Leukonychia is the medical term for white discoloration on your nails. It ranges from tiny white dots that almost everyone gets at some point to nails that turn entirely white, which can sometimes signal an underlying health problem. Most cases are harmless and caused by minor trauma to the nail, but certain patterns deserve closer attention.
How White Spots Form on Nails
Your nails grow from a root area called the nail matrix, tucked under the skin at the base of each finger or toe. When cells in the matrix are disrupted during the hardening process (keratinization), they retain tiny granules that don’t belong in a finished nail. These granules scatter light in all directions instead of letting it pass through to the pink nail bed underneath. The result: the nail looks white in that spot, for the same basic reason any surface appears white, because it reflects visible light diffusely rather than transmitting it.
Under an electron microscope, the structural fibers in the affected nail plate are fragmented, loosely packed, and irregularly aligned. That disorganization is what traps the light.
Three Types of Leukonychia
Not all nail whitening comes from the same place. The distinction matters because the cause and significance differ depending on where the white color originates.
- True leukonychia: The white color forms in the nail matrix and becomes part of the hard nail plate itself. Because the discoloration is embedded in the nail, it grows out with the nail and doesn’t disappear when you press on it.
- Apparent leukonychia: The white color comes from the nail bed, the skin underneath the nail, not the nail plate. If you press on the nail and the whiteness temporarily fades, that’s a sign the problem is in the nail bed rather than the nail itself. This type is more commonly linked to systemic health conditions.
- Pseudoleukonychia: The white discoloration sits on the surface of the nail, usually caused by a fungal infection. It can often be scraped off, which distinguishes it from the other two types.
What the Pattern Looks Like
Doctors further classify true leukonychia by how much of the nail is affected, because the pattern provides clues about the cause.
Punctate leukonychia is the most common form: small white dots scattered across one or more nails. This is the type most people notice and wonder about. It’s almost always caused by minor, everyday trauma to the nail matrix, things like bumping your finger, aggressive manicures, or nail biting. The injury happens weeks before the spot becomes visible, because the damaged section has to grow forward from the base of the nail before you can see it. Fingernails grow roughly 3 to 4 millimeters per month, so a spot near the tip of your nail may reflect something that happened two or three months ago.
Striate leukonychia shows up as white horizontal bands running across the nail. When it appears on a single nail, trauma is still the usual culprit. When it shows up across multiple nails at the same position, it suggests something systemic affected all the nail matrices at the same time, like an illness, a medication, or a toxic exposure.
Total leukonychia turns the entire nail plate white. This is rare and more likely to have a genetic basis or to reflect a serious underlying condition.
Mees’ Lines and Muehrcke’s Lines
Two specific band patterns have names because they carry clinical significance.
Mees’ lines are white horizontal bands that run across the nail and don’t fade when you press on them. They’re a form of true leukonychia caused by an insult to the nail matrix. They’re classically associated with arsenic poisoning but can also appear after other heavy metal exposures, congestive heart failure, and certain infections. Because they’re embedded in the nail plate, they move forward as the nail grows.
Muehrcke’s lines look similar at first glance, paired white horizontal bands, but they behave differently. Press on the nail and the lines disappear. That’s because they originate in the nail bed, not the nail plate. They’re a form of apparent leukonychia, typically caused by low levels of a blood protein called albumin. Muehrcke’s original study documented them in patients with albumin levels below 2.2 grams per 100 milliliters, though they’ve been reported at levels up to 2.7. The most common triggers are nephrotic syndrome, liver disease, glomerulonephritis, and malnutrition. Chemotherapy can also cause them, sometimes even when albumin levels are normal, through a mechanism that isn’t fully understood.
Terry’s Nails and Half-and-Half Nails
When the entire nail bed turns a dull, ground-glass white with only a narrow pink or brown band at the tip (typically 0.5 to 3 millimeters wide), the pattern is called Terry’s nails. The whiteness obscures the lunula, the half-moon shape at the base. Research has linked Terry’s nails not to low albumin, as you might expect, but to abnormal hormone ratios and steroid metabolism. Terry’s nails are associated with liver cirrhosis, heart failure, and diabetes.
A related pattern, sometimes called Lindsay’s nails or half-and-half nails, splits the nail more evenly: the bottom 20 to 60 percent is opaque white, while the upper portion is pink to reddish-brown. This pattern is associated with chronic kidney disease.
The Calcium and Zinc Myth
If you’ve heard that white spots on your nails mean you’re not getting enough calcium or zinc, you’re not alone. Surveys show that about half of people believe a nutrient deficiency is the cause. But there’s no scientific evidence to support this. A study published in the Journal of Human Nutrition and Dietetics specifically tested the idea and found no significant correlation between calcium intake and white spots (P = 0.681) or zinc intake and white spots (P = 0.604). Minor trauma to the nail matrix remains the most common explanation for the small white dots most people notice.
Medications That Can Cause Nail Whitening
Several chemotherapy drugs are known to trigger leukonychia, including methotrexate, cyclophosphamide, 5-fluorouracil, and etoposide. Some of these same drugs can also cause darkened nail pigmentation, so the nail changes can look different from person to person. If you’re undergoing chemotherapy and notice your nails changing color, it’s a recognized side effect rather than a separate problem.
When White Nails Deserve Attention
A few scattered white dots on one or two nails are nearly always benign and will simply grow out over a few months. You don’t need to do anything about them. The patterns that warrant a closer look share a few features: whitening that affects all or most nails, bands that appear at the same position across multiple nails, or an entire nail that turns white or develops a distinct two-tone pattern. These presentations are more likely to reflect something happening inside the body, whether that’s low albumin, liver disease, kidney problems, or a toxic exposure. The nail changes themselves don’t need treatment. They resolve when the underlying cause is addressed.
For pseudoleukonychia caused by a fungal infection, the surface chalky whiteness is typically treated with antifungal medications, either applied directly to the nail or taken orally for more stubborn cases.