how long can lice live off head
Head lice and their eggs (nits) soon perish if separated from their human host. Adult head lice can live only a day or so off the human head without blood for feeding. Nymphs (young head lice) can live only for several hours without feeding on a human.
Eggs hatch after 5 to 10 days. Young head lice (called nymphs) are mobile and molt three times, developing into mature adults in about three weeks. Adults can live for about four weeks but do not lay eggs until after seven days. Head lice do not survive off a host for more than one or two days. Head lice do not jump or fly. They can however move from an infested person to another person during play or other close contact. Head lice may also spread when an infested child shares combs, brushes, scarves, clothing, hats, towels or similar items.