The cause of dark-colored toenails is considered to be due to malnutrition, local trauma, fungal infection and other factors.
1. Malnutrition: If the patient often picks food and deviates from food, in the case of insufficient nutrition, it may cause the toenail at the end of the limb to be underdeveloped, thus appearing the symptoms of no luster and dark color.
2. Local trauma: the cause of dark toenails may be due to the heavy object hitting or excessive extrusion factors, which can also cause under-nail bleeding, appearing dark toenails.
3. Fungal infection: When the patient’s toenails have fungal infection, it may cause thickening and darkening of the toenails, and even symptoms such as toenail loss, which is also known as onychomycosis.
There may be other reasons for the darkening of the toenails, so it is recommended to consult a doctor for further examination and treatment.