The Scary Thing Your Nails Could Be Telling You About Your Health

The next time you find yourself casually glancing down at your fingertips, contemplating your next manicure, stop and take a second to find out what's happening underneath your nail polish. Your body often sends you clues that something might not be right health-wise, and your nails are no exception. Changes in nail shape, texture, and color could mean you should schedule an appointment with your doctor, not your nail tech. We asked dermatologist Debra Jaliman, the author of Skin Rules, about the most common nail abnormalities and what they could be telling you about your health.

Yellow nails: Yes, discoloration is sometimes just the stain left behind by a dark nail or a side effect of smoking cigarettes (gross). But it can also indicate a fungal infection or diabetes. If your symptoms also include the thickening of the nail plate and slowed growth, a respiratory disease, like bronchitis, might also be to blame.

Nail clubbing: Sorry, this doesn't mean hopping from nail salon to nail salon 'til the wee hours of the morning. Nail clubbing is an increase of tissue around the fingertips where the nail curves, causing the nail bed to become rounded and angled. Most often it is caused by low oxygen in the blood, indicating lung disease. It's also associated with inflammatory bowel disease, cardiovascular disease, AIDS, and liver disease.

Spoon nails: Like the name suggests, this is when your nails are concave in shape (like a spoon). It's typically a sign of anemia (iron deficiency), which can be treated with supplements or by adjusting your diet. But other possible causes include liver disease, heart disease, and hypothyroidism.

Soft or brittle nails: This can result from overuse of acetone and nail polish remover, which dries out the nail plate. Frequent dish-washing and swimming can also dehydrate nails. Try a nail-strengthening treatment or cuticle cream, and be sure to wear rubber gloves while performing household chores.

Beau's lines: Most indentations or ridges that are horizontal across the nail plate are caused by an infection or an injury, says Jaliman. They can also be caused by malnutrition or a reaction to a drug, such as chemotherapy treatments.

Vertical nail ridges: If, however, the ridges go up the length of your nail, you don't have to worry—these often develop with age. "It's the wrinkles on your nails, just like you get wrinkles on your face," explains Jaliman. We know: Not exactly a fun concept, but it's nothing to be alarmed about. And hey, Essie makes a good ridge-filling basecoat.

Terry's nails: This condition can be identified by nails that appear mostly white except for a narrow band of pink at the tips (kind of like a reverse pseudo French manicure). If you're suffering from this, head to your doctor ASAP. It's often a sign of liver disease, congestive heart failure, kidney failure, or diabetes.

Nail pitting: Small depressions in the shape of dots appear on the nail surface of up to 50 percent of people with psoriasis. It can also occur in people with alopecia areata, an autoimmune disease that causes hair loss.

Onycholysis: Listen up, manicure lovers: This condition is often caused by excessive manicuring or a reaction to the use of nail hardeners and glues (like those in acrylics and gels). It causes your fingernails to separate from the nail bed, along with a change in color to opaque white, green, or even yellow. More seriously, it is sometimes associated with thyroid disease, psoriasis, injury, and infection.

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