What Are Head Lice?
are small, wingless, blood-sucking insects. They live in the hair on your head
and feed off the blood from your scalp. A louse (a single adult) is about the
size of a sesame seed. A nit (louse egg) is about the size of a small flake of
What Causes Head Lice?
are contagious. You can become infected with head lice when the insects crawl
onto your head. Ways you might get head lice include:
- touching your head to an infected
- sharing the personal items (e.g.,
comb) of someone with head lice
- using a fabric item after an
Lice can be
transferred by brushes, combs, barrettes, headbands, headphones, and hats. They
can also live for a time on upholstered furniture, bedding, towels, or
Who Is at Risk for Head
and elementary school students have the highest risk of getting head lice. They
tend to play closely together and share items that touch their heads. There is
also an increased risk of head lice for family members of school-aged children.
People who work in a day care center, preschool, or elementary school share
What Are the Symptoms of
head lice include:
- extreme scalp itchiness
- feeling like something is
crawling on your scalp
- sores and scabs on your scalp
How Is Head Lice Diagnosed?
You or your
healthcare provider can diagnose head lice by:
- checking your hair, close to the
scalp, for lice
- checking your hair, close to the
scalp, for nits
- running a fine-toothed lice comb
through your hair, starting from the scalp, to catch lice and nits
The nits are dark-colored and hatched lice will be light-colored.
Adult lice move quickly. You will most likely find nits if
you find any evidence of head lice on your scalp.
You can easily differentiate between nits and dandruff
flakes or other debris in your hair. Most debris should be removed easily. Nits
will seem like they are cemented to your hair.
Head lice are contagious. If one person in your household
has them, others may too. It’s a good idea to check everyone (in the household)
for signs of lice every few days.
How Are Head Lice Treated?
There are several head lice treatments
available. Most treatments will need to be used twice. The second treatment,
after a week to nine days, will kill any newly hatched nits.
Some of the major treatments for head lice
are described below.
There are both over-the-counter (OTC) and
prescription head lice treatments.
Two types of chemicals are commonly used in
OTC head lice treatment.
Pyrethrin is a pesticide that is derived from chrysanthemum flowers.
It is approved for use in people 2 years old and older. Do not use pyrethrin if
you are allergic to chrysanthemums or ragweed.
Permethrin (Nix) is a synthetic pesticide that is similar to pyrethrin. It is
approved for use in people 2 months old and older.
Prescription lice treatments may also include
lotion (Ulesfia) is
an aromatic alcohol. It is used to treat head lice in people 6 months old and older.
(Ovide) is an organophosphate pesticide. It is used
to treat lice in people who are 6 years old or older. It is not recommended for
women who are pregnant or breast-feeding. Malathion is flammable. Stay away
from open flames and heat sources such as hair dryers when using this product.
Lindane is an organochloride pesticide. It is available in lotion or
shampoo forms. Lindane is usually only used as a last resort. It can cause
serious side effects, including seizures and death. Lindane should not be used
by premature babies or by people who have a history of seizures.
In order to reduce the risk of side effects:
- Do not use more than one
- Do not use any medication more
often than directed.
If you want to avoid using pesticides, use a
fine-toothed lice comb or a flea comb (sold in pet stores) to remove lice.
Apply olive oil to your hair before combing. This will help the lice and nits
stick to the comb. Start combing at the scalp and work through the end of the hair.
You will need to do this every two to three
days until you have no more signs of lice or nits.
Treating Your Home
There is no
need to use pesticides around your home. Lice cannot survive more than a couple
of days off your head. The following methods can be used to kill lice on
- wash clothes and bedding in hot
water (130 degrees Fahrenheit or above) and dry on high heat in the dryer
- dry-clean clothes and bedding
- seal clothes, bedding, and plush
toys in a plastic bag for two weeks
- soak hair brushes, combs,
barrettes, and other hair accessories in hot water (130 degrees Fahrenheit) for
five to 10 minutes
- vacuum floors and upholstered
You can get rid of head lice with the proper
treatment. However, you may become reinfected. Reduce that risk by cleaning
your house properly and avoiding contact with other infected people until they
have been treated.
You can reduce your chances of getting head
lice by not sharing personal hygienic items with others.