It can be disconcerting to gaze down at your clean, bare, beautiful fingernails and suddenly see white spots where there was nothing but a natural pink hue before. They’re common, but what causes those pinprick-like white spots or dots that sometimes show up on our nails, anyway? Here’s everything you need to know.

What causes white spots on nails?

Plenty of people have wondered the same thing. Fortunately, the answer is pretty straightforward for the most part. “The white spots come from changes to the protein in the keratin that make up the nail plate,” says Dr. Melissa Piliang MD, dermatologist at The Cleveland Clinic in Cleveland, Ohio. Leukonychia is the actual medical term for white spots on nails, and an injury to the nail is usually the cause, she and other experts explain. The trauma happens at the base of the nail, beneath the skin, and damages the nail very early in its growth, she explains. “Since it is the finger and not the visible nail itself that is damaged, you may not even remember injuring your nail because it may have happened many weeks before,” Dr. Piliang says.

What white spots on nails mean

An injury to the finger causes changes in the keratin layer of the nail, which is what makes the nail area become more opaque. “The opaqueness of the nail blocks out the pink color of the skin beneath the nail, called the nail bed,” says Dr. Piliang—“and the opaque area looks white while the rest of the nail looks pink.” Slamming your finger in a car door or banging it on a desk or cabinet are among the most common types of trauma to the finger. Manicures can also sometimes lead to white spots, especially if you favor acrylic nails or gel polish.

Different types of white spots

White spots from trauma can have different types of appearances: The spots can vary from tiny pinpoint dots to one large spot—or to more linear bands. These bands are a sign of previous injury, says Dr. Piliang. Certain very specific changes to the nails may indicate something more serious. Nails that are mostly white may be signs of an underlying illness such as anemia, protein deficiency, or even diseases of the liver, kidneys or heart. White lines across the nail that are parallel to the lunula—the healthy white area at the base of the fingernail—can be indicative of poisoning by a heavy metal such as arsenic, Dr. Piliang notes.

When to see a doctor

Generally speaking, “white spots on the nails are entirely harmless,” she says. “If you notice a few new spots, think back over the last few weeks to see if you can remember injuring your nail, or if you’ve had a manicure.” She also advises keeping an eye on those white spots to make sure they’re growing out along with the rest of your nail. “You would know this if the spot is moving closer to the tip of your finger,” she says. There are specific instances when seeing a doctor for white spots on your nails might be a good idea. “if you notice lots of spots appearing at once, if many nails are involved, if the spots continue to appear and/or do not appear to be growing out—then you should see a doctor.” It’s also time for a doctor’s visit “if more than half your nail turns white, especially if you do not remember injuring the nail,” Dr. Piliang advises. Very white nails can be signs of diabetes or liver disease, notes the American Academy of Dermatology Association. Use common sense as you would with any other medical condition or concern. Make an appointment with a board-certified dermatologist if you detect changes in the appearance of your fingernails—board-certified dermatologists specialize in diagnosing and treating not just the skin, but nails and hair as well. One very pleasant surprise, though: You may have read or heard that mineral deficiencies can cause white spots on the nails. This is a myth, says the Cleveland Clinic dermatologist. So don’t spend your time worrying about that! Next up, what do ridges in your fingernails mean?

Sources

Dr. Melissa Piliang MD, dermatologist at The Cleveland Clinic in Cleveland, Ohio What Are the White Spots On My Nails    What Do White Marks on Your Fingernails Mean  - 60