Head Lice - Pediculosis
General information
Pediculosis
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What is pediculosis (head lice)?
Pediculosis is an infestation of head lice on the hair of the head. The
lice feed on human blood. This can cause severe local itching.
Who gets pediculosis (head lice)?
Anyone may become infested with head lice, regardless of age, sex, race,
or standards of personal hygiene. Head lice are frequently found in
schools and day care centers, and are easily spread from person to
person.
How are head lice spread?
Head lice are spread through direct head-to-head contact with an
infested person or indirect contact with an infected person or
lice-carrying objects such as combs, brushes, hats or scarves. Since
nits (louse eggs) are laid by adult lice the chances of nits being
spread from person to person are minimal.
Do animals spread head lice?
No. Lice from animals do not infest humans.
What are the symptoms of pediculosis?
The first indication of an infestation is usually itching at the back of
the head and around the ears. Itching in these areas should lead to an
examination of the scalp for louse nits (eggs). Severe scratching may
result in secondary bacterial infection in these areas. Head lice do not
carry or spread disease.
How soon do symptoms appear?
It may take 2 to 3 weeks for a person to notice the intense itching
associated with pediculosis.
How long is a person able to spread head lice?
Lice can be spread as long as they remain alive on the infested person
or their clothing.
How long do head lice live away from the body?
Unattached to the body and without a blood meal, head lice survive for
approximately 6-24 hours (averaging about 12-15 hours).
What can be done to prevent the spread of head lice?
- Avoid physical contact with infested people and their belongings,
especially clothing, headgear, brushes, combs and bedding.
- Combs and brushes used on infested people should be immersed in
hot water (>130ºF), Lysol®, rubbing alcohol or a lice-killing
chemical for 1 hour.
- Floors, rugs, pillows and upholstered furniture should be
thoroughly vacuumed, and the vacuum bag discarded.
- Clothing, linen and cloth toys worn or handled by an infested
person within 2 days of being diagnosed with head lice should be
washed in hot water (>130 ºF) or machine-dried at the hottest
setting for 20 minutes.
- Other articles may be dry-cleaned or sealed in plastic bags for at
least 10 days to destroy lice and eggs. In addition, parents should
perform regular lice checks on the scalp of children who attend
school and day care centers, especially when excessive itching is
noticed.
Fogging with insecticides or spraying the
environment with
lice-killing chemicals is not recommended.
What is the treatment for pediculosis - head lice?
There are several medicated shampoos commonly used to treat head lice.
Shampoos or cream rinses that contain 1% permethrin have the fastest
killing time against adult lice and the highest nit-killing capability.
Permethrin has a residual effect that will continue to kill nits for
several days after the first application. While one application should
be sufficient to kill lice and nits, some experts suggest a second
treatment one week after the first. Although resistance to permethrin
has been reported from other countries, no resistance has been reported
in the United States.
Shampoos that contain pyrethrin kill lice quickly but do not leave a
residual that will continue to kill nits, resulting in a less effective
treatment. Two applications of these types of shampoo 7-10 days apart
are recommended to kill nits.
Shampoos containing malathion and lindane are available by
prescription only. Lindane has the slowest killing time for head lice
(up to several hours) and lowest nit killing capability. Lindane is not
recommended for young children, or pregnant or nursing women, and should
only be used if other approved therapies did not work or cannot be
tolerated. Misuse or overuse of lindane may be toxic.
There are widespread reports from countries other than the United
States of lice being resistant to lindane.
Alternate treatment methods such as the use of tub butter or
margarine, mayonnaise, Vaseline® and olive oil, designed to smother
head lice and nits, can be used with discretion for those persons for
whom lice-killing medications have failed. The effectiveness of
alternate treatments is unclear.
Kerosene, gasoline and other flammable products should never be used
to treat head lice. Avoid using powder to remove alternate treatments
from the hair. Grease-cutting shampoos or dish soap may be used to
remove alternate treatment. Avoid wearing plastic wrap and shower caps
when using lice-killing medication. Lice-killing medications have not
been safety-tested for use with plastic wrap or shower caps. Such
devices should never be used on young children, and used with discretion
on older children and adults when alternate treatments are used.
Manual removal of nits with a nit comb, fingernails, or by cutting
strands of hair that contain nits is essential following treatment with
pediculocides or alternate treatments. To aid in the removal of nits,
hair can be soaked in a 3% to 5% white vinegar solution followed by
application of a damp towel soaked in the same solution for 30-60
minutes before attempting nit removal.
Contacts
Wisconsin
Local Health Departments - Regional Offices - Tribal Agencies
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Last Revised: May 01, 2012 |
