Infested children usually carry fewer than 20 mature head lice (more commonly less than 10), each of which, if untreated, live for three to four weeks (5–7). Head lice stay close to the scalp for food, warmth, shelter and moisture (6,7).
Typically, 10–15 head lice are found. The number of lice often depends on personal hygiene, for example, how often the person bathes, shampoos, or changes and washes his/her clothing. The number found will also depend on how long the infestation has been ongoing.
Usually children have no more than 10 to 20 live lice. Good lighting is important when you are checking. Head lice move fast and are hard to see. They are usually found very close to the scalp, at the bottom of the neck and behind the ears.
Adult female head lice are usually larger than males and can lay about six eggs each day.
After each treatment, checking the hair and combing with a nit comb to remove nits and lice every 2–3 days may decrease the chance of self–reinfestation. Continue to check for 2–3 weeks to be sure all lice and nits are gone.
Common signs and symptoms of lice include: Intense itching on the scalp, body or in the genital area. A tickling feeling from movement of hair. The presence of lice on your scalp, body, clothing, or pubic or other body hair.
With effective treatment, head lice will completely go away after two to three weeks. The duration is dependent on how many lice made a home in your hair. Make sure you follow the instructions on your medicated shampoo, lotion or cream to get rid of lice quickly.
Once the lice have spread to the person's head, the female louse will start to lay their nits or eggs; an infestation has begun. The first nymphs, or baby lice, will appear 7-10 days later. Nymphs will continue to eat and grow over the next 7-10 days.
Continue to check hair and use the nit comb to remove nits and lice every 2 to 3 days for 2 to 3 weeks. This process should be done for as long as nits and lice are still found on the head. Many lice medicines recommend a second treatment in 9 to 10 days.
An infestation with lice is called pediculosis. In a normal healthy child, an infestation usually involves less than 10 live lice (7). Infestations may be asymptomatic.
Use heat. Wash any items used or worn by the person in hot water, and dry them on high heat. Lice and nits die when exposed to temperatures higher than 130 F for more than 5 minutes. Wash anything that touched the person's skin or scalp, including jackets, hats, scarves, pillowcases, sheets, and headbands.
There are two reasons for a recurrent lice infestation: The lice treatment you used didn't work. You or someone in your family came in contact with lice again.
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. However, the lice could be in hiding.
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. Life cycle image and information courtesy of DPDx.
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.
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.
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.
Heat Method:
There are recent studies that show that treatment of lice with heat can be quite effective in killing head lice. Products such as Lousebuster are very effective but even a home hairdryer can successfully treat lice.
Lice can be hard to get rid of. If you still have lice 2 weeks after you started treatment, let your doctor know. Your doctor may want to try a different medication or repeat treatment in case any nits were left behind and hatched after treatment.
Can head lice live on pillows or sheets? 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.
If you do not comb out all the remaining nits, they will hatch and restart the cycle in 7-10 days from that point. That's why we recommend 3 treatments over a 12-day period of time. This stops the life cycle of lice. These are nits at different stages and a louse.
Anyone can get head lice. They are not a sign of being dirty. Most people don't know they are infested until they see the nits or lice. They are found throughout the world, most commonly on children.