“Forget about calcium deficiency”: What white spots on your nails really mean, according to a dermatologist
You’ve noticed small, light-colored marks on your nails and are wondering what they really mean. White spots on the nails are a common topic, surrounded by many misconceptions. Dr. Ines Zaraa, a dermatologist and venereologist in Paris, provides clear answers about their actual causes and when it’s best to see a doctor.
White Spots on Nails: What the Experts Really Say
These marks have a specific medical name: leukonychia. They can appear as white spots of various sizes or as white streaks on the nail. According to Dr. Zaraa, they are generally benign.
However, a common misconception has been around for a long time: that these spots are a sign of a calcium or iron deficiency. That’s not true. Deficiencies can cause nails to appear ridged, spoon-shaped, or softer and more brittle, but they do not cause white spots, the dermatologist explains. So there’s no need to rush out and buy dietary supplements.
Furthermore, localized leukonychia does not indicate a serious illness. This clarification is reassuring for anyone who becomes concerned when they notice these small marks appearing in their daily lives.
Microtrauma, the leading cause of light-colored marks
The most common cause of white spots on the nails is microtrauma. It occurs particularly at the nail root—the white crescent visible beneath the folds of skin—as the specialist explains.
These minor injuries may seem insignificant in everyday life. For example, a pedicure that’s a little too rough or a pair of shoes that’s too tight in the toes is enough to cause this type of injury.
“Nail cells normally become transparent as they keratinize and lose their nuclei, allowing light to pass through them. When certain cells retain their nucleus or exhibit abnormal keratinization—due to microtrauma, for example—they scatter light more and appear white.” — Dr. Ines Zaraa
A second possible cause is nail dehydration. Regular nail polish left on too long, or semi-permanent nail polish, dries out the surface and can give it a whitish, grainy appearance, adds Dr. Zaraa.
In some cases, these light-colored marks may also indicate a medical condition. These can include superficial fungal infections or inflammatory conditions such as psoriasis, which causes small white spots on the nail. In much rarer cases, leukonychia may be a sign of lichen or alopecia areata.
- Shoes that are too tight in the toe area
- Injuries During Pedicures or Manicures
- Trimming Cuticles
- Any direct pressure on the nail
- Regular or semi-permanent nail polish left on too long
When White Spots on Your Nails Should Be a Cause for Concern
Caution is warranted when there is no obvious cause. If the marks cannot be explained by prolonged use of nail polish, ill-fitting shoes, or known microtrauma, a visit to a dermatologist is recommended. In addition, a specific family history is also a warning sign.
According to figures from the French National Health Insurance , nearly one-third of psoriasis cases have a family history of the condition. Psoriasis also affects the skin and scalp: the presence of other lesions in these areas makes it even more important to seek medical attention promptly. If a single finger is affected for no apparent reason, Dr. Zaraa recommends seeing a dermatologist as soon as possible.
An even more serious sign warrants attention: a uniformly white or milky-colored fingernail may be a sign of liver or kidney disease. In this case, you should see a doctor right away.
White Spots on the Nails and Psoriasis: Signs to Watch For
Psoriasis is a chronic inflammatory condition of the skin and hair that can also affect the nails. It occurs in people with a specific genetic predisposition, which is why a family history of the condition is a warning sign that should be taken seriously.
On the other hand, if the whitish marks on the nails are accompanied by patches on the skin or a scaly scalp, the clinical presentation clearly points to nail psoriasis. In this case, only a dermatologist can make a reliable diagnosis.
Treatments and preventive measures based on the cause
Treatment depends directly on the cause of the spots. In the case of microtrauma, no special care is needed. You simply need to be patient: it takes 4 to 6 months for a fingernail to grow back completely, and 9 to 12 months for a toenail, explains Dr. Zaraa.
To prevent dryness, a few simple habits are all it takes to protect the nail surface. Take breaks between applying nail polish, choose acetone-free products, avoid soaking your hands in water, and don’t cut your cuticles. Similarly, avoid wearing shoes that put strain on your feet on a daily basis.
In cases of inflammatory conditions, a topical treatment suitable for psoriasis is prescribed, most often in the form of corticosteroid-based ointments, creams, or lotions. For fungal infections, an antifungal nail polish is used as the first-line treatment and may be supplemented with oral medication if necessary, according to Dr. Zaraa. Thus, white spots on the nails caused by a fungal infection can be treated in a targeted and effective manner as soon as the diagnosis is made.
