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They say that eyes are the window to the soul, but as it turns out, nails may give us a glimpse of our overall health. “Fingernails should be a healthy, pinkish color,” says Dr. Jeannette Graf, a clinical and research dermatologist and Assistant Clinical Professor of Dermatology at Mount Sinai Medical Center. “But significant changes to the entire nail could represent something going on in the body.”
Of course, slight variations are normal and no reason for panic, but here’s a guide to what specific issues could mean.
“Pitting of the nails could be psoriasis,” says Dr. Graf, adding that in some cases, it could be a symptom of a connective tissue disorder. If you see small depressions or irregular contours in your nail bed, it’s time to visit a dermatologist.
Surprisingly, the tips of your nails hold hints about your lungs. “Clubbing of the nails can be suggestive of pulmonary disease,” Dr. Graf explains. Colloquially known as Hippocratic fingers, this condition is easy to identify due to its “inflated” appearance. “If you look at the end of the nail and it’s thick and round, that’s clubbing,” Dr. Graf adds. Other signs of possible lung problems? Longitudinal, linear lesions in the nail bed.
Koilonychia—indented or concave nails with ridges—could be a sign of iron-deficiency anemia, according to Dr. Graf. It may also suggest hemochromatosis, a liver disease caused by too much iron buildup. Uneven nails, she says, should also grab your attention: “In the absence of trauma or psoriasis, when the nail is uneven, it could also be a sign of thyroid problems.”
Weak, brittle nails
“Ridges and weakness can be just dry nails,” Dr. Graf says. “The nail is made of keratin, so if you have rough and dry nails that break easily, that means they’re getting thinner.” Fortunately, treatment is easy: take 500 mcg of biotin daily, and buff your nails instead of painting them. With that said, weakened nails are sometimes a sign of nutritional deficiencies. “Selenium, biotin, and other minerals are very important,” she continues. “If you have weak nails, get a checkup to rule out anemia or thyroid issues.”
Yellow, green, or white nails
Nail polish can cause a slight yellowing of the nails, which is temporary and largely harmless. But if your nails are yellow, green, or white, that may be a sign of a serious health issue. “Yellow or green nails can be indicative of lymphatic obstruction in the fingers,” Dr. Graf says, adding that significant color changes could also be a sign of liver or kidney disease. “Basically, if your nails look funky, you’ve got to get them checked out.”
When nails turn purple or blue, says Dr. Graf, it could be a symptom of Raynaud’s. The syndrome causes blood vessels in the fingers and toes to spasm, and while it’s usually just a benign inconvenience, Raynaud’s can also be an early symptom of more serious disorders.
Those small, vertical plum lines you see running along your nails? They’re called splinter hemorrhages, and sometimes they can be chalked up to a run-of-the-mill injury. However, says Dr. Graf, it’s important to pay attention. “If you see dark, longitudinal lines, those are definitely things to get checked. They could be birthmarks, but if they go below the nail plate, they need to be evaluated for melanoma.” These tiny blood clots are also loosely associated with a host of other health issues, from lupus to heart inflammation, so schedule an appointment to rule out anything serious.