Head lice how is it spread

Clothing and items that are not washable can be dry-cleaned OR sealed in a plastic bag and stored for 2 weeks. Vacuum the floor and furniture, particularly where the infested person sat or lay. However, spending much time and money on housecleaning activities is not necessary to avoid reinfestation by lice or nits that may have fallen off the head or crawled onto furniture or clothing.

Do not use fumigant sprays or fogs; they are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin. To receive email updates about this page, enter your email address: Email Address.

What's this? Head lice must feed off another living body in order to survive. Their source of food is human blood, which they get from your scalp. In fact, they cling to hair strands for dear life when you bathe. Human head lice are categorized into clades based on their genetic makeup. A clade is a group of organisms that are not genetically identical to one another, but share a common ancestor.

The clades of human head lice, named A, B, and C, have different geographic distribution and varying genetic characteristics. According to the Journal of Parasitology , Clade B head lice originated in North America, but migrated to farther reaches of the world, including Australia and Europe. Head lice are thought to have separated from body lice, a similar yet distinct species, a little more than , years ago. The discovery of genetic differences between head and body lice supports theories that this time period is when people began wearing clothing.

While head lice remained on the scalp, body lice mutated into a parasite with claws that can grab on to the smoother fibers of clothing rather than needle-thin hair shafts. Head lice are transmitted from one host to another through close personal contact. For the most part, this means that a non-infested person would have to be in head-to-head contact with an infected person. Sharing combs, brushes, towels, hats and other personal items can hasten the spread of head lice.

The louse travels by crawling. Items that cannot be washed can be sealed in a plastic bag for 2 weeks or dry cleaned. Home treatment usually gets rid of head lice. If your child or someone else in your family still has head lice after a few weeks, it means that the treatments have not worked, and an appointment should be made to see a dermatologist.

Several products are available over the counter OTC for treating head lice. OTC medications containing 1 percent permethrin or pyrethrins can be effective , although in some areas, the lice have developed a resistance to these products.

Here is a list of medicines for head lice that are approved by the FDA. Check with a doctor before beginning treatment. If the problem persists or recurs, parents should carry out regular checks and treat the lice as soon as possible with a suitable preparation. Pediculicides kill lice, and some can kill the eggs, or nits, too. If the chosen product is not effective against nits, regular treatment is recommended.

Otherwise, retreatment is recommended only if live lice are found several days after treatment. Female lice can begin laying eggs from 9 days after hatching. To break the cycle and stop the lice spreading, the lice need to be removed within 9 days of hatching.

The most effective strategy is to apply treatment after all the eggs have hatched but before the new lice are mature enough to lay more eggs. FDA-approved treatments for head lice include both OTC and prescription drug s such as Nix and Rid, in the forms of shampoo, creams, and lotions.

It is important to examine labels carefully and read all instructions before use, to make sure the product is safe for the child and their age group. In areas where there is known to be resistance to an OTC treatment, or when attempts to remove an infestation without medical help have not worked, the child should see a doctor. A pediatrician can prescribe medication such as spinosad or topical ivermectin. Prescription drugs approved by the FDA include :.

Permethrin cream 1 percent is available without a prescription. It is applied to hair that has been shampooed and towel-dried, but not conditioned, then rinsed off after 10 minutes. Permethrin will not kill all the eggs at this time, but it will leave a residue on the hair that is designed to kill nymphs emerging from the 20 to 30 percent of live eggs that remain. The application should be repeated 7 to 10 days later, if live lice are seen.

Pyrethrin-based shampoo or hair mousse is available without a prescription. It is applied to dry hair and rinsed off after 10 minutes. Pyrethrins, including permethrin, should be avoided in people who are allergic to chrysanthemums and similar plants, as they contain ingredients that are derived from the chrysanthemum. No residual pediculicidal activity remains after rinsing.

In addition, none of these natural pyrethrins are can completely kill the eggs, and 20 to 30 percent of the eggs will remain viable after treatment. This means a second treatment will be needed to kill newly emerged nymphs hatched from eggs that survived the first treatment. Evidence based on the life cycle of lice suggests that day 9 is the best day for retreatment. However, lice can adapt to this neurological effect, and resistance to 1 percent permethrin has been reported.

In some places in North America, effectiveness has fallen to 20 to 30 percent. Malathion lotion 0. It should be applied to dry hair, left to dry, and rinsed off after 8 to 12 hours. It is effective at eliminating louse eggs. After hatching, the remaining shell looks white or clear and stays attached to the hair shaft. This is when it's easiest to spot them, as the hair is growing longer and the egg shell is moving away from the scalp.

Adult lice and nymphs baby lice. Adult lice are no bigger than a sesame seed and are grayish-white or tan. Nymphs are smaller and become adult lice about 1—2 weeks after they hatch.

This life cycle repeats itself about every 3 weeks. Most lice feed on blood several times a day, and they can survive up to 2 days off the scalp. With lice bites come itching and scratching. This is due to a reaction to the saliva spit of lice. But the itching doesn't always start right away. It depends on how sensitive a child's skin is to the lice. It might take weeks for kids with lice to start scratching. They may complain, though, of things tickling or moving around on their heads.

Small red bumps or sores from scratching. Some kids have mild irritation from scratching, while others may get a bothersome rash. Scratching a lot can lead to a bacterial infection. Watch for swollen lymph nodes glands on the back or front of the neck, and red, tender skin that might have crusting and oozing. Doctors can treat a skin infection with an antibiotic. How Are Head Lice Treated?

The two main ways to treat lice are: medicine removing by hand Medicine: Medicated shampoos, cream rinses, and lotions are available that kill lice. Are Head Lice Contagious? Pets can't catch head lice and pass them on to people or the other way around. Can We Prevent Head Lice? To get rid of head lice and their eggs, and to help prevent them from coming back: Wash all bed linens, stuffed animals, and clothing used during the 2 days before treatment any lice that fell off before that will not be alive.

Dry clean items that can't be washed. Or put them in airtight bags for 2 weeks. Vacuum carpets and any upholstered furniture in your home or car , and throw away the vacuum cleaner bag. Soak hair-care items like combs, barrettes, hair ties or bands, headbands, and brushes in hot water or throw them away.