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How to deal with lice

There is probably nothing more feared at the beginning of the school year than the head louse. This tiny, sesame-seed sized insect has been known to put school nurses, administrators, parents and boards of health into a state of panic. Why all the fuss and bother? Do head lice truly represent some kind of health crisis? Do they carry disease? And how can we be rid of them?
How to deal with liceWhat about lice?
Much of the loathing associated with head lice is probably misdirected from its cousin, the body louse. Body lice are very different from head lice and are signs of uncleanliness and unhealthy living conditions. They are known carriers and transmitters of diseases, notably typhus and trench fever. Body lice are still a scourge in America, principally among the homeless and those living in very substandard housing.

The bad news about head lice is that they are much more prevalent than body lice, affecting six to 12 million Americans each year, according to the Centers for Disease Control and Prevention. The good news is that head lice have never been shown to transmit any diseases. Nor are head lice an indication of poverty or substandard living conditions; "cleanliness has absolutely nothing to do with lousiness," according to Richard J. Pollack, PhD, Harvard School of Public Health.

What about other head lice myths?
Head lice can fly.
No. The head louse is a six-legged insect that has no wings. Nor is it considered an especially good jumper. Lice spread mostly from one person to another after they spend time close together, such as in head-to-head conversation or sharing a bed. Girls are afflicted by head lice more often than boys, presumably because they tend to play in closer proximity to each other than boys.

Head lice breed in the furniture or in the carpet. No. Head lice depend on their human host for their food, warmth and shelter. While they can leave one human for a couch and then crawl onto another human's scalp, they cannot live more than 24-48 hours off the human scalp.

Head lice prefer long hair.
They love any scalp hair that is long enough to grab onto and affix their eggs. They always deposit their eggs on the hair shafts within about 1/2-inch of the scalp. In fact long, thick hair may make it more difficult to spread lice because it would be more difficult for the lice to get from the scalp to the surface of a dense head of hair. As mentioned above, girls tend to get lice more frequently because they spend more time in head-to-head play, and not because of the length of their hair.

Head lice carry disease.
Just plain no.

How is it diagnosed?
An itchy scalp is the cardinal symptom of head lice. That itching may then cause us to look more carefully at the scalp where we see white things about 2 inches from the scalp, and we then have our diagnosis, Right? WRONG! If we find white casings (or nits) on the hair shafts, it is evidence of prior -- not necessarily current -- infection.

Be careful though -- dandruff and other scalp debris (such as unrinsed conditioner, etc) -- can appear as whitish dots on the hair. The lice casings are stuck tightly onto the individual hair shafts, and are not easily removed. Also, as mentioned above, the nits to worry about are the ones closest to the scalp; any further than a 1/2 inch from the scalp may be left over from a prior event.

The only way a true diagnosis of head lice infestation can be made is by seeing a living louse. The best way to do that is wash, condition (it makes the hair shafts slipperier) and then towel-dry the hair so it is damp, but not dripping. You will need a lice comb (metal or plastic with very closely spaced teeth -- 0.2-0.3 mm).

Find a well-lit space. Comb the hair first thoroughly with a regular comb to remove tangles, etc. Then with the lice comb, start at the scalp and work to the end of all the hair, working in sections to make sure you get every hair. After each pass, examine the comb or wipe it on a white paper towel. If head lice are present, you should be able to trap one with the comb using this technique.

Interestingly enough, those who do have an infestation probably only have about a dozen insects in their hair at any one time. Remember, lice do not have wings, so if you come up with a winged insect, you probably want to get rid of it, but it isn't a louse. If you don't find a louse, but you do find eggs or nits close to the scalp, you should repeat the process in a day or two. The experts recommend that no one be treated if no live lice are found.

How to treat
Now that we've got a diagnosis, how can we make them go away? Surprisingly enough, the best treatments are the ones that are also the most readily available -- the Over The Counter (OTC) products. These products are known as pyrethroid pediculicides because they are derived from natural insecticidal compounds extracted from the head of the chrysanthemum flower. Piperonyl butoxide, another insecticide may be added in as its presence improves the activity of the pyrethrins.

Brand names include RID, A-200, R & C, Clear, Tegrin-LT and Pronto among others, and they are available as mousse, gels, liquid, and shampoos. NIX contains 1 percent permethrin which is a synthetic pyrethroid formulated into a creme rinse. For very resistant cases, there are also prescription remedies, notably malathion 0.5 percent lotion (Ovide) and the most toxic of the remedies, lindane 1 percent (Kwell and other brands).

But everybody says those OTC products don't work all that well, Right? So why not save time and money and go right to the prescriptions? The fact is, if the OTC preparations are used correctly, they are very effective and safe. If we've got to do this treatment, let's give ourselves the best chance of success by taking time to do it right the first time.


  • Read the label completely and follow the directions carefully.


  • Choose a well-ventilated, well-lit room.


  • You may wish to use towels to protect clothing.


  • Avoid contact with the eyes, and avoid rubbing your eyes before you've rinsed your hands thoroughly.


  • Most of the products are applied to dry hair; Permethrin (NIX) is applied to damp but not wet hair (towel-dry the hair thoroughly; if the hair is too wet, the product will become too dilute).


  • Apply a few drops of the medicine directly onto the scalp and work it in. Do this section by section, and be sure the scalp and roots are saturated. Remember that the active eggs and nits are the ones closest to the scalp. If the hair is very long, concentrate on the 5 to 6 inches of hair nearest the scalp.


  • Don't try to save money by scrimping on the amount you use; if the hair is very thick and curly, you may need to use more than one bottle. You really don't want to have to do this more times than necessary.


  • Once the scalp and roots are taken care of, work the product down to the ends of the hair.


  • Do not start timing the treatment until the entire head has been treated. Leave it on for as long as the directions say.


  • Remove as per the directions. For pediculicide shampoos, add just enough water to make lather, and then rinse. If a gel or mousse and you need to shampoo it out, do not use a conditioning shampoo, as this might cause the medicine not to adhere to the hair shaft.


  • Malathion (Ovide), a prescription treatment, must be allowed to dry on the hair, but it is flammable, so do not use a hair dryer.


  • Check the scalp eight to 12 hours after treatment, and comb out the dead lice and debris. Some have found it easier to comb the nits out if vegetable oil or vinegar have been applied to the hair after removal of the treatment. Commercial preparations to loosen nits are also available.

    Some formulations will require a second applications seven to 10 days later to get some lice that may have been protected by their egg cases. Reapply only as directed on the package label.


  • Using pesticides for longer than recommended or more frequently than recommended will not make them work more effectively, but may cause them to irritate the skin more.

    Remember all of the above medicines are for external use only, and are not to be put in the mouth! Keep these and all medicines out of the reach of children.

    What about "home remedies?"
    An Egyptian medical manuscript, believed to date back to 1500 BC, prescribed date flour and water as a cure for lice. In the 3,500 years since then, there have probably been a like number of remedies. Some seem to help, some are yet to be proven, and some are dangerous. A British study found that combing (as described under "How to Diagnose" above) every three or four days for two weeks cured approximately 38 percent of children. Shaving the head is a simple, but drastic, cure but not advised if the child is unwilling; cutting the hair shorter will make diagnosing and treating easier but will not get rid of an active case.

    In the "As-yet-unproven" category we find the applecation of dense substances such as mineral oil, petroleum jelly, margarine or mayonnaise in an effort to smother the lice. In addition to then taking days to rinse out of the hair, these substances would not kill the eggs and would need to be repeated in seven to 10 days. Also unproven is the use of oral antibiotics to kill some of the body's intrinsic bacteria that produce nutrients that might help the lice.

    From the "Potentially dangerous" file are many of the Internet-available remedies containing ingredients advertised, but medically unproven, to be natural insecticides. Some products have been shown to be irritating to the scalp and, as with all medicines, many are dangerous if ingested. Unfortunately, just because an ingredient is "natural" or found in nature doesn't make it safe; arsenic and hemlock are "all natural." Check with your healthcare provider for his or her recommendations for alternative remedies.

    And from the "Definitely dangerous and foolish" category comes the application of any dangerous substances such as kerosene, gasoline, bleach, acetone, turpentine or motor oil.

    Scouring the house
    If there's any good news in all of this, it's that you don't have to strip the walls down to plaster to clean up after the treatment. Remember, the louse can live for only one to two days separated from a human host. A prudent clean-up effort might include:


  • Bed linens, towels, pajamas and the clothes worn for the two days before treatment should be washed in hot water and dried on high heat. It would be best to do this bit of cleaning on the morning after the treatment was given, in order to clean up the dead insects that might have fallen off during the night.


  • Dry clean items from the above list that can't be washed.


  • Soak brushes and combs in dish detergent and hot water for an hour, and then rinse. Temperatures greater than 129F (53.5C) for five minutes are lethal to lice and eggs. They could also be soaked in rubbing alcohol.


  • Vacuum the floors, furniture and any car seats.


  • For younger children with special stuffed animals, these also need to be washed. Alternatively, if they cannot be washed, they can be sealed in a plastic bag for 10 days.

    What about others in the house?
    Once there is one case of head lice in the home, all the other residents should be carefully checked. If lice are found on more than one family member, all the affected people should be treated at the same time to avoid the chance of reinfection (and to make for only one house-cleaning!).

    What is a "No Nit Policy" and is it worthwhile?
    A "No Nit Policy" states that a child may not return to school until the hair is free of lice and their egg casings (nits). At one time it was considered a good safety precaution to keep lice from spreading in the schools. But, as we have discussed above, a nit is a sign that there were head lice in the past, not that there are any now. Still, many school systems and school nurses continue to insist on a "clean as a whistle" scalp before the child can return to school.

    A study by the CDC found that only 18 percent of children with nits in their hair developed lice within the next two weeks. Neither the American Academy of Pediatrics (AAP) nor the National Association of School Nurses (NASN) believes in the "no nit" policy. The AAP reports that "Children identified as having...head lice should be excluded from school only until treatment has been started. School contacts generally should not be treated prophylactically." And the NASN concludes that, "Nit-free policies disrupt the education process and should not be viewed as an essential strategy in the management of head lice."

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