White spots on nails are a common cosmetic issue for many people, though the underlying reasons are often more specific than general wear and tear. The medical term for this phenomenon is leukonychia. “Leukonychia is a condition where people get these white dots or lines on their fingernails,” said Karan Lal, a double board-certified dermatologist. “The most common cause of this is trauma, but it can also be associated with various medical conditions.”
Types of White Spots
Not all white marks are the same. Apparent leukonychia occurs when spots appear on the nail bed underneath the nail and vanish when pressure is applied, explained Brendan Camp, a double board-certified dermatologist. True leukonychia originates from the nail matrix, the area where the nail grows, and appears directly on the nail plate; these spots do not disappear with pressure. There is also pseudoleukonychia, where white spots look like flaking on top of the nail surface and are most frequently caused by fungi.
Common Causes and Health Links
Physical injury is the primary reason for these spots. Trauma from hitting a nail against a hard surface, getting it caught on something, or biting the nails can lead to white discoloration. Dr. Camp also noted that manicures and pedicures may cause white spots due to the tools, polishes, and chemicals used during the service.
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It’s easy to obsess over every minor flaw on a fingernail, but the context often matters more than the spot itself. A solitary mark usually fades, while patterns that repeat across every nail often suggest something deeper is happening within the body. This distinction helps dermatologists determine if the issue is simply a matter of waiting for the nail to grow out or if it requires medical intervention.
Fungal infections are another frequent culprit. “Some fungal infections can cause a white discoloration of the nail plate as opposed to the more traditional yellow color associated with fungal infections,” explained Dr. Camp. Dr. Lal often sees a specific type called superficial white onychomycosis, which is characterized by white flaking on top of the fingernail. Psoriasis is also linked to this condition and can cause onycholysis, which is when the nail plate separates from the nail bed and creates white spots.
Certain medications, including chemotherapy drugs and long-term antibiotics like sulfonamides, have the potential to cause white spots. More serious underlying medical conditions can also be responsible, such as liver disease, kidney disease, and heart failure. “Half and half nails,” where half of the nail is horizontally white, may be an indicator of kidney disease. Muehrcke lines are white lines that run across the nail and may signal a deficiency in albumin protein.
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Diagnosis and Treatment
Diagnostic methods vary depending on the suspected cause. A doctor may scrape the nail to rule out a superficial fungal infection, a procedure Dr. Lal described as “quick, effective, and easy.” A nail biopsy is very rare but involves gathering skin cells for laboratory testing. The main method for finding underlying causes is a full physical exam, which may include a full blood panel to check for internal issues.
Treatment depends entirely on the root cause. “Trauma-related leukonychia will usually grow out with the nail plate over time,” said Dr. Camp. Patients are advised to keep nails trimmed short and avoid tapping, picking, or biting them. If a fungal infection is present, doctors may prescribe antifungal medications. For conditions like psoriasis, systemic therapy is often necessary because psoriatic nails are difficult to treat with topicals.
“White spots can be an indication of underlying medical disorders or infection,” said Dr. Camp. If the spots do not grow out or respond to over-the-counter treatment, a board-certified dermatologist should be consulted. Uniform spots on all nails or accompanying symptoms like swelling also warrant a professional evaluation.
