A Washington Toxics Coalition Fact Sheet
Getting Ahead of Lice
by Shamra Harrison
ach year in the United States, as many as 6 million children will be treated for
pediculosis, or head lice. Many parents, sometimes on the advice of theirchild’s school or even their pediatrician, turn to pesticidal products as a
solution. Before using a pesticidal shampoo as a first-line treatment, parents should beaware that alternatives do exist. Parents should also know that careful combing isnecessary to effectively treat head lice, regardless of whether a pesticidal product isused. Careful combing can be effective alone, eliminating the need to use a pesticidalshampoo.
The U.S. Environmental Protection Agency (EPA) recognizes the potential health
risk of pesticidal shampoos and does not recommend their use, except as a last resortin extreme cases. Nearly all pediculosis experts will tell you that careful combing is theonly way to effectively treat a lice infestation. Even the pesticide industry recognizesthat combing is the best defense against head lice. A spokesperson for Warner-Lambert, manufacturer of one of the leading pesticidal shampoos, was quoted assaying, “Frankly, you don’t need any product if you can get the nits without it.”
An adult louse shown actual size in
Should You Use a Pesticide?
circle at left, and enlarged at right.
Parents who decide to use a pesticidal shampoo should educate themselves about
the potential health effects of available products. According to the EPA, the activeingredients lindane and permethrin (see “The Chemicals” on page 43 for brand namesof products containing these pesticides) have been shown to cause cancer in laboratoryanimals. Pesticidal shampoos have caused minor to severe eye and skin irritation.
Cases of seizures and even death associated with the misuse of lindane have beenreported. Lindane and permethrin have both been shown to have neurological effectsand are suspected of disrupting hormone systems. The state of California has bannedthe use of lindane for lice and scabies.
Lindane is particularly dangerous because it is readily absorbed through the skin,
and like other organochlorine insecticides is highly persistent in human fat tissue.
Absorption can be especially great during a shampoo treatment because of the manyblood vessels on the scalp that are close to the skin. When the skin is warm and bloodvessels are dilated, as is often the case when shampooing one’s hair, absorptionincreases further.
Parents should also be aware that Ovine, which contains the neurotoxin malathion,
has been reintroduced as a head lice treatment. According to an article in the February
2000 edition of Consumer Reports
, the amount of malathion contained in one treatment
can be up to 30 times the recognized safe one-time dose for a small child. Ovine’s safety
for children less than six years old has not yet been established.
In addition to containing ingredients that pose health risks, these pesticidal
shampoos may not work as effectively as they claim. The National PediculosisAssociation, a nonprofit organization dedicated to providing information on properhead lice control, has catalogued thousands of anecdotal reports of treatment failures.
Studies have shown that resistance is developing to most of the chemical treatments.
Washington Toxics Coalition, 4649 Sunnyside N, Suite 540, Seattle, WA 98103 (206) 632-1545
Although we do not enjoy dealing with these creepy crawlies, cases of pediculosis
are on the rise. Due to over-use and preventative treatments with these products, manyshampoos are beginning to lose their effectiveness. Before applying one of thesepotentially dangerous pesticidal shampoos to your child’s growing body, rememberthat mechanical removal of lice and their eggs continues to be the best treatmentavailable. Also remember that combing is necessary to remove all lice and their eggs,even if a pesticidal shampoo is used.
Identification and Transmission
Head lice are brown or grayish colored insects, slightly smaller than a flea
(about 1/16 to 1/8 inch long) and oval in shape. An adult female can lay 6-8 eggsper day, which translates to as many as 100 in one female life cycle. An egg takes 7-11 days to hatch and another 8-9 days to reach sexual maturity. An adult can live forup to 30 days.
Their eggs, called nits, are attached to the hair shaft close to the scalp and can be
distinguished from hair debris because they are much harder to remove. Lice are mostcommonly found near the crown of the head, the nape of the neck, and behind the ears.
An active infestation of lice means that live adults or viable nits are present. Viable nitsare yellowish with a pearly luster, whereas hatched nits are greyish and moretransparent. Magnification may be required to properly identify viable nits.
Lice are transferred through head-to-head contact via hats, headphones, brushes,
helmets, barrettes, or headrests. Pets do not transmit head lice. Lice cannot jump or flyand can live away from the human body for only 24 hours. They do not carry diseasesbut can cause head irritation and secondary infections, such as impetigo, due toscratching. Children between the ages of three and ten are most susceptible but peopleof all ages can be infected.
Combing: Your Best Defense
Unfortunately, there is no instant fix when it comes to head lice. No pesticidal
shampoo will kill all nits. The safest, most effective treatment is careful combing toremove lice and their eggs. A fine-toothed, metal comb such as the LiceMeister or LiceOut works best. Either of these products can be purchased from your local drugstoreand the LiceMeister can be ordered from the National Pediculosis Association foraround $15. Combing should be repeated every night for at least 12 days, as nits willcontinue to hatch for 8-11 days. Examine all children and adults in the household andtreat all infected individuals.
Manual removal of lice and their eggs can be a long and tedious process but serves
as your best protection against reinfestation. Seat your child so their head is directlybelow eye level and place a clean towel over his or her shoulders. Fasten back your ownhair to prevent contact with your child’s hair. Have a good book or video ready todistract your child. A half-and-half mixture of vinegar and warm water can be appliedto your child’s hair and left on for 15 minutes to loosen nits. Another useful preparationis salad oil combed into the hair to make brushing easier. Bright natural light or a lampwill make nits easier to spot.
Separate the hair into 1/2 to 3/4-inch sections. Comb through each section starting
at the scalp, dunking the comb in soapy, 130° F water each time you comb out nits orlive lice. A tissue can be used to frequently clean debris from the comb and should be
The safest, most effective lice treatment
discarded into another container of soapy water. Flush the contents of both bowls down
is careful combing to remove lice and
the toilet when full. When combing is finished, shampoo twice to remove oil from the
Once the hair is dry, check the entire head for stray nits, which can be cut out with
a pair of small scissors. Soak the comb and scissors in hot, soapy water for 15 minutesand flush the contents of the bowl down the toilet. Wash all towels used in hot waterand place in the dryer for at least 30 minutes on the high heat setting.
Proper Lice Combing Procedure
❖ Find bright natural light or a strong lamp with a flexible arm that allows
❖ Find something entertaining for your child, such as reading a book,
❖ Apply any kind of salad oil to your child's hair
❖ Sit with your child's head just below your eye level
❖ Brush hair with a large-toothed regular comb and separate into 1/2 to 3/
❖ Starting at the scalp, slowly comb through each section of hair several
Starting at the scalp, slowly comb
through each section of hair several
❖ Each time you comb out lice or nits, dunk the comb into a bowl of
soapy water (frequently remove hair and other debris from the combwith a tissue, discarding into another bowl of soapy water)
❖ Shampoo twice to remove the oil❖ Let hair dry, and recheck for stray nits❖ Cut out any nits with small scissors
❖ Flush the contents of both bowls of soapy water down the toilet
❖ Soak the comb and scissors for 15 minutes in hot soapy water, or boil
❖ Wash towels in hot water and dry on high heat
Combing steps taken from the EPA's "IPM for schools:
A how-to manual." Document #909-B-97-001. March 1997.
May cause cancer in humans,according to the EPA
Natural and Alternative Remedies
In addition to combing, or as a supplement to combing, some parents turn to
natural or home remedies. Mayonnaise, margarine, olive oil, and tea-tree oil are all said
to smother lice when left on the hair for several hours. Several natural products are
currently available, including Hair Clear 1-2-3, Not Nice to Lice, and Lice Out, which
claim to either kill lice or loosen nit glue. None of these treatments has been proven
effective at killing lice but all will, at the least, make it easier to comb nits out of your
Plant-based soaps can also be helpful as an addition to a diligent combing strategy.
Coconut- and olive oil-based shampoos contain fatty acids that are harmful to lice.
These shampoos dry the hair, so make sure to follow with a conditioner.
Some physicians are beginning to prescribe antibiotics such as Septra and Bactrim
(both containing a combination of trimethotrim and sulfamethoxazole) as a treatment
for head lice. They are intended to eliminate a bacterium within the guts of lice which
is necessary for their survival. Harvard School of Public Health does not endorse this
practice for two reasons. First, use of antibiotics has not been proven effective as a
means of treatment for head lice infestations. Second, unnecessary use of these drugs
may accelerate bacteria resistance and diminish the effectiveness of antibiotics that
may be needed to fight life-threatening infections.
Pesticidal Shampoo Safety
If you decide to use a traditional pesticidal shampoo, follow the label instructions
carefully. Never apply a pesticidal product to a child who has open cuts or head
inflammation. Do not apply to eyelashes or brows and cover your child’s face with a
washcloth during treatment to further protect the eye area. Do not treat children less
than two years old, pregnant or nursing women, or anyone with allergies, asthma, or
epilepsy. Always wear gloves when applying. Do not use in a shower or bath, which
increases exposure to the pesticide. Instead, shampoo over a sink or basin. Rememberthat pediculicide shampoos are pesticides and should be stored out of reach of children.
Applying a pesticidal shampoo too often or leaving it on too long unnecessarily
raises your child’s exposure to dangerous pesticides. Use these shampoos only when
you find lice and their viable eggs, never as a preventative measure. Because of reports
of resistance to permethrin, the National Pediculosis Association (NPA) advises that
parents discontinue use of a shampoo at the earliest sign of treatment failure. (Report
any product failures or adverse reactions to the NPA registry at 800-446-4NPA.) Also,remember that a second application of a permethrin or pyrethrin shampoo is necessary
7-10 days later. Incorrect use of pesticidal shampoos can expose lice to low levels of
chemicals that can help them build up a resistance.
If using a pesticidal product sounds like the easiest approach, you should know that
using a pesticidal shampoo does not mean you can avoid manual removal of lice. No
lice shampoo will remove nits. Combing out lice and nits should be the core of any
treatment you decide on. And diligent, careful combing alone can be effective,eliminating any need for a pesticidal product.
Harvard School of Public HealthHead Lice Information, statement
Removing Lice From Your Home
After treating the individual, take some steps to remove lice and eggs from your
home. Wash clothing and bedding in hot water and tumble-dry on high heat for 30minutes. Soak brushes and combs in water above 130° F for 15 minutes. Vacuum floorsand furniture your child may have had contact with. After vacuuming, remove the bag,seal the openings and dispose of it properly. Items that cannot be laundered or vacuumed
can be sealed in plastic bags for 11 days, enough time for nits to hatch and die.
Never use commercial sprays or home fumigants. According to the Centers for
Disease Control and Prevention, NPA, EPA, and Harvard School of Medicine, they are
unnecessary and not worth the health risk. The Director of the National Pest Control
Association states, “There is no scientific justification to spray for head lice at home
or in the school environment. It is our job as pest control professionals to distinguish
ignore it. Frank discussions between par-
between the risks and benefits of certain insects versus certain pesticide applications.
ents, children, child care providers, teach-
Head lice do not qualify for pesticide extermination measures.”
ers, and health care providers are the besttools we have to fight off future out-
Once your child and home are free of lice, there are several things you can do to
their eggs are critical in treating current
prevent further outbreaks. Continue to check for adults and eggs once a week,
infestations, regardless of whether a pes-
especially when cases of pediculosis are being reported in your school or day care.
Educate your children on ways they can protect themselves. Instruct them not to share
weekly for lice will allow you to confront
combs, barrettes, hats, or other headgear. Talk with your child’s teacher or day-care
the problem while it is still manageable.
provider and suggest that coats and hats be stored separately from each other, either in
So remember to add all of that to your to-
lockers, cubbyholes, or on assigned hangers. Ask your school or day-care not to use
indoor sprays to prevent lice outbreaks. Share information with your pediatrician andschool nurse. An excellent source is the National Pediculosis Association at 800-446-
sumes no responsibility for any injury or
Check with your child's school to see if they have an official policy addressing lice.
damage resulting from the use or effect of
A strong school policy should include clearly identified procedures for conducting
any product or information specified in this
routine screenings, training volunteers, notifying parents, managing outbreaks, pre-
publication. Mention of particular products
venting lice transmission, and educating the community. The EPA also recommends
by name does not constitute an officialendorsement.
that one member of the school staff receive training from the school nurse or otherpublic health official in the detection of lice and nits. Like all pest management policiesinstituted in schools, parents and other concerned community members should be
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