What is the most common cause of leukonychia, or white spots on nails?

Leukonychia, which refers to the appearance of white spots on the nails, is most commonly caused by injury to the nail matrix. When the matrix, which is the tissue underneath the base of the nail, is damaged—whether through trauma, impact, or other forms of physical stress—these white spots can develop as the nail grows out. Since nails grow at a slow pace, it can take time for these spots to become visible, and they will eventually grow out with the nail, reflecting the point of injury.

Fungal infections are less commonly associated with leukonychia; they usually present with other symptoms such as discoloration, thickening, or splitting of the nails. Similarly, while poor nutrition can affect overall nail health and appearance, it is not a frequent cause of the specific condition of white spots. Allergic reactions can lead to changes in nail appearance but typically do not manifest as isolated white spots like those seen in leukonychia.

Understanding that the primary cause of leukonychia is related to physical trauma helps in recognizing the nature of nail health and the importance of protecting the nails from injury to maintain their appearance.