Leukonychia, or white discoloration of the toenail, is a common phenomenon. This change in color is not always a sign of a serious issue, but it does indicate a change in the composition or structure of the nail plate or the underlying nail bed. Leukonychia can manifest as small white spots or complete whitening of the entire nail. Understanding the different origins of this discoloration is helpful for determining whether medical attention is necessary.
Local Causes Fungus and Trauma
The majority of white toenail cases are the result of external factors acting directly on the nail unit, most commonly fungal infections or physical injury. One of the most prevalent causes is onychomycosis, a fungal infection where organisms like dermatophytes invade the nail structure. Fungi thrive in the warm, moist environment of footwear, making toenails especially susceptible to this type of infection.
Fungal Infections
White superficial onychomycosis appears as distinct, opaque white patches on the nail’s surface. This occurs as the fungus consumes the keratin, the main protein component of the nail plate, causing the nail to become soft and crumbly. Another common presentation is distal subungual onychomycosis, which usually begins as a white or yellowish spot under the tip of the nail and spreads deeper.
The nail plate can also exhibit white, chalky patches called keratin granulations. These patches are dehydrated surface layers often caused by the prolonged use of nail polish or acetone-based removers.
Physical trauma is another frequent cause of white spots or lines, referred to as partial leukonychia. This happens when the nail matrix, where the nail is formed, is injured by events like dropping an object, wearing ill-fitting shoes, or repetitive stress from activities such as running. The injury creates tiny air pockets between the layers of keratin cells in the nail plate, which appear white when light reflects off them. Unlike discoloration from infection, these white spots are temporary and will gradually grow out with the nail plate.
When White Nails Indicate Internal Health Issues
While most white toenails result from localized issues, certain patterns of discoloration can signal underlying systemic conditions. These changes are considered “apparent leukonychia,” meaning the whiteness is due to changes in the nail bed underneath the nail plate, rather than the nail plate itself.
Terry’s Nails
Terry’s nails are a distinct presentation where nearly the entire nail appears white with a “ground glass” opacity, except for a thin, reddish-brown band at the tip. This pattern is thought to be caused by a decrease in blood vessels and an increase in connective tissue in the nail bed. Terry’s nails are strongly associated with chronic conditions, particularly liver disease like cirrhosis, congestive heart failure, or diabetes.
Lindsay’s Nails
Lindsay’s nails, sometimes called “half-and-half” nails, are characterized by the proximal half of the nail being white and the distal half being brown, red, or pink. This dual coloration is most often seen in individuals with advanced chronic kidney disease. The paleness in the proximal section may be due to chronic anemia associated with kidney failure. General paleness in the nails can also be related to conditions like hypoalbuminemia, a protein deficiency seen in malnutrition or certain intestinal disorders.
Diagnosis and Treatment Options
Determining the cause of a white toenail begins with a thorough physical examination and patient history. A healthcare provider inspects the pattern of discoloration, its location, and whether it affects multiple nails to differentiate between local trauma, fungal infection, and systemic disease. If a fungal infection is suspected, the provider may take a small scraping or clipping of the affected nail. This specimen is sent to a laboratory for analysis, which may include a potassium hydroxide (KOH) test or a culture to identify the specific type of fungus present.
Treatment is determined entirely by the underlying diagnosis. For white spots caused by trauma, no medical intervention is necessary, and the nail simply needs time to grow out, which can take up to a year. If a fungal infection is confirmed, treatment options include topical antifungal medications for superficial infections, or oral antifungal drugs for more severe cases. If the white discoloration signals an internal health issue, such as Terry’s or Lindsay’s nails, treatment focuses on managing the underlying systemic medical condition. It is advisable to consult a professional if the whiteness spreads, is accompanied by pain, or if similar changes appear across multiple nails.