White Paper – Head Lice

Just the mere thought of head lice can begin to
make us itch. Unfortunately, lice do not only
infect a certain population. Any person is at
risk of becoming infested, whether you have
clean or dirty hair. Head lice are parasitic insects
found mostly in hair on the head. However, they
can also spread to the eyebrows and eyelashes as
well. The itching most commonly associated with
lice, is actually an allergic reaction to their bites.
Other common symptoms include: a tickling
feeling, sleeplessness due to increased activity
of lice at night, and sores on the head.

There are 3 stages in the lice life cycle. They
begin as nits (eggs), hatch into nymphs, then
mature into adults. The nits are cemented to the
hair shaft close to the scalp and appear white or
yellowish in color. They are commonly mistaken
as dirt, dandruff, or even hair spray droplets.
After about 6-9 days, nymphs hatch. These will
mature to adults in about a week’s time. As
adults, female lice can lay up to 8 nits per day
with a lifespan around 30 days. Removed from
the head, lice can only survive about 1-2 days
without feeding.

In recent years, treatment resistant lice have
become a bigger problem. These are lice that
have become exposed to the pediculicide (lice
killing treatment), but for one reason or another,
are not killed. These lice begin to develop and
pass on mutations to new nits. Each time a
louse is exposed to medication, but is not
killed, it is given the chance to develop
resistance. Thus a vicious cycle has begun. These
lice are then spread to other people, either
through close contact or sharing combs, brushes,
helmets, towels, etc. When the newly infected
individuals try to treat with the same product
it will either be less effective or have no effect
at all. The best way to prevent the development
and spread of these resistant lice is to treat lice
correctly to begin with. Here are some helpful
tips for treatment:

  • Most importantly, make sure you use the
    product as instructed on packaging or as
    directed by a healthcare provider.
  • Apply liberally all over the hair, especially the
    roots, scalp and neck.
  • Lather & rinse off after 10 minutes.
  • Use a fine toothed comb to help remove the
    lice & eggs.
  • Repeat treatment after 7-10 days if indicated.
  • Do not use conditioner or a shampoo-conditioner
    combination product before treatment.
    Conditioner can prevent the medication from
    adhering to the hair shaft.
  • Avoid washing hair for 1-2 days after treatment,
    to prevent medication from washing out of
    the hair.
  • Rechecking for lice and nits every 2-3 days for
    about 3 weeks after treatment will help to
    continually remove new lice that have hatched
    and prevent reinfection.
  • Soak hair brushes and combs in very hot water
    for at least 5-10 minutes.
  • All clothing and bedding should be washed
    with the hottest setting and dried on the high
    heat setting.
  • Vacuum furniture and flooring.
  • Anything that cannot be washed or vacuumed
    sufficiently can be stored in a plastic bag for
    2 weeks.
  • The entire family should probably be treated,
    especially if you are unsure how long the
    individual has been infected

If you have treated the lice and later find you
have lice again, there could be a couple of causes.
Either you were reinfected or the lice were never
completely removed the first time. You can use
an OTC product again to see if this works. You
must also find out where the lice are coming
from. Some possibilities include:

  • Is there someone in daycare or school that
    could be passing it on?
  • Have you shared combs, hairbrushes, hats,
    helmets, clothing, etc. with someone else?
  • Were all clothing, combs, brushes, bedding,
    flooring, furniture and stuffed animals
    properly cleaned?
  • Does your child ride the bus or have friends
    they hang out with after school?
    You do not want to use the same product more
    that 2-3 times. If you have tried 2 rounds of
    treatment with the OTC products and are still
    experiencing problems talk to a healthcare
    provider. There are some prescription options
    available. These are usually more expensive,
    but also more effective.
  • Product: NIX
    Ingredients: Permethrin
    Prescription or OTC: OTC
    Ages: Approved for those
    >2 months of age
    Is retreatment needed? Recommended around 7-10 days to kill newly hatched nymphs
  • Product: RID
    Ingredients: Pyrethrins, Piperonyl Butoxide
    Prescription or OTC: OTC
    Ages: Approved for those
    >2 years of age
    Is retreatment needed? Recommended around
    7-10 days to kill newly
    hatched nymphs
  • Product: Sklice
    Ingredients: Ivermectin
    Prescription or OTC: Prescription
    Ages: Approved for those
    >6 months of age
    Is retreatment needed? Not needed

Christine Hashman
PharmD Candidate 2016