Head lice are thought to be spread mainly through direct head to head (hair to hair) contact (9,10). Lice do not hop or fly but can crawl at a rapid rate (23 cm/min under natural conditions) (8). There continues to be controversy about the role fomites play in transmission (8).
Head lice have no wings and do not fly or jump, but they can crawl or run through hair quickly. Most commonly, head lice are spread by direct head-to-head contact with an infested person.
The risk of getting infested by a louse that has fallen onto a carpet or furniture is very small. Head lice survive less than 1–2 days if they fall off a person and cannot feed; nits cannot hatch and usually die within a week if they are not kept at the same temperature as that found close to the scalp.
Head lice cannot live for long on pillows or sheets. It is possible for a live louse that has come off a person's head to crawl onto another human host who also puts their head on the same pillows or sheets.
Exposing lice and nits to temperatures above 125 degrees F for 10 minutes is lethal. Most personal articles of clothing and bedding can be disinfested by machine washing in hot water or machine drying for at least 20 minutes using the hot cycle.
The proportion of lice killed varied from 10% with the bonnet‐style hair dryer to 80% with the Louse‐Buster with hand piece.
Lice are most often spread by head-to-head contact with another person who has lice, such as sleeping in the same bed. Although they do not survive long away from a human host, lice may also be spread by wearing another person's hat or clothing, or by using another person's comb, brush, or bedding.
Head lice are most active at night. Itching is the first and most common symptom but may not appear for weeks after contracting lice.
Coconut, tea tree oil, lavender, eucalyptus, rosemary, lemon grass, and peppermint are scents popularly believed to repel lice. Using any coconut scented shampoo and conditioner is an easy way to increase your defense. At 1% concentration, tea tree oil killed 100% of head lice after 30 minutes.
A tickling sensation in the scalp
Not everyone feels lice moving around on their scalp, but some people do. Dr. Garcia says that most of her patients say they “don't feel anything,” but others may get a creepy, tickling sensation as lice move around their head.
To survive, adult head lice must feed on blood. An adult head louse can live about 30 days on a person's head but will die within one or two days if it falls off a person. Adult female head lice are usually larger than males and can lay about six eggs each day.
Head lice will not go away on their own. If you think your child has an infestation, there are several steps you should take right away. Call your doctor to confirm the diagnosis. Notify your child's day care or school so other students can be checked.
Although sometimes more tedious than chemical methods, mechanical lice treatment methods are far more effective at destroying lice for good. Lice may develop resistances to certain chemicals; however, they will never be able to resist being squished, zapped, smothered, or manually removed by the human hand.
Lice and nits can live on pillows and sheets. Lice glue their eggs to the hair strands of their host. However, if a piece of hair with an egg falls out while the lice host is sleeping, an egg could end up on pillows or sheets.
Can someone have nits but no lice? It may be possible to have nits but no lice. If a person cannot find any nymphs or adult lice in the scalp and the nits are more than a quarter of an inch from the scalp, these may be dead and from an old infestation.
Adult lice can live up to 30 days on a person's head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.
Permethrin lotion 1% is approved by the FDA for the treatment of head lice. Permethrin is safe and effective when used as directed. Permethrin kills live lice but not unhatched eggs.
Washing clothes in hot water (>60°C) for >10 min kills clothes lice and their eggs (30).
As previously discussed, hair color may kill the bugs, but with a full-blown infestation, can lice survive hair dye? Yes, they can. You may be successful at getting rid of some of the bugs with hair dye, or you may even use hair dye to get rid of all of them.
Hairspray makes it harder for the louse to grab hold. The smell of hairspray and the use of solvents (sad but true) in them can also deter creepy crawlies from finding their way in. Not to mention that if you're tying longer hair back, you've got a double whammy.
Washing, soaking, or drying items at a temperature greater than 130°F can kill both head lice and nits. Dry cleaning also kills head lice and nits. Only items that have been in contact with the head of the infested person in the 48 hours before treatment should be considered for cleaning.
Soaking hair care items (such as combs, brushes, and hair clips) in hot water (at least 130°F) for at least 15 minutes to kill any lice or eggs.