White toenails may be caused by localized trauma, infectious factors, malnutrition and other factors. 1. Local trauma: toenail suffered injury, resulting in local damage, may cause damage to the structure of the nail plate, will make the toenail white as well as opaque. 2. Infectious factors: poor hygiene or close contact with fungal infections can lead to fungal infections in the toenail area, resulting in gray toenails, and when the lesions worsen, the toenails will become white and brittle, and may be accompanied by thickening, buckling and other symptoms. 3. Malnutrition: prolonged partiality and picky eating, resulting in the lack of vitamins and trace elements in the body, will also make the toenails white, and may be accompanied by fatigue, emaciation and other symptoms. In addition to the above factors, white toenails may also be associated with severe anemia, capillary supply disorders and other factors, it is recommended to seek medical attention for appropriate examination and treatment to avoid adverse effects.