Lice are parasitic, which means they must live in a host to reproduce. The adult female louse lays five to six eggs a day, which they deposit in nit shells near the scalp. These eggs hatch into nymphs, which molt several times over the next nine to fifteen days. After nymphs emerge, they die and are no longer a source of reinfestation. Lice cannot survive in temperatures below 74 degrees F.
The Centers for Disease Control estimates that 6 to 12 million people contract head lice every year. Most cases are in children between the ages of three and eleven, who are more likely to come into close contact while playing. The first sign that your child may have head lice is the presence of nits, which are the eggs laid by the lice. These tiny eggs are white or cream colored and oval-shaped.
The best way to prevent lice is to avoid sharing your personal belongings with other people. Always wash your bedding and clothing in hot water. In addition, boil or freeze any hair ties. Don’t use pesticide sprays on your child’s personal items, as these will expose the rest of the household to the harmful chemicals and may damage your child’s hair. If you can’t wash personal items, you can use a plastic bag to store them in for at least two weeks. Another way to kill lice is by washing hairbrushes and combs in hot water, or soaking them in medicated shampoo. If you cannot do this, you can put them in the dishwasher.
Lice cannot live for more than 16 hours without a blood meal. It is best to change clothes and bathe regularly. During the initial stages, lice and their eggs live on clothing and bedding. If they are present on your body, you can kill them with hot water and detergent, but they can remain in your clothing for up to 10 days before they hatch.