SCABIES

SCABIES
OUTLINE
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What is scabies
Scabies mite
Lifecycle of the scabies mite
How long are people infectious
Symptoms
Areas of scabies infestation
Appearance of scabies
Differences to other skin conditions
Treatment
Other advice – bedding and clothing
Itching and treatment
Companion products
What is scabies?
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Scabies is an infestation caused by the
microscopic mite (Sarcoptes scabiei)
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It is found worldwide and affects people of all
races and social classes – it is NOT associated
with a lack of hygiene
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Scabies spreads rapidly in conditions where
there is frequent skin-to-skin contact between
people, such as aged care facilities, childcare
centres, backpacker hostels and residential
facilities
Scabies mite
Lifecycle of the scabies mite
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The female mite, which is only a few millimetres
long, is transmitted onto the skin and then
burrows into the top layer of the skin with jaws
and first two pairs of legs
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She lays her eggs into the tunnel that is formed
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Faecal matter from the mite is also left in these
tunnels
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The eggs hatch into larvae and grow to adult
after 10 to 14 days
Lifecycle of the scabies mite
After several days,
the larvae hatch,
form burrows,
develop into adults
and travel back up to
the surface of the
skin
 Adults copulate and
the impregnated
female begins a new
life cycle
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Lifecycle of the scabies mite
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Organisms multiply to dozens in 2-3 weeks
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Female mites live for about two months, laying
three eggs a day and travel up to three
centimetres a minute
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Mites live in skin and are not shed easily
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Mites survive away from the human host (e.g.
on bed sheets) only for 12-24 hours or less
Lifecycle of the scabies mite
Scabies mite and larvae
in skin epidermis
Symptoms of scabies
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The main symptoms are:
 pimple-like irritations, burrows and/or rash of
the skin - especially the webbing between the
fingers, the penis, the breast, or shoulder
blades, and the skin folds on the wrist, elbow,
or knee – the head and neck are not affected
 intense itching, especially at night and over
most of the body
 sores on the body caused by scratching these sores can sometimes become infected
by bacteria.
Symptoms of scabies
The burrows or tunnels are visible to the naked
eye although they can be faint and difficult to
see
 They can also be completely obscured by the
patient scratching over the area
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burrow
Magnified burrow
Normal hand – no magnification
Symptoms of scabies
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Symptoms only appear one month after
infestation
This is because the itching and rash are due to
an immune or allergic reaction from either the
presence of the mite itself or the faecal mater
that it leaves in the burrows or tunnels
The immune reaction may kill mites but
sufficient numbers remain to stay contagious
The itching may persist days to weeks even
after successful scabies treatment
Reinfection in pre-exposed persons will produce
rash in 2-3 days because the body “remembers”
the allergens of mite and faecal matter
How long are people
infectious with scabies?
People are infectious for about 1 month before
the itching appears
 People with scabies can pass on the scabies
mite until the day after they have commenced
their treatment for scabies
 Thus child care facilities and people who have
had contact with that person during these times
should be advised to watch for symptoms and
treat accordingly
 The scabies mite can live for two to three days
on the clothes, bed linen and other personal
items of people who have scabies
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Area of scabies infestation
Scabies appearance
Scabies in skin folds under breast
Scabies in between fingers
Scabies appearance
Scabies on wrist
Scabies on back of hand
Scabies appearance
Scabies that have become infected by excessive skin scratching
Can scabies look like other
skin diseases
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Even experienced doctors will miss the
diagnosis of scabies at least once
Skin conditions that may be confused with
scabies include:
 Dermatitis or eczema
 School sores (impetigo)
 Insect bites
Differences in skin conditions
Differences between various skin conditions and scabies
Condition
Itching
present
Area
affected
Family
history
Onset
Other
indications
Scabies
yes especially at
night
Wrists, between
fingers, skin folds
No but other
contacts may get
it at same time
Sudden
Burrows on close
examination
Eczema
yes especially at
night
Head and scalp,
neck, inside of
elbows, behind
knees, and
buttocks
Usually – may
also have asthma
Early age
Dry skin
School sores
Area sore or
tender but not
itchy
Usually nose,
mouth and
exposed areas of
legs and arms
No
Sudden
Sores enlarge
quickly
Insect bites
Yes
Exposed areas
No
After outdoor or
unscreened
exposure
Bites if scratched
scab over and
heal quickly
How do you get scabies?
Scabies is transmitted by direct, prolonged,
skin-to-skin contact with a person already
infested with scabies - contact must be
prolonged (a quick handshake or hug will
usually not spread infestation)
 Infestation is easily spread to sexual partners
and household members
 It is also spread by sharing clothing, towels, and
bedding (eg children sleeping over with a child
who already has scabies)
 Anyone can get scabies regardless of age, sex,
race or standards of personal hygiene
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Scabies treatment
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Treatment of scabies is with:
Permethrin 5%
 (in Lyclear Cream, Quellada Scabies lotion)
 Permethrin is the active ingredient of choice in
Australia because of its effectiveness and low
toxicity
 Lyclear is available on the Pharmaceutical
Benefits Scheme but not Quellada
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Benzyl benzoate 25%
 (in Ascabiol, Benzemul)
 Benzyl benzoate is a irritant to the skin and must
be diluted in children
Scabies treatment
Scabies treatment – Lyclear
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Application of Lyclear
 All over application of Lyclear kills mites in
their burrows. It contains no colour agent and
no perfume, it is odourless and absorbed
completely into the skin leaving no residue.
Lyclear is completely effective in 91% of
infestations after only one application
Scabies treatment – Lyclear
and Quellada
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Application of Lyclear and Quellada
 Before application, make sure the skin is
clean, cool and dry
 For adults and children over 2 years:
▪ Apply to the whole body from the neck down,
rubbing lightly into the skin until it disappears
▪ Don't forget to cover all skin surfaces, including
between the fingers and toes, palms, under the
nails, on the soles of the feet as well as wrists,
buttocks and genitals
Scabies treatment – Lyclear
and Quellada
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For babies over 6 months to 2 years,
apply also to the face, neck, ears and
scalp, avoiding only the areas immediately
around the eyes and mouth
Antiscratch mittens may be useful to
prevent the cream being sucked off the
fingers
Scabies treatment – Lyclear
and Quellada
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Duration of treatment
 Leave the cream on for at least 8 hours before
washing off with soap and water, but no longer
than 24 hours
 Ideally, apply the cream before going to bed
and wash off in the shower the next morning
 If applied during the day, reapply to any area
which may be washed during the 8 hour
treatment time
Scabies treatment – Ascabiol,
Benzemul
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Because of the potential for skin irritation,
benzyl benzoate should always be patch tested
on the skin to see if any irritation develops
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Ascabiol and Benzemul 25% preparations
should be diluted for children less than 2 years
of age (dilute with 3 parts water) and for children
2 to 12 years of age and adults with sensitive
skin (dilute with equal parts water)
Scabies treatment – Ascabiol,
Benzemul
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After a bath, apply a thin layer to the cool dry
skin of the whole body from the neck down
using a soft brush
Allow to dry
Leave on for 24 hours then wash off
A second treatment after 5 days is only needed
if live mites are present
Ascabiol recommends scrubbing the body down
with a brush after the bath to open up the
burrows and allow better access of the product
to the mites
Other advice – bedding and
clothing
All bed linen and clothes should be changed
and washed (wash with hot water this kills the
mite and its eggs)
 Dry cleaning, ironing, or hot clothes drying are
also effective.
 Any clothing or bedding that can’t be washed
should be put aside for 7 days before using (eg
placed in a plastic bag). The mite and eggs will
die during this time
 The treatment of all household members is often
repeated at 7-10 days to maximise chance of
eradication of the infestation
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Itching with scabies
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Itching
 The itching is due to the immune allergic
reaction which presents about 1 month after
being first infected
 Itching with scabies is intense especially at
night
 The itching may persist even after application
of scabicides – however it should begin to
fade 2-3 days after treatment
 Scabicides should not be reapplied while
itching persists – it only irritates further
Treatment of itching
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Patients may need a product to control the itching:
 Sedating antihistamines (Phenergan, Polaramine,
Dozile, Restavit)
▪ These products reduce the allergic response and may
control the itching. The sedative quality may also help the
patient sleep if the itching is keeping them awake
▪ Be aware of drowsiness during the day and the affect on
alertness
 Topical corticosteroids (Dermaid 0.5% and 1% cream,
Sigmacort 1% cream)
▪ Topical corticosteroids may reduce the inflammation and
redness associated with itching
▪ Systemic absorption can occur in young children especially if
applied to large surface areas
Treatment of itching
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Eurax (crotamition)
 While Eurax has been used to treat scabies,
studies done in the US found that it was
almost one-third of the effectiveness of
permethrin
 However, it does have some anti-itch
properties and may be helpful when applied to
patients with itchy skin
 It is no longer used as an effective antiscabies treatment
Companion Products
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Because the scabies rash could be
classified as an irritant dermatitis, the
inflamed skin would benefit from products
that would soother and moisturise the
skin. Treatment for scabies can irritate the
skin and moisturisers and soothers would
also be beneficial if this occurs
Pinetarsol (soap, solution, gel)
Moisturisers
 Dermaveen, Aveeno (colloidal oatmeal)
Companion Products
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Moisturisers include:
 Sorbolene and glycerine cream
 Emulsifiable oil baths (Alpha Keri, QV)
 Emusifiable oil baths containing oatmeal
(Dermaveen, Aveeno)
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Anti-itch general products
 Pinetarsol
Companion products
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Emulsifiable oil baths
 Alpha Keri (lotion, wash, cream)and QV
▪ These products contain a non-reactive mineral oil
which will not irritate sensitive skin and which
promotes the absorption of water in the product
Companion Products
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Emulsifiable bath oils with oatmeal
(Aveeno, Dermaveen)
 Oatmeal has had a long history of being used
to relieve itchy skin
 Studies show that oatmeal contains
avenanthramides and phenols, chemicals
which have anti-inflammatory properties
 Because avenanthramides and phenols
reduce skin inflammation, this may explain
why oatmeal can temporarily relieve itchiness.
Companion Products
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Aveeno (cream, lotion, wash)
Dermaveen (cream, lotion, wash)
Companion Products
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Pinetarsol (contains pine tar)
 These products contains pine tar which can slow
the rapid growth of skin cells and restore the
skin's natural appearance
 Pine tar can reduce the itching and inflammation
of the skin
 Often, tar products like pine tar are used and
prescribed instead of prescription steroid creams
 Pine tar soap is designed to wash and cleanse
the affected areas while treating the eczema
inflammation
Companion Products
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Pinetarsol (bar, gel, bath oil)
Patient Counselling
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There are four areas that are important in patient counselling
of scabies:
 Identification
▪ Ensure the condition is scabies – use charts provided
 Treatment with medication
▪ Treatment requires an effective treatment and how to
apply medication appropriately in order to rid the body of
mites
 How to deal with clothing and bedding
▪ It is important to know how long the mite survives in
bedding and hot water in order to advise the patient
 Management of itch
▪ Itching persists beyond killing of the mites and because it
is intense it needs good management