Pediculosis capitis Pediculosis corporis Pediculosis pubis Three types of lice: Head lice: Pediculus humanus capitis (2-3 mm long) Body lice: Pediculus humanus humanus (2.3-3.6 mm long) Pubic lice (crabs): Phthirus pubis (1.1-1.8 mm long) Sites of predilection Head lice nearly always confined to scalp, especially occipital and postauricular regions. Rarely, head lice infest beard or other hairy sites. Although more common with crab lice, head lice can also infest the eyelashes ( pediculosis palpebrarum ).

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Pediculosis

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Epidemiology And Etiology
Etiology :
Lice

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Three types of lice:
• Head lice: Pediculus humanus
capitis (2-3 mm long)
• Body lice: Pediculus humanus
humanus (2.3-3.6 mm long)
• Pubic lice (crabs): Phthirus
pubis (1.1-1.8 mm long)

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Head Lice Body Lice Pubic Lice

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Transmission
Direct contact between individuals.
Indirect contact with bedding, brushes, or
clothing, according to species.
 Pediculosis and scabies may coexist in
the same individual

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Secondary Infections of Excoriated
Sites
Excoriation may become secondarily
infected with S. aureus , GAS.
Infection can extend, resulting in cellulitis,
lymphangitis, and/or bacteremia

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Clinical Manifestation
• Pruritus occurs in a variable
proportion.
• Excoriations can become secondarily
infected.

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Management
• Topically Applied Insecticides :
Ideally, should have 100% activity against louse and egg.
• Malathion kills all lice after 5 min of exposure, and
>95% of eggs fail to hatch after 10 min of exposure.
• Permethrin are synthetic pyrethoids widely
used as insecticide, araricide, and insect repellant.
• Lotion preparations are preferred; creams, foams, gels
are also available.

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Management
Recommended Regimen :
1. Permethrin:
• Nix : Over-the-counter 1% product
• Elimite : 5% product by prescription.
• Product applied to infested area(s) and
washed off after 10 min. Incubation period
of louse eggs is 6–10 days; reapply in 7–
14 days.

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Management
Recommended Regimen :
 2. Pyrethrin and piperonyl butoxide (PBO):
PBO is a synergist of pyrethrin. Kills mites
louse and egg.
• Preparations: liquid, gels, shampoos.

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Management
Recommended Regimen :
3. Malathion:
 0.5% in 78% isopropyl alcohol(Ovide). Applied
to involved site for 8–12 h; binds to hair
providing residual protection.
 Indicated in lindane -resistant cases.
 Should not be used in children younger than 6
months.

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Management
Alternative Regimen :
1. Pyrethrins with PBO :
Applied to scalp and washed off after
10 min.

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Management
Alternative Regimen :
2. Lindane 1% shampoo :
• Applied for 4 min and then thoroughly
washed off.
• (Not recommended for pregnant or
lactating women.)

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Management
Alternative Regimen :
3. Ivermectin :
0.8% lotion or shampoo.

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Management
• Systemic Therapy:
Oral ivermectin : 200 μg/kg; repeat
on day 10 to kill emerging nymphs.
• oral ivermectin in cases of resistance
to both pyrethroids and malathion

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Pediculosis may be divided into the
following types :
1)Pediculosis capitis
2)Pediculosis corporis
3)Pediculosis pubis
Pediculosis

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• An infestation of the scalp by the head
louse.
• Feeds on scalp and neck and deposits its
eggs on hair.
Pediculosis Capitis

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Epidemiology And Etiology
• Etiology :
The subspecies Pediculus humanus capitis

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Epidemiology And Etiology
• Sex, Age of Onset:
Girls > boys. 3–11 years, but all ages.
• Race:
In United States, more common in whites
than blacks

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Transmission
1) Head-to-head contact.
2) Shared hats, caps, brushes, combs;
theater seats; pillows.
3) Epidemics in schools; classrooms are the
main source of infestations.
4) Head lice can survive off the scalp for up
to 55 h.

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Predisposing Factors
• School-age children and their mothers.
• More common in warmer months.

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Sites of predilection
• Head lice nearly always confined to scalp,
especially occipital and postauricular
regions.
• Rarely, head lice infest beard or other
hairy sites. Although more common with
crab lice, head lice can also infest the
eyelashes ( pediculosis palpebrarum ).

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Clinical Manifestation
Skin Symptoms:
 Pruritus of the back and sides of scalp.
 Scratching and secondary infection associated
with occipital and/or cervical lymphadenopathy.

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Skin Lesions
Bite reactions : at site of louse bites apparent
on neck. Phases related to immune sensitivity/
tolerance:
Phase I: no clinical symptoms.
Phase II: papular urticaria with moderate
pruritus.
Phase III: wheals immediately following bite
with subsequent delayed papules/intense
itching.
Phase IV: smaller papules with mild pruritus.

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Eczema , excoriation , lichen simplex
chronicus on occipital scalp and neck
secondary to chronic scratching/rubbing

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• Secondary impetiginization with S. aureus of
eczema or excoriations; may extend onto neck,
forehead, face, ears.
• Confluent, purulent mass of matted hair, lice,
nits, crusts, and purulent exudation in extreme
cases.
• Pediculid is a hypersensitivity rash, resembling
a viral exanthem.
• Wood lamp : Live nits fluoresce with a pearly
fluorescence; dead nits do not.

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Pediculosis capitis: multiple nits
on scalp hair

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Diagnosis ?
1) Clinical Diagnosis (Skin lesion )
2) Laboratory Examinations :
• Microscopy : The louse or a nit
on a hair shaft
• Cultures :. If impetiginization is suspected
, bacterial cultures should be obtained.

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Management
1. Fomite/Environmental Control :
 Avoid contact with possibly contaminated items such as
hats, headsets, clothing, towels, combs, hair brushes,
bedding, upholstery.
 The environment should be vacuumed.
 Bedding, clothing, and head gear should be washed
and dried on the hot cycle of a dryer.
 Combs and brushes should be soaked in rubbing
alcohol or Lysol 2% solution for 1 h.
 Families should look for lice routinely.

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2.Pediculocide Therapy
• Topically Applied Insecticides :
Ideally, should have 100% activity against louse and egg.
• Malathion kills all lice after 5 min of exposure, and
>95% of eggs fail to hatch after 10 min of exposure.
• Permethrin are synthetic pyrethoids widely
used as insecticide, araricide, and insect repellant.
• Lotion preparations are preferred; creams, foams, gels
are also available.

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Management
Recommended Regimen :
1. Permethrin:
• Nix : Over-the-counter 1% product
• Elimite : 5% product by prescription.
• Product applied to infested area(s) and
washed off after 10 min. Incubation period
of louse eggs is 6–10 days; reapply in 7–
14 days.

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Management
Recommended Regimen :
 2. Pyrethrin and piperonyl butoxide (PBO):
PBO is a synergist of pyrethrin. Kills mites
louse and egg.
• Preparations: liquid, gels, shampoos.

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Management
Recommended Regimen :
3. Malathion:
 0.5% in 78% isopropyl alcohol(Ovide). Applied
to involved site for 8–12 h; binds to hair
providing residual protection.
 Indicated in lindane -resistant cases.
 Should not be used in children younger than 6
months.

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Management
Alternative Regimen :
1. Pyrethrins with PBO :
Applied to scalp and washed off after
10 min.

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Management
Alternative Regimen :
2. Lindane 1% shampoo :
• Applied for 4 min and then thoroughly
washed off.
• (Not recommended for pregnant or
lactating women.)

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Management
Alternative Regimen :
3. Ivermectin :
0.8% lotion or shampoo.

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Management
• Systemic Therapy:
Oral ivermectin : 200 μg/kg; repeat
on day 10 to kill emerging nymphs.
• oral ivermectin in cases of resistance
to both pyrethroids and malathion

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Pediculosis Corporis
• In body louse infestations, lice reside and
lay eggs in clothing.
• Leave clothing to feed on human host .
• Body louse survive more than a few hours
away from the human host.
• Occurs in poor socioeconomic conditions.

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Epidemiology And Etiology
Etiology :
Pediculus humanus humanus.

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Risk Factors :
1. Poor socioeconomic conditions.
2. when clothing is not changed or washed
frequently: poverty, war, natural
disasters, indigence, homelessness,
refugee-camp populations.

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Clinical Manifestation

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Pediculosis corporis Severely malnourished, ill-kept, homeless
male with multiple excoriations, erosions and crusted papules, and
nodules and eczematized lesions. Lice and nits are seen in the
seams of clothing (inset).

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Diagnosis :
Lice and eggs are found in clothing
seams.

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Management
• Bedding and clothing must be
systematically decontaminated.
• Hygiene Measures : Basic sanitation
measures, and hygiene measures to
assure changes of clean clothing, body
washing, and sometimes shaving.

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Management
• Delousing:
 Pyrethrins / pyrethroids or malathion for 8–24 h
is recommended in some cases.
 Outbreaks necessitate delousing of individuals
with 1% permethrin dusting powder .
• Louse-Borne Infections: Antibiotics are
indicated if louse-borne infectious disease
(trench fever, epidemic typhus) exists.

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Pediculosis Pubis (Pthiriasis)
Crabs
 Sexually transmitted disease.
 Pediculosis pubis is an infestation of hair-bearing
regions:
▪ Most commonly the pubic area
▪ Hairy parts of the chest and axillae
▪ Upper eyelashes.
 Manifested clinically by mild to moderate
pruritus, papular urticaria, and excoriations.

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Epidemiology And Etiology
• Age :Most common in young adults;
range, from childhood to senescence.
• Sex: More extensive infestation in males.
• Etiology :
Pthirius pubis

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Transmission
1) Close physical contact: sharing bed;
possibly exchange of towels.
2) Sexual exposure. May coexist with
another sexually transmitted infection
(STI).
3) Nonsexual transmission: homeless
persons who have pubic lice in hair on
head and back.

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 Often asymptomatic.
 Mild to moderate pruritus for months.
 Patient may detect a nodularity to hairs (nits or
eggs) while scratching.
 With excoriation and secondary infection, lesions
may become tender and be associated with
enlarged regional, e.g., inguinal, lymph node.
Clinical Manifestation

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Skin Lesions
• Papular urticaria (small erythematous papules) at
sites of feeding, especially periumbilical ; blisters.
.

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• Secondary infection: detected in patients
with significant pruritus.
• Maculae ceruleae ( taches bleues ): are
slate-gray or bluish-gray macules 0.5–1 cm in
diameter, irregular in shape, nonblanching.
Pigment thought to be breakdown product of
heme affected by louse saliva.

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• Eyelash infestation :
Serous crusts may be present along with
lice and nits , occasionally, edema of eyelids
with severe infestation.

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Laboratory Examinations
• Microscopy Lice (Fig.) and nits may be identified
and differentiated from head/body louse with hand lens
or microscope.
• Cultures Bacterial cultures if excoriation
impetiginized.
• Serology Sexually transmitted. Testing for other STIs
may be indicated in some individuals.

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Management
1. Prevention:
Patient and sexual partners should be
treated.
2. Pediculocides :
see before

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• SOURCE: From FITZPATRICK’S COLOR ATLAS
AND SYNOPSIS OF CLINICAL DERMATOLOGY
SIXTH EDITION

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