Lice are Not Nice
Lice Are Not Nice
(But Anyone Can Get Them)
Head lice are tiny insects that live only on people's scalps and hair. They are 1-3mm long and their color can change based on the color of the hair of the person they are infesting. They avoid light, which makes it difficult to see them. Nits are tiny, plump, pearl gray colored, oval-shaped eggs attached to the hair near the scalp. The nits are firmly attached to the hair and cannot be easily moved up or down the hair (as could specks of dandruff). Diagnosis is more often made by finding nits within 1/4-inch of the scalp, although treatment should be held until finding an actual louse.
The adult lice hatch from small eggs, called nits, which are attached to the individual hairs near the scalp. Nits may be found throughout the hair, but are most often located at the back of the scalp, behind the ears and the top of the head. The eggs hatch in 7-10 days, with new lice reaching adulthood in about 10 days. The female louse can live for 21-30 days, and lays about six to ten eggs a day. Head lice cannot hop or fly, they crawl. The lice live by biting and sucking blood from the scalp.
Persistent scratching of the head and back of the neck should be viewed with suspicion. Often red bite marks and scratch marks can be seen on the scalp and neck. All household members and persons with close physical contact with the infested person should be examined for lice and treated if live lice are seen.
There are several medicines available to kill head lice:
Pyrethrins, like RID, are available in shampoo or mousse formulations that are applied to dry hair and left in for 10 minutes before they are rinsed out. No residual medicine is left behind and none will totally kill all the eggs. That means 20-30% of the eggs will still be okay and require a second treatment which is most recommended for day 9.
Permethrins, like Nix, arecome as a cream rinse that are applied to wet hair and scalp and left in for 10 minutes before rinsing out. They leave a residue on the hair that is designed to kill nymphs emerging from 20-30% of the eggs not killed with the first application. At this point they still recommend a second treatment in 7-10 days, although some places are saying that is not necessary.
Although these products will kill lice, none will kill 100% of the nits. Nit removal after shampooing may be time-consuming and difficult due to their firm attachment to the hair. A solution of vinegar and water may help make removal easier. Special, finetoothed combs can be used to aid in nit removal. A daily nit check for the next 10 days is advisable.
Head lice usually survive for less than 1 day away from the scalp at room temperature and their eggs cannot hatch at ambient temperatures lower than near the scalp. In one study the American Academy of Pediatrics quoted, after studying a group of highly infested individuals, only 4% of their pillow cases were found to have live lice on them. For this reason many of the previous recommendations about cleaning your house have been decreased to just washing your pillowcase. However, the NH Department of Health and Human Services still recommends that you machine wash in HOT water all washable items that may contain lice. Machine wash in HOT water all washable items belonging to the day care facility that may contain lice. Things that cannot be washed, dried or dry cleaned can be sealed in a plastic bag for two weeks. Soak combs and brushes for 1 hour in rubbing alcohol, Lysol, or wash with soap and hot (130°F) water. Vacuum the floor and furniture. The risk of getting reinfested from a louse that has fallen onto a carpet or sofa is very small.
Routine exclusion of school-aged children with head lice is not recommended. A child should be allowed to return to school after proper treatment even if nits are still present.