Transcript Document

Scabies And Pediculosis
Scabies
 Scabies is an itchy rash caused by a little
mite that burrows in the skin surface. The
human scabies mite's scientific name is
Sarcoptes scabiei var. hominis.
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Aetiology
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Scabies is caused by the acarus, Sarcoptes
scabiei, and is a common world-wide public
health problem with an estimated global
prevalence of 300 million. The infestation causes
considerable discomfort and can lead to
secondary infection and complications such as
post-streptococcal glomerulonephritis. Scabies
spreads in households and environments where
there is a high frequency of intimate personal
contact.
Microscopic appearance of Sarcoptes scabiei, the parasite
which causes scabies.
 Sarcoptes
scabiei
Mite and eggs under Microscope
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Scabies
Lesions
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Inappropriate application of scabietic treatments can
cause considerable irritation in other conditions. In small
children the palms and soles can be involved with
pustule formation . Involvement of the genital area in
boys is pathognomonic. The main symptom is itch . The
clinical features include secondary eczematisation
elsewhere on the body; the face and scalp are never
involved except in the case of infants. Even after
successful treatment the itch can continue, and
occasionally nodular lesions persist.
Symptoms and Signs
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Itch
The itching appears a few days after infestation. It may occur within a few hours if the
mite is caught a second time. The itch is characteristically more severe at night and
affects the trunk and limbs. It does not usually affect the scalp.
Burrows
Scabies burrows appear as tiny grey irregular tracks between the fingers and on the
wrists. They may also be found in armpits, buttocks, on the penis, insteps and backs
of the heels. Microscopic examination of the contents of a burrow may reveal mites,
eggs or mite faeces (scybala).
Generalised rash
Scabies rash appears as tiny red intensely itchy bumps on the limbs and trunk. It can
easily be confused with dermatitis or hives (and may be accompanied by these). The
rash of scabies is due to an allergy to the mites and their products and may take
several weeks to develop after initial infestation.
Nodules
Itchy lumps or nodules in the armpits and groins or along the shaft of the penis are
very suggestive of scabies. Nodules may persist for several weeks or longer after
successful eradication of living mite.
Acropustulosis
Blisters and pustules on the palms and soles are characteristic of scabies in infants.
Secondary infection
Impetigo commonly complicates scabies and results in crusting patches and
scratched pustules. Cellulitis may also occur, resulting in localised painful swelling
and redness, associated with fever.
Scabies only rarely affects the face and scalp. This may be the case in young babies
and bedbound elderly patients.
Pruritus :Causes
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Pruritus
Scabies with extensive infestation
of Sarcoptes scabiei.
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scabies
Baby with Scabies Rash
Pustular Eruptions
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Scabies
Scabies in Childhood
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Scabies. Pustules at a common site in a child. Burrows were present but cannot be
seen at this distance
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Affected webspace
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Scabies
Scabies
Diagnosis
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Diagnosis is made by identifying the scabietic burrow, usually found
on the edges of the fingers, toes or sides of the hands and feet.
Extraction of the mite using a blunt needle can be difficult but is
helpful in ensuring the correct diagnosis, appropriate treatment and
compliance. Inappropriate application of scabietic treatments can
cause considerable irritation in other conditions. In small children the
palms and soles can be involved with pustule formation .
Involvement of the genital area in boys is pathognomonic. The main
symptom is itch.
The clinical features include secondary eczematisation elsewhere
on the body; the face and scalp are never involved except in the
case of infants. Even after successful treatment the itch can
continue, and occasionally nodular lesions persist.
Burrows
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Burrows [Arrows point to mites]
Treatment
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Topical treatment of scabies is usual and involves the affected
individual and all asymptomatic family members/physical contacts to
ensure eradication. Two applications one week apart of an aqueous
solution of either permethrin or malathion to the whole body,
excluding the head, is usually successful. In some clinical situations
such as poor compliance, immunocompromised individuals and
heavy infestations (Norwegian scabies), systemic treatment with
ivermectin (200 µg/kg) as a single dose would be appropriate.
25% Benzyl benzoate lotion, applied daily for 3 days
5% Permethrin cream, left on for 8-10 hours
0.5% Aqueous malathion lotion, left on for 24 hours
Successful Treatment
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To reduce the risk of the treatment failing:
Ensure the scabicide is applied to the whole body from
the chin down.
Leave it on for the recommended time and reapply it
after washing.
Apply the scabicide under fingernails using a soft brush.
Obtain antibiotics from your doctor if there is crusting
and secondary infection.
Ensure all close contacts are treated whether or not they
are itchy.
Pediculosis
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Lice
Lice are insects that live on human hair and clothing. They are small but can still be seen with the
naked eye. Often they are well camouflaged and reflect the colour of the surroundings, which
makes them difficult to see.
The medical term for an infection or infestation with lice is called pediculosis.
There are three types of lice that infest humans.
Pediculus humanus var. capitis - The head louse
Pediculus humanus var. humanus - The body louse.
Phthirus pubis - The pubic louse.
Lice are insects than live on rather than in the body. They are wingless and have six legs on which
are attached strong claws, which they use to grasp on tightly to hair shafts or clothing fibres.
Head lice, the most common infestation in humans, are colloquially known as cooties and their
eggs are called nits. Pubic lice are smaller than the other two species, and have a short body
resembling a crab. Hence the name crabs.
Head lice [pediculus humanus capitis]
Body lice [pediculus humanus[corporis]
Pubic lice [phthirus pubis]
Head Lice
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Head lice
Head lice have infested humans for thousands
of years. Infestation with lice is quite often
inappropriately considered related to poor
hygiene and low socio-economic status. In fact
people of all walks of life can get infested with
lice and the stigma of catching lice is often borne
out of ignorance.
Body lice
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Infestation with body lice (Pediculus humanus) is uncommon. They tend to
infest people in extreme states of poverty or personal neglect. Particularly
when clothing is not changed or regular washing is not undertaken.
The eggs of body lice are laid and glued to cloth fibres instead of hair, and
the lice feed off the skin. Regular hot washing of clothes and bathing has
lead to a decrease in incidence of body lice but during wartime and in some
undeveloped countries the condition can still occur.
Body lice in the past have been responsible for spreading diseases such as
typhus. However because of the decline in numbers of people infested with
body lice this is no longer a significant problem.
Similar insecticides used in the treatment of head lice are used in the
treatment of body lice. Hot washing of clothes and bathing should be
emphasised.
Pubic Lice
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Pubic Lice
Pubic lice or crabs are contracted by close contact and are easily
transmitted sexually.
The pubic hair is most common site but lice can spread to other
hairy parts of the body including armpit, beard, chest hair and thigh
hair. Eyelashes can also be affected.
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Pubic louse
Pubic lice infestation results in itching. Blood specks on
underclothes and live lice moving in the pubic hair are occasionally
noted.
Pediculus humanus capitis
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[Head louse]
Phthirus Pubis
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Pubic louse
Pruritic infestation on the Scalp
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Dermatitis
Pediculosis
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Mortality/Morbidity: Morbidity results from the severe itching that is
caused by lice infestation. Mortality may occur from infectious
diseases transmitted by the body louse.
Race: Blacks have a lower incidence of infestation by the head
louse but may experience scalp infestation by P pubis.
Sex: Males and females are equally at risk for infestation.
Age: Lice affect all age groups. Body lice are indiscriminate in
regard to the age of their host. Head lice are common in young
school children but much less common after puberty. Pubic lice
infest body and pubic hair. Prepubescent scalp infestation by P
pubis may occur in individuals with short, thick, curly scalp hair.
Clinical
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History:
Patients may come to the attention of a health care provider after
discovering lice or nits. Parents and teachers typically make the
initial diagnosis of head louse infestation. In the case of head lice, a
school nurse usually discovers infestation, or a generic letter is sent
home to parents indicating that they should inspect their children for
lice.
Pruritus is the most common symptom of infestation. Children often
have trouble sleeping because of intense pruritus at night when lice
are feeding.
Children with infestation may be asymptomatic. Routine nit
inspections by school nurses are standard in many parts of the
United States.
Clinical
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Physical: Manifestations of head louse infestation include scalp pruritus, occipital
lymphadenopathy, and impetigo. Examination of the scalp reveals excoriations, dark specks of
louse dung, nits, and adult lice. The heaviest infestation typically is in the retroauricular scalp.
Pruritus commonly leads to excoriation, secondary bacterial infection, and regional lymph node
enlargement. A generalized exanthem rarely accompanies louse infestation (pityriasis rosealike
pediculid).
Pediculosis capitis: Although head lice may be found on any part of the scalp, they most
commonly are found in the retroauricular scalp. Eggs depend on body warmth to incubate, so nits
are attached to the hair shafts just above the level of the scalp. Human scalp hair grows at a rate
of approximately 0.37 mm/d. Nits found several millimeters from the scalp are nonviable empty
egg cases. They indicate chronic infestation.
Pediculosis corporis: Body lice infest the seams of clothing and take blood meals at night. Nits
are found in the seams, not on human hairs. Maculae ceruleae, the hemosiderin-stained purpuric
spots where lice have fed, suggest the diagnosis of body louse infestation.
Pediculosis pubis: Pubic lice and nits generally are plainly visible throughout the pubic hair,
extending onto adjacent hairy areas of the body. Eyelash nits are a manifestation of pubic louse
infestation, not head louse infestation.
Lab studies
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Lab Studies:
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The identification of adult lice or nits is diagnostic. The presence of bruiselike bites or
dark specks of louse dung suggest the diagnosis of louse infestation.
Lice move rapidly. A helpful technique is to fasten a piece of transparent adhesive
tape to the infested areas. Lice stick to the tape. The tape then becomes a
convenient coverslip for a microscopic slide.
Mature lice are approximately the size of a sesame seed (3-4 mm) with an elongated
body, 3 pairs of legs, and narrow anterior mouthparts. Wide crablike bodies and claws
distinguish pubic lice. Nits are approximately 1 mm in length, transparent, and
flasklike in appearance.
Nits and lice fluoresce with a Wood light.
Properly evaluating persons who have been raped is essential. Evidence should be
collected in such a way as to avoid contamination and to ensure a legal chain of
custody. Human DNA can now be identified in the amount of blood present in a pubic
louse. Lice recovered after an attack have the potential to provide evidence valuable
in securing a convictionOther Tests:
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Evaluate individuals with pubic lice for other STDs. Evaluations may include serologic
testing for syphilis and AIDS, culture for gonorrhea, and antigen testing for chlamydia.
Histologic Findings: Louse bites demonstrate intradermal hemorrhage and a
polymorphous wedge-shaped infiltrate rich in eosinophils
Medical Care
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Medical Care: Reinfestation occurs unless louse infestation is
addressed as a community-wide problem. Management must
include examination of all individuals exposed and treatment of all
those who are infested. Education has been shown to reduce the
number of lice infestations in schools. “No nit” policies exclude many
children from the classroom, but they have not been shown to
reduce the number of lice infestations.
Fomite control is essential. Hats lined up on pegs or placed in
adjacent cubbyholes provide an avenue for spread of the infestation.
Cubbyholes can be sprayed with a permethrin spray or other
insecticide, but the most effective method is for each child to
"ground his or her clothing" (ie, hat, coat, scarves) under each
individual chair or desk. Common cloakrooms may suggest an
antiquated charm, but they should be viewed as merely antiquated
and a site for spread of the infestation.
Combs, brushes, and headbands should not be shared. Shaving of
hair is effective but not socially acceptable in most societies. Young
nits do not have a nervous system and are immune to neurotoxic
pediculicides.
Treatment
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Treatment options include Malathion, permethrin cream, and
pyrethrins. Less toxic agents are being developed that aim to
occlude the respiratory spiracles of the louse and kill via
asphPermethrin (Nix, Elimite) -- DOC recommended by most
authorities. Resistance probably has developed in many areas.
Physicians in some countries select different pediculicides on a
rotating basis to discourage development of resistance. Very
effective in killing adult lice and nymphs but not as effective in killing
nits (eggs). OTC 1% concentration may be insufficient for treatment
of pubic lice and for some cases of head lice. The 5% prescription
preparation marketed for scabies (Elimite) may be more effective in
some cases. One benefit of permethrin is a residual effect in the hair
for several hair wash cycles. yxiation.
Pitfalls
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Medical/Legal Pitfalls:
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Follow manufacturer's instructions for lindane treatment.
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It may not be suitable for use in patients with a defective cutaneous barrier.
Seizure may result from abnormal absorption or gross overuse of the product.
Many authors recommend that it not be used as a first-line therapy.
Pyrethrin products are contraindicated for patients with contact allergy to
ragweed or turpentine.
Failure to recognize that pubic lice in children may be an indication of
sexual abuse is a potential medical/legal pitfall.
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Children with eyelash nits have been exposed to an adult with pubic lice. This is
not proof of abuse, merely an indication that the child has had contact with an
adult with pubic lice.
 Pubic lice commonly infest the adult's body hair, as well as pubic hair.
 Although lice can be transferred easily in the absence of abuse, examine patient
for other signs of abuse
Points To remember
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Important points on treatment for pubic lice
It is important to apply the shampoo to all hairy parts of the body apart from the eyelids and scalp from 'neck to knees'.
It is easily applied while in the shower.
Work thoroughly into lather and leave on for five minutes.
Rinse off thoroughly and dry with a towel.
Any remaining nits (small white spots attached to hair shaft) should be removed by using a fine
toothed comb.
A repeat application is advisable 7 days later.
Shampoo should not be applied near the eyes. Lice and nits can be removed by using a pair of
fine forceps. Alternatively petroleum jelly, such as Vaseline can be smeared on the eyelashes
twice a day for at least 3 weeks.
Wash underwear and bed linen thoroughly in hot water to prevent recurrences.
Sexual partners need to be treated even if they deny itching and do not appear to be infected.
You may be at risk of other more serious sexually transmitted infections. It is advisable to attend
your doctor or sexual health clinic for a check-up.
THANKS
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Please Take Care
Head lice. 'Nits' (empty egg cases) adhere strongly to the hair shafts.