In reality, these spots most often develop as a result of mild to moderate trauma to your nail. If you can't think of anything that would have injured your nail, consider the fact that nails grow very slowly, so the injury may have occurred weeks before the spots ever appeared. Another possibility is that the spots could be a sign of a mild infection or allergy, or a side effect of certain medications. Whatever the source of the injury, these spots typically do not require any treatment and should go away as your nail grows out. And they should not return unless you suffer another nail trauma. However, this generally applies when only a single or a few nails are affected. If all of your nails are showing white spots or streaks, the leukonychia could be related to another more serious condition such as anemia, cardiac disease, cirrhosis, diabetes or kidney disease.