Infectious Diseases Curriculum INSTRUCTOR’S MANUAL
A program of the American Academy of Pediatrics
Quick reference sheets • • • 95
Lice (Pediculosis Capitis)
What are head lice?
Small, tan-colored insects (less than ¹/• 8"long)that
Live on blood they draw from the scalp. ~
Live for days to weeks depending on temperature ~
and humidity.
Crawl. (They do not hop or fly.) ~
Deposit tiny, gray/white eggs, known as ~ nits, on a hair
shaft 3 to 4 mm from the scalp because the eggs need the
warmth from the scalp for hatching.
Cannot live for more than 48 hours away from the scalp ~
as adult insects, and as eggs, cannot hatch at tempera-
tures lower than those found close to the scalp.
Having an infestation with lice may cause irritation and •
scratching, which can lead to secondary skin infection.
Families and caregivers/teachers often get very upset about •
lice; however, head lice do not carry disease. Head lice
infestations occur in all socio-economic groups and do not
represent poor hygiene.
Often, normal activities are disrupted because people •
become so upset about these insect pests.
What are the signs or symptoms?
Itching of skin where lice feed on the scalp or neck or com-•
plaints about itchiness by older children.
Nits may be glued to hair, most easily seen behind ears and •
at or near the nape of the neck.
Scratching, especially behind and around ears and at the •
nape of the neck.
Open sores and crusting from secondary bacterial infection •
that may be associated with swollen lymph nodes (com-
monly called swollen glands).
What are the incubation and contagious periods?
Incubation period: 10 to 14 days from laying to hatching •
of eggs.
Lice can reproduce 2 to 3 weeks after hatching. ~
Contagious period: Until lice are killed with a chemical •
treatment.
How are they spread?
Direct contact with infested hair. •
Only lice, not nits, spread the infestation. (Nits must be •
near a warm scalp to hatch.)
How do you control them?
By using medications (pediculocides) that kill lice and •
nits. Resistance of lice and nits to these chemicals has been
reported, but the extent of resistance to the chemicals var-
ies. Some chemicals may require 2 treatments. Since the
chemicals are toxic, they should be used according to the
approved instructions only. If a particular chemical fails to
work, repeated use of that chemical is unlikely to be suc-
cessful, and an alternative chemical that has been shown
to be effective should be tried.
None of the suggested remedies using common household •
products(eg,saladoils,mayonnaise,petroleumjelly)or
chemicals intended for other purposes have been shown to
be effective. Some that have been tried (eg, kerosene) are
very dangerous.
Mechanical removal of the lice and nits by combing them •
outwithaspecialne-toothcombistediousandverytime-
consuming.
Have families examine the heads of household and •
close contacts.
Infested articles that can be laundered should be cleaned at •
130°F (54.4°C) and dried on the hot setting. Dry-cleaning
clothing and bedding, or separating them from contact with
people also is effective.
continued
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Child with nits on hair behind ears and at nape of neck
EDGAR K. MARCUSE, MD
MIDCCS.indb 95 8/15/08 1:26:08 PM
The recommendations in this publication do not indicate an exclusive course of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate. Original document included as part of Managing
Infectious Diseases in Child Care and Schools: A Quick Reference Guide opyright American Academy of Pediatrics A ights esered he American Academy of Pediatrics does not reie or endorse any modications made to this docment and in
no event shall the AAP be liable for such changes.
Aronson SS, Shope TR. Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide. 2nd ed. Elk Grove Village, IL: American Academy of Pediatrics; 2009
Available at www.aap.org/bookstore
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