Lice are a very often problem mostly for kids. They are contagious and very hard to get rid of. Even though they are annoying they are not that dangerous. They don't spread disease, but they do make kids scratch their heads an scratching can lead to infection.
How can I prevent from getting lice? A reason kids get lice more than adults is because they share more things. For instance things that you can do to prevent you from getting lice are don't share hats, combs, pillows, and towels. You can also give yourself some distance from someone who has lice.
When to call a doctor? You can call a doctor who can do a over-the-counter lice check. I would suggest going if you have symptoms of either itching your head at night or if you have severe side effects after using a lice treating product.