SCABIES

OUTLINE

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?

Scabies is an infestation caused by the

microscopic mite (Sarcoptes scabiei)

It is found worldwide and affects people of all

races and social classes – it is NOT associated

with a lack of hygiene

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

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

She lays her eggs into the tunnel that is formed

Faecal matter from the mite is also left in these

tunnels

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

Lifecycle of the scabies mite

Organisms multiply to dozens in 2-3 weeks

Female mites live for about two months, laying

three eggs a day and travel up to three

centimetres a minute

Mites live in skin and are not shed easily

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

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

burrow

Magnified burrow Normal hand – no magnification

Symptoms of scabies

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

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

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

Scabies treatment

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

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

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

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

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

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

Because of the potential for skin irritation,

benzyl benzoate should always be patch tested

on the skin to see if any irritation develops

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

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

Itching with scabies

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

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

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 anti-

scabies treatment

Companion Products

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

Moisturisers include:

Sorbolene and glycerine cream

Emulsifiable oil baths (Alpha Keri, QV)

Emusifiable oil baths containing oatmeal

(Dermaveen, Aveeno)

Anti-itch general products

Pinetarsol

Companion products

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

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

Aveeno (cream, lotion, wash)

Dermaveen (cream, lotion, wash)

Companion Products

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

Pinetarsol (bar, gel, bath oil)

Patient Counselling

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