Lice are tiny insects that live on and crawl through the hair. They are gray, brown, or black and can be difficult to see. They do not leave the human host on their own - they must be physically dislodged. They do not infest pets, furniture, carpeting or toys. Head lice live only on the heads of their human hosts.

Resources for the general public

• Lice facts, CDC
• Parásitos - Piojos de la cabeza (en español), CDC

Resources for health care professionals

• Multiple articles from American Academy of Pediatrics
• Treatment guidelines, CDC