Medically speaking, those little white marks that sometimes appear as dots or lines on finger and toenails are known as leukonychia. They are usually benign and due to an injury, an allergy, or a vitamin deficiency. For the most part, you can treat white spots at home with a variety of natural remedies. If white spots do not clear up, see a doctor for evaluation. In rare cases, white spots on nails can indicate underlying medical issues.