7 Things Your Nails Can Reveal About Your Health

Updated: Nov. 20, 2020

Changes to the shape, color, and texture of your nails are sometimes a sign of something serious.

woman looking at her finger nails
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You could have a circulatory problem

Suddenly swollen skin at the end of your fingers with nails that are bulbous—meaning the nail is shaped like an upside-down spoon—is a reason to have your hands and feet checked out. Nail clubbing can be a benign hereditary condition or a sign of  something more serious, like infection, inflammation, or lung or heart disease. But if you have swollen skin because you can’t stop biting your nails, try these six tricks for how to stop biting nails.

doctor's hands holding a patient's hand

You could have melanoma

“Pigmented bands in the nail are common and usually normal especially in people with darker complexions,” says Dana Stern, MD, assistant clinical professor of dermatology at Mt. Sinai School of Medicine. However, she notes that dark bands or stripes could also be a sign of cancer. Most people think melanoma starts in the skin, but it can also begin under the nail, specifically in the thumb, index finger and big toe nail. Keep an eye out for a single brown or black band and if there is a brownish pigment to the skin surrounding the nail. It’s hard to determine if a dark band is benign or something more serious, so head to a dermatologist for an evaluation if you notice something new. It’s important to take care of your nails to stay aware of any changes in pigment. Start by learning the everyday habits you didn’t realize were ruining your nails.

test tubes with liquid; dropper putting red fluid into one test tube

You could be anemic

When your nail bed is concave—imagine a droplet of water resting on the nail plate without rolling off—you have a condition known as koilonychia, or “spoon-shaped nails.” The condition is usually caused by an iron deficiency. If you notice your nails are concave, ask your doctor to run blood work to check for anemia, notes Dr. Stern. Learn some other secrets your hands can reveal about your health.

woman looking at her hair in alarm

You could have an inflammatory disease

Nail pitting, which looks like tiny little dents along the surface of the nail, is associated with psoriasis, says Dr. Stern. The condition is also a symptom of alopecia areata, a disease marked by hair loss.

close up of manicured nails

You could have thyroid issues

Brittle nails that peel or split can be caused by certain medical conditions like an underactive thyroid, Raynaud’s disease, and a protein deficiency. “If someone always had great nails and suddenly they are peeling or breaking excessively, check blood work including thyroid hormones,” says Dr. Stern. If you can rule out thyroid issues, check out these simple tips that’ll help give you healthier nails.

female doctor discussing diagnosis with female patient

You could have metal poisoning

Most white lines on the nail are normal or may have been caused by trauma—think banging or crushing the fingernail. However, white lines or strips that run across your nail bed can in rare cases be more serious. This is a telltale sign of Mees’ lines, a condition caused by arsenic or poisoning by other heavy metals. Dr. Stern advises a full medical evaluation if you notice the condition. White crescents on the nail can also be a side effect of chemotherapy.

woman with extravagant manicured nails

You’re milking your manicure for too long

If your nails are yellow, it’s usually caused by having nail polish on for an extended period of time and is no reason to worry, according to Dr. Stern. Take the polish off to let your nails breathe. The yellowing should be gone within a few days. If the yellowing is prolonged, check in with a doctor to rule out a fungal infection. Make a visit to your favorite nail salon, but first, find out the secrets your manicurist isn’t telling you.