Why do head lice seem to appear overnight?
Head lice are very active and they will move from head to head very quickly. The moment they infest a new head, each female will lay 6 to 8 eggs every day. These eggs hatch 7 to 10 days after, and the newly hatched lice will themselves begin to lay eggs by the time they are just 7 days old! By the time you notice the first head louse you already have hundreds in your hair.
