Pediculosis, head lice, head lice infestation

WISCONSIN DIVISION OF PUBLIC HEALTH
Department of Health and Family Services
Pediculosis
(head lice infestation)
What is pediculosis (head lice)?
Pediculosis is an infestation of head lice on the hair of the head. The lice feed on human blood which can cause severe local itching.
Who gets pediculosis?
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 carecenters, 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 lice-carrying objects such as combs, brushes, hats or scarves.
Since nits (louse eggs) must be laid by adult lice, the chances of nits being spread fromperson-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 forlouse nits (eggs). Severe scratching may result in secondary bacterial infection in theseareas. 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 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 How long do head lice live away form 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 individuals and their belongings, especially DEVELOPED BY THE DIVISION OF PUBLIC HEALTH, BUREAU OF COMMUNICABLE DISEASE
COMMUNICABLE DISEASE EPIDEMIOLOGY SECTION.
PPH 72078 06/01
clothing, headgear, brushes, combs and bedding. Combs and brushes used oninfested persons should be immersed in hot water (>130o ), Lysol®, rubbing alcohol or alice-killing chemical for 1 hour. Floors, rugs, pillows and upholstered furniture should bethoroughly vacuumed, and the vacuum bag discarded when complete. Clothing,linenand cloth toys worn or handled by an infested individual within 2 days of beingdiagnosed with head lice should be washed in hot water (>130o F) or machine dried atthe hottest setting for 20 minutes. Other articles may be dry cleaned or sealed in plasticbags for at least 10 days to destroy lice and eggs. In addition, parents should performregular 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 theenvironment with lice-killing chemicals is not recommended.
What is the treatment for pediculosis?
There are several medicated shampoos commonly used to treat head lice.
Shampoos or creme rinses that contain 1% permethrin have the fastest killing timeagainst adult lice and the highest nit-killing capability. Permethrin has a residual effectthat will continue to kill nits for several days after the first application. While oneapplication should be sufficient to kill lice and nits, some experts suggest a secondtreatment one week after the first. Although resistance to permethrin has been reportedfrom other countries, no resistance has been reported in the United States.
Shampoos which 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 thesetypes of shampoos 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 nitkilling capability. Lindane is not recommended for young children, or pregnant ornursing women, and should only be used if other approved therapies did not work orcannot be tolerated. Misuse or overuse of lindane may be toxic. There are widespreadreports 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 beused with discretion for those persons for whom lice-killing medications have failed.
The effectiveness of alternate treatments is unclear. Kerosene, gasoline and otherflammable products should never be used to treat head lice. Avoid using powder toremove alternate treatments from the hair. Grease cutting shampoos or dish soap maybe used to remove alternate treatment. Avoid wearing plastic wrap and shower capswhen using lice-killing medication. Lice-killing medications have not been safety-testedfor use with plastic wrap or shower caps. Such devices should never be used on youngchildren, and used with discretion on older children and adults when alternatetreatments 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 alternatetreatments. To aid in the removal of nits, hair can be soaked in a 3% to 5% whitevinegar solution followed by application of a damp towel soaked in the same solution for30-60 minutes before attempting nit removal.
DEVELOPED BY THE DIVISION OF PUBLIC HEALTH, BUREAU OF COMMUNICABLE DISEASE
COMMUNICABLE DISEASE EPIDEMIOLOGY SECTION.
PPH 42078 06/01

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