Health & Nutrition
Head Lice Infestation (Pediculosis)
What are head lice?
Also called Pediculus humanus capitis (peh-DICK-you-lus
HUE-man-us CAP-ih-TUS), head lice are parasitic insects found on the heads of
people. Having head lice is very common; as many as 6-12 million people
worldwide get head lice each year.
Who is at risk for getting head lice?
Anyone who comes in close contact with someone who already has
head lice, contaminated clothing, and other belongings. Preschool and
elementary-age children, 3-10, and their families are infested most often. Girls
get head lice more often than boys, women more than men. In the United States,
African-Americans rarely get head lice.
What do head lice look like?
There are three forms of lice: the nit, the nymph, and the
adult.
Nit: Nits are head lice eggs. They are hard to see and
are often confused for dandruff or hair spray droplets. Nits are found firmly
attached to the hair shaft. They are oval and usually yellow to white. Nits
take about 1 week to hatch.
Nymph: The nit hatches into a baby louse called a
nymph. It looks like an adult head louse, but is smaller. Nymphs mature into
adults about 7 days after hatching. To live, the nymph must feed on blood.
Adult: The adult louse is about the size of a sesame
seed, has six legs, and is tan to greyish-white. In persons with dark hair,
the adult louse will look darker. Females lay nits; they are usually larger
than males. Adult lice can live up to 30 days on a person's head. To live,
adult lice need to feed on blood. If the louse falls off a person, it dies
within 2 days.
Where are head lice most commonly found?
On the scalp behind the ears and near the neckline at the back
of the neck. Head lice hold on to hair with hook-like claws found at the end of
each of their six legs. Head lice are rarely found on the body, eyelashes, or
eyebrows.
What are the signs and symptoms of head lice infestation?
- Tickling feeling of something moving in the hair.
- Itching, caused by the an allergic reaction to the bites.
- Irritability.
- Sores on the head caused by scratching. These sores can sometimes become
infected.
How did my child get head lice?
By contact with an already infested person. Contact is common
during play at school and at home (slumber parties, sports activities, at camp,
on a playground). By wearing infested clothing, such as hats, scarves, coats,
sports uniforms, or hair ribbons. By using infested combs, brushes, or towels.
By lying on a bed, couch, pillow, carpet, or stuffed animal that has recently
been in contact with an infested person.
How is head lice infestation diagnosed?
By looking closely through the hair and scalp for nits, nymphs,
or adults. Finding a nymph or adult may be difficult; there are usually few of
them and they can move quickly from searching fingers. If crawling lice are not
seen, finding nits within a 1/4 inch of the scalp confirms that a person is
infested and should be treated. If you only find nits more than 1/4 inch from
the scalp, the infestation is probably an old one and does not need to be
treated. If you are not sure if a person has head lice, the diagnosis should be
made by a health care provider, school nurse, or other healthcare professional.
How can I treat a head lice infestation?
By treating the infested person, any other infested family
members, and by cleaning clothing and bedding.
Step 1: Treat the infested person/any infested family members
Requires using an OTC or prescription medication. Follow these
treatment steps:
- Before applying treatment, remove all clothing from the
waist up.
- Apply lice medicine, also called pediculicide (peh-DICK-you-luh-side),
according to label instructions. If your child has extra long hair, you may
need to use a second bottle. WARNING: Do not use a creme rinse or combination
shampoo/conditioner before using lice medicine. Do not re-wash hair for 1-2
days after treatment.
- Have the infested person put on clean clothing after
treatment.
- If some live lice are still found 8-12 hours after
treatment, but are moving more slowly than before, do not retreat. Comb dead
and remaining live lice out of the hair. The medicine sometimes takes longer
to kill the lice.
- If no dead lice are found 8-12 hours after treatment and
lice seem as active as before, the medicine may not be working. See your
health care provider for a different medication and follow their treatment
instructions.
- A nit comb should be used to remove nits and lice from the
hair shaft. Many flea combs made for cats and dogs are also effective.
Finer-toothed nit combs, available through Wal-Med* and the National
Pediculosis Association*, may also be helpful.
- After treatment, check hair every 2-3 days and use a nit
comb to remove any nits or lice you see.
- Retreat in 7-10 days.
- Check all treated persons for 2-3 weeks after you think
that all lice and nits are gone.
Step 2: Treat the household
- To kill lice and nits, machine wash all washable clothing
and bed linens that the infested person touched during the 2 days before
treatment. Use the hot water cycle (130o F) to wash clothes. Dry laundry using
the hot cycle for at least 20 minutes
- Dry clean clothing that is not washable, (coats, hats,
scarves, etc.) OR
- Store all clothing, stuffed animals, comforters, etc., that
cannot be washed or dry cleaned into a plastic bag and seal for 2 weeks.
- Soak combs and brushes for 1 hour in rubbing alcohol,
Lysol*, or wash with soap and hot (130o F) water.
- Vacuum the floor and furniture. Do not use fumigant sprays;
they can be toxic if inhaled.
My child has head lice. I don't. Should I treat myself to
prevent being infested?
No, although anyone living with an infested person can get head
lice. Have another person check the back and sides of your head for lice and
nits. Check family members for lice and nits every 2-3 days. Treat only if
crawling lice or nits are found within a 1/4 inch of the scalp.
Is there a product I can use to prevent getting head lice?
No.
Should my pets be treated for head lice?
No. Head lice do not live on pets.
My child is under 2 years old and has been diagnosed with
head lice. Can I treat him or her with prescription or OTC drugs?
No. For children under 2 years old, remove crawling bugs and
nits by hand. If the problem persists, consult your pediatrician.
What OTC medications are available to treat head lice?
Many head lice medications are available at your local drug
store. Each OTC product contains one of the following active ingredients.
- Pyrethrins (pie-WREATH-rins): often combined with piperonyl
butoxide (pie-PER-a-nil beu-TOX-side): Brand name products: A-200*, Pronto*,
R&C*, Rid*, Triple X* Pyrethrins are natural extracts from the
chrysanthemum flower. Though safe and effective, pyrethrins only kill crawling
lice, not unhatched nits. A second treatment is recommended in 7- 10 days to
kill any newly hatched lice. Sometimes the treatment does not work.
- Permethrin (per-meth-rin): Brand name product: Nix*
Permethrins are similar to natural pyrethrins. Permethrins are safe and
effective and may continue to kill newly hatched eggs for several days after
treatment. A second treatment may be necessary in 7-10 days to kill any newly
hatched lice. Sometimes the treatment does not work.
Note: If OTC permethrin (1%) does not effectively kill
crawling bugs, prescription- strength (5%) permethrin will not be any more
effective. If lice are resistant to 1%, they will also be resistant to 5%
permethrin.
What are the prescription drugs used to treat head lice?
Malathion (Ovide *): Malathion has just been reapproved for the
treatment of head lice infestations. When used as directed, malathion is very
effective in treating lice and nits. Few side-effects have been reported.
Malathion may sting if applied to open sores on the scalp caused by scratching.
Therefore, do not use if excessive scratching has caused a large number of open
sores on the head.
Lindane (Kwell*): Lindane is one of the most common treatments
used to treat head lice. When used as directed, the drug is usually safe.
Overuse, misuse, or accidentally swallowing of Lindane can be toxic to the brain
and nervous system. Lindane should not be used if excessive scratching has
caused open sores on the head.
Which head lice medicine is best for me?
If you aren't sure, ask your pharmacist or health care provider.
When using medicine, always follow the instructions.
When treating head lice
- Do not use extra amounts of the lice medication unless
instructed. Drugs are insecticides and can be dangerous when misused or
overused.
- Do not treat the infested person more than 3 times with the
same medication if it does not seem to work. See your health care provider for
alternative medication.
- Do not mix head lice medications.
Should household sprays be used to kill adult lice?
No. Spraying the house is NOT recommended. Fumigants and room
sprays can be toxic if inhaled.
Should I have a pest control company spray my house?
No. Vacuuming floors and furniture is enough to treat the
household.
Other Resources
*Use of trade names is for identification purposes only and does
not imply endorsement by the University of Arkansas Cooperative Extension
Service
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