improve appearance of their skin—both short- and long-term—is to wear sunscreen every day,” Sheu says. “Even if it’s overcast, I recommend that they apply it just like they would brush their teeth.”
Sun exposure doesn’t just cause skin cancer; it also causes skin to age. And so can our diet: Some researchers now say that those high-glycemic foods shunned by adherents of the “glycemic index diet”—white bread, russet potatoes, pretzels—can also age our skin.
According to one of the many theories about aging, the consumption of these high-glycemic foods is related to higher accumulation of AGEs, or advanced glycation end products, which are toxins that build up in the body over time and can cause the structural changes we see in aging skin. “These are things that we can definitely have some control over,” says Sheu. “There’s not a lot of control over our genetics, but our diet is certainly something that we can all do something about.”  
Abstract illustration of a head
Pawel Jonca

More Than Skin Deep

1. Jaundice
A yellowing of the skin caused by an excess of bilirubin, jaundice can be a sign of gallstones, pancreatitis, and other conditions.

2. Hair loss along the outer third of your eyebrows
Called “Queen Anne’s sign,” the loss of eyebrows can indicate hypothyroidism.
3. Psoriasis
Itchy or painful patches of scaly skin could mean an increased risk of diabetes or cardiovascular disease.
4. Premature aging
Too much sun exposure causes our skin to age. So might high glycemic foods. So put on your sunscreen and watch those carbs!

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