The white spots on your nails aren't from a vitamin deficiency. 6 other possible causes

Having a white spot on your nails is one of the most common — and commonly misunderstood — nail issues. For instance, contrary to popular belief and countless internet rumors, white spots on nails aren't usually due to a vitamin deficiency.

"I can't tell you how often I have patients who come in and say, 'Oh, calcium deficiency,'" Dr. Shari Lipner, an associate professor of clinical dermatology at the Weill Cornell Medical Center, tells TODAY.com. "But that's really a myth," she says.

When trying to figure out the true cause of your white spots, the first clue to look for is whether you just have a lone spot or if a whole chunk of your nail is tinted white, Dr. Kristen Lo Sicco, associate professor at the Ronald O. Perelman Department of Dermatology at NYU Grossman School of Medicine, tells TODAY.com.

A white spot on nails here and there may be due to a more minor issue whereas a white film over part of the nail might signal a fungal infection.

From there, you can perform a simple test on your own: If you press on the affected nail and the white area is still visible, that's called true leukonychia, Lo Sicco says, which is more often related to external factors, like aggressive nail filing.

But if the white area goes away while you press on the nail, then you're likely dealing with pseudo-leukonychia, which indicates "the nail bed skin is impacted underneath," Lo Sicco explains. That can be a sign of something more serious and even some underlying health conditions.

Causes and treatments for white spots on nails

Trauma

"The most common cause of a white spot is trauma," Lipner says. And, when trauma is the culprit, it's often from manicuring. Filing, gel manicures and cutting and pushing cuticles can all cause white spots on nails, she explains.

But, if there's repetitive trauma like that to the nail, "there will likely be multiple nail changes," Lo Sicco says. If someone is repeatedly buffing the nail too aggressively, for instance, that will thin out the nail plate and make splitting more likely. "So you might have somebody with some white marks, but also have some splitting," she explains.

Treatment: White spots due to trauma will grow out and resolve with time. But you should also take care to dial back on whatever behavior was the original cause. Avoid aggressive filing, and don't get your cuticles pushed back or cut, Lipner advises.

Fungal infection

Most of the time, fungal infections cause yellow-tinted nails, Lipner says. "But, once in a while, it can be a very superficial type of fungus that leaves this kind of white little film on the nail," she says.

Treatment: Fungal infections require a trip to the dermatologist. They'll first take a sample of the nail to test it for the presence of fungus and, if there is an infection, they'll prescribe an antifungal medication to take care of the issue.

Keratin granulations

These dry, white areas of nail are "thought to occur as a result of leaving your nail polish on for too long," Lo Sicco says. Essentially, these develop when the nail is "not exfoliating properly from the nail polish being left on for a longer period of time," she explains.

If you've left reddish nail polish on for a while, you might see yellow coloring, she explains. But keratin granulations can appear after using any color of polish.

Treatment: For small, superficial keratin granulations, you can either leave them alone to resolve on their own or try to gently file them away, Lo Sicco says. But it's important to be careful when doing this yourself and not be too aggressive with your nails, she adds.

If you find you get these repeatedly after wearing nail polish, try leaving polish on for a shorter amount of time, Lo Sicco says, or even taking a break from polish for a few weeks.

Onycholysis

This condition occurs when the nail begins to lift away from the nail bed, which might leave a white spot along the edge of your nail where it's separated, Lo Sicco says.

Onycholysis can arise due to an injury, fungal infection or nail psoriasis. And, depending on the cause, it can also come with pain and yellow nail discoloration.

Treatment: The best treatment for onycholysis depends on what's causing it. If the condition is due to trauma or injury, it will likely resolve as the nail grows out. And keeping your nail care and manicures gentle will help prevent it from happening again.

However, if your onycholysis is caused by a fungal infection, you'll need to get medication for the underlying infection.

Arsenic poisoning

Rarely, arsenic poisoning can be a cause of white spots on the nails, Lipner says. If heavy metal poisoning with arsenic or thallium is to blame, the white spots typically appear as horizontal bands along the entire width of the nail, which are known as Mees' lines.

Heavy metal poisoning can cause many other symptoms, including gastrointestinal issues, sore throat and skin pigmentation changes, the Cleveland Clinic explains.

Treatment: Arsenic poisoning can happen quickly if you're exposed to one large dose, or it can develop over time by eating or drinking contaminated items or inhaling contaminated air. If you suspect you have arsenic poisoning, you should contact a health care provider immediately.

Underlying health conditions

"There are some conditions where either half or 80% of the nail looks white, and that can be due to a systemic disease, such as kidney disease and liver cirrhosis," Lipner explains. Sometimes low iron can cause white spots, she adds.

If your doctor or dermatologist suspects an underlying condition might be causing the white spots on your nails, they'll likely have you undergo more systemic testing to see what's going on.

The right treatment will depend on the specific health issue that's causing the white nails.

When to see a doctor

Some causes of white nails may be easier to identify and manage on your own, like aggressive filing or leaving nail polish on for too long.

Letting white spots go away on their own can be a slow process. Know that it can take six months for a fingernail and a year or more for a toenail to completely grow out.

But if you're not sure what's causing the white spots on your nails, if the issue isn't improving with time, or if you notice other nail issues — lifting, splitting, swelling, pitting (small depressions), pain — it's best to get checked out by an expert. And if you notice a change in your nails after a specific event or injury, that's another sign it's time to check with an expert.

"If there's any concern and something isn't going away, it's best to make an appointment to see a board-certified dermatologist so that they can evaluate and do their exam," Lo Sicco says.

This article was originally published on TODAY.com