Why Do I Have White Spots on My Nails?

Every now and again you might notice some white spots on your nails. But what can cause these to appear and is it anything to be worried about?

While they may look unsightly, white spots on finger nails are very common and, more often than not, nothing to be concerned about, experts told Newsweek.

However, in some rare cases, these white spots might be a sign of an underlying condition that may require you to seek medical advice or attention.

What Are the Causes of White Spots on Nails?

According to American Academy of Dermatology board-certified dermatologist
Chris Adigun, there are several causes of white spots on nails—few of which are problematic.

"For whatever reason, many people think they are due to some kind of vitamin deficiency—which is not true," she told Newsweek. "The most common causes are trauma to the nail as it is being developed—so a small bang to the end of your finger, in the region before you reach your nail, can lead to a small white spot in the nail as it grows out. That is because the matrix lies beneath this skin, and it is the delicate apparatus in charge of building the nail."

"In addition, trauma to the nail itself can leave a white spot. This is known technically as punctate leukonychia. The problem is that the trauma often precedes the white spot by weeks to even over a month, so most people forget about the trauma by the time they see the spot," Adigun said.

Another factor that can cause white spots include prolonged use of nail polish, which can cause small white areas to form on the surface of the nail known as keratin granulomas. These form due to the partial breakdown of the surface of the nail plate.

Some fungal infections can also result in white spots on the nail surface that are powdery in consistency, according to Adigun.

"This is due to the fungus digesting the nail material of the superficial portion of the nail plate, and is known as superficial white onychomycosis."

Two other less common causes for white marks on the nails are Beau's Lines and Mees' Lines.

Beau's Lines arise due to an abrupt halt in the production of the nail plate. While they more often occur in the form of indentations, they may sometimes appear white. These marks can be caused by trauma, illness, severe stress and chemotherapy, among other factors.

Mees' Lines, meanwhile, are white bands that form across the nails due to poisoning or exposure to arsenic or other heavy metals.

"Heavy metal or arsenic exposure is very serious," Adigun said. "But the lion's share of white spots on the nails are completely benign."

Shari Lipner, an associate professor of clinical dermatology, and director of the Nail Division, at Weill Cornell Medicine, told Newsweek that in some rare cases a serious condition such as underlying kidney, heart or liver disease could cause white spots.

When Should You See a Doctor About White Spots on the Nails?

If the white spots only appear temporarily, they are more than likely nothing to worry about. But if they persist—and you don't think they could be related to an injury—or they seem to grow or spread, you might want to visit a health care professional to determine what the potential cause could be.

"An easy test to tell if you may have a serious condition is to press on the nails," Lipner said. "If the white color remains, it is usually due to trauma and is not concerning. If you press on the nail and the white color disappears, this may be the sign of a more serious health condition. A board-certified dermatologist can examine your nails and diagnose your condition."

Correction 05/27/22, 11:40 a.m. ET: This article was updated to correct a pronoun.