You know your fingernails like the back of your hand (ha), so changes may catch you off guard. White spots on nails can be as small as dots or as large as the entire nail: Leukonychia is the medical term for white spots on the nails, and it is classified into two types. There are two types of leukonychia:
- true leukonychia (spots on the nail plate itself)
- apparent leukonychia (spots that appear to be on the nail but are actually on the nail bed skin underneath).
And there is a simple test you can perform right now to determine whether the spots are serious.
What exactly do “true” white spots on nails imply?
White spots on nails are usually just a sign of trauma. When you accidentally bang your nail on a cabinet, the nail-making tissue under your skin is disrupted, according to Chris G Adigun, MD, FAAD, a board-certified dermatologist in Chapel Hill, North Carolina. Because nails take a long time to grow, you’ll most likely have forgotten about the bump by the time you notice spots. “By the time you notice any kind of change in your nails, the event that caused it has already occurred months before,” explains Dr. Adigun.
True leukonychia can also be a sign of arsenic or other heavy metal poisoning, which can cause parallel white bands known as Mees lines. But those were more common when people drank contaminated well water; nowadays, most true leukonychia is benign, according to Ivy Lee, MD, a dermatologist in Pasadena, California, and assistant clinical professor of dermatology at UCLA. However, if you notice this specific fingernail mark, which could be a sign of cancer, you should contact your doctor right away.
What exactly do “apparent” white spots on nails imply?
Terry’s nails, which appear almost completely white, and Lindsay’s nails, which are sometimes called half-and-half nails because they are white on the bottom and reddish or brown on the top, are two common types of visible leukonychia. Both are linked to serious health issues such as kidney, liver, or heart problems. The diseases wreak havoc on the veins in the fingertips, causing the nail to appear whiter.
Press on the nail to determine if the white spots on your nails are caused by leukonychia. If the white spot remains, it is on the nail itself—this is damage to the nail and is generally not a cause for concern. However, if the whiteness disappears or changes color, it is caused by the skin of the nail bed and may indicate a more serious health problem. “That’s a fantastic quick and easy test,” Dr. Lee says.
But don’t panic if you’re healthy and your nails have turned white—that won’t be the first symptom of a serious disease. According to Dr. Lee, dermatologists will typically look for Terry’s or Lindsay’s nails as a diagnostic clue for someone who is already in the ER with more concerning symptoms. If you’re more concerned about the texture of your nails, learn why ridges in the fingernails can indicate disease.
Could white spots on your nails indicate something else?
Some fungi can also cause the nails to appear white, but they are not the same as leukonychia. They, like true leukonychia, will not go away when pressed, but they have their own characteristics. They will feel powdery, and “you can almost scrape it out of the fingernail,” according to Dr. Adigun. In that case, consult your doctor about an antifungal treatment to restore normalcy to your nails. Keep an eye out for these other signs that your fingernails are telling you about your health.