Scabies

SCABIES
By
Dr Hussein Abulfotouh
Consultant Dermatology & Venereology

History of Scabies
• Originally, Scabies was a term used by
the Roman physician Celsus to denote
any pruritic skin disease.
• In the 17th century, Giovanni Cosimo
Bonomo identified the mite as one cause
of scabies.
• Napoleon, was said to have suffered from
the “itch” his whole life (Ramos).
• The treatment Bonomo found effective
was a local therapy, SULPHUR, which
was used up until now. He also realized
that the local treatment had to be
applied for up to two or three days after
the itching subsided because unhatched
eggs could hatch and restart the cycle.
(Ramos).

We have a couple of questions to be answered:
• What is scabies?
• What is crusted (Norwegian) scabies?
• How soon after infestation do symptoms of scabies begin?
• What are the signs and symptoms of scabies infestation?
• How did I get scabies?
• How is scabies infestation diagnosed?
• How long can scabies mites live?
• Can scabies be treated?
• Who should be treated for scabies?
• How soon after treatment will I feel better?
• Did I get scabies from my pet?
• Can scabies be spread by swimming in a public pool?
• How can I remove scabies mites from my house or carpet?
• How can I remove scabies mites from my clothes?
• My spouse and I were diagnosed with scabies. After several
treatments, he/she still has symptoms while I am cured. Why?
• If I come in contact with a person who has scabies, should I treat
myself?
CDC issue, February 2018

What is scabies?
• Scabies is an infestation of the skin by the human
itch mite (Sarcoptes scabieivar. hominis). The
microscopic scabies mite burrows into the upper
layer of the skin where it lives and lays its eggs.
The most common symptoms of scabies are intense
itching and a pimple-like skin rash. The scabies mite
usually is spread by direct, prolonged, skin-to-skin
contact with a person who has scabies.
• Scabies is found worldwide and affects people of all
races and social classes. Scabies can spread
rapidly under crowded conditions where close body
and skin contact is frequent. Institutions such as
nursing homes, extended-care facilities, and prisons
are often sites of scabies outbreaks. Child care
facilities also are a common site of scabies
infestations.

Types of Scabies
• Clean Man’s Scabies: This is seen in
individuals who bathe regularly, and keep
very clean. In this case, the lesions are
minimal and hard to see. Itching tends to
be not as intense.
• Infant Scabies: This occurs in babies
and young children, and is often
misdiagnosed or mistreated. Scabies will
affect the whole body of the child, and there
will be a large amount of pustules.
•Scabies Incognito: Normally, if a strong
type of treatment, such as steroids, are
applied then the scabies are masked and
the lesions are suppressed.

Types of Scabies
• Norwegian Scabies: This is an
intense case of crusted scabies. In
this case, there can be up to hundreds
or thousands of mites within the
lesions. This occurs commonly in
immunocompromised individuals, or
people who are mentally challenged.
They are highly contagious either by
direct or indirect contact.
• Animal Scabies: Animals are
susceptible to scabies too. Domestic
pets that contract scabies are liable to
pass it on to the other members of the
household as well.

How soon after infestation do
symptoms of scabies begin?
• If a person has never had scabies
before, symptoms may take as long as
4-6 weeks to begin.
• It is important to remember that an
infested person can spread scabies
during this time, even if he/she does
not have symptoms yet.
• In a person who has had scabies
before, symptoms usually appear
much sooner (1-4 days) after exposure

Pathophysiology
• The symptoms are caused by an allergic
reaction of the host's body to mite proteins not exactly
known
• The mite proteins are also present from the gut, in mite
feces, which are deposited under the skin
• The allergic reaction is both of the
• delayed (cell-mediated) & immediate
(antibodymediated) type, & involves
IgE presumed to mediate the very rapid
symptoms on reinfection
• The allergy-type symptoms (itching)
continue for some days, and even
several weeks, after all mites are killed
• New lesions may appear for a few days
after mites are eradicated. Nodular
lesions from scabies may continue to be
symptomatic for weeks after the mites
have been killed

Life Cycle
Scabies
Infestation:
Mites burrow under skin
to feed and lay eggs
Can burrow beneath
skin in 2.5 minutes
Adult female mite
.3 - .4 mm long

How did you get scabies?
Mode of transmission:
•Scabies usually is spread by:
-direct, prolonged, skin-to-skin
contact with a person who has scabies.
Contact generally must be prolonged; a
quick handshake or hug usually will not
spread scabies.
-Scabies is spread easily to sexual
partners and household members.
Scabies in adults frequently is sexually
acquired.
-Scabies sometimes is spread
indirectly by sharing articles such
as clothing, towels, or bedding used by an
infested person; however, such indirect
spread can occur much more easily when
the infested person has crusted scabies.

- Prisons,
- Nursing homes,
- Hospitals,
- Day care facilities
Easley contracted by old people

What are the signs and symptoms of scabies
infestation?
The most common signs and symptoms of scabies are:
1- intense itching (pruritus), especially at night, and a pimple-
like (papular) itchy rash. The itching and rash each may affect
much of the body or be limited to common sites such as the
wrist, elbow, armpit, webbing between the fingers, nipple, penis,
waist, belt-line, and buttocks. The rash also can include tiny
blisters (vesicles) & scales. Scratching the rash can cause skin
sores; sometimes these sores become infected by bacteria.
2- Tiny burrows sometimes are seen on the skin; these are
caused by the female scabies mite tunneling just beneath the
surface of the skin. These burrows appear as tiny raised and
crooked (serpiginous) grayish-white or skin-colored lines on the
skin surface. Because mites are often few in number (only
10-15 mites per person), these burrows are found most often in
the webbing between the fingers, in the skin folds on the wrist,
elbow, or knee, and on the penis, breast, or shoulder blades.
•The head, face, neck, palms, and soles often are involved in infants and
very young children, but usually not adults and older children.

SCABIES RASH
• Classical sites of scabies
rash...
• Between fingers
• Wrists
• Auxiliary areas
• Female breasts
(particularly the skin of
the nipples)
• The umbilical area
• Penis and scrotum
• Buttocks
• Inside of legs
• Ankles

How is scabies infestation diagnosed?
• Diagnosis of a scabies infestation usually based
on the customary appearance and distribution
of the rash and the presence of burrows.
• Whenever possible, the diagnosis of scabies
should be confirmed by identifying the mite. This
can be done by carefully removing a mite from the end of
its burrow using the tip of a needle or by obtaining skin
scraping to examine under a microscope for mites, eggs,
or mite fecal matter.
• It is important to remember that a person can still be
infested even if mites, eggs, or fecal matter cannot
be found; typically fewer than 10-15 mites can be present
on the entire body of an infested person who is otherwise
healthy.
• However, persons with crusted scabies can be
infested with thousands of mites and should be
considered highly contagious.

How long can scabies mites live?
• On a person, scabies mites can live
for as long as 1-2 months. Off a
person, scabies mites usually do
not survive more than 48-72 hours.
Scabies mites will die if exposed to
a temperature of 50°C (122°F) for
10 minutes.

Differential diagnosis
• Symptoms of early scabies infestation
mirror other skin diseases, including
dermatitis,
• syphilis,
• various urticaria-related syndromes,
• allergic reactions, and
• other ectoparasites such as lice and fleas
Complications
• Intense scratching can cause a secondary
skin infection, such as impetigo.

Can scabies be treated?
• Yes. Products used to treat scabies are called
scabicides because they kill scabies mites; or eggs.
Scabicides to treat human scabies are available only with a
doctor’s prescription; no “over-the-counter” products have been
tested and approved for humans.
•When treating adults and older children, scabicide cream or
lotion is applied to all areas of the body from the neck down
to the feet and toes; when treating infants and young
children, the cream or lotion also is applied to the head and
neck. The medication should be left on the body for the
recommended time before it is washed off.
• Clean clothes should be worn after each application.
•In addition to the infested person, treatment also is
recommended for household members and sexual contacts.
• All persons should be treated at the same time in order to prevent
reinfestation. Retreatment may be necessary if itching continues
more than 2-4 weeks after treatment or if new burrows or rash
continue to appear.

Scabies TreatmentSCABICIDES
• Permethrin Treatment of choice
• Applied from the neck down usually before
bedtime and left on for about 8 to 14 hours, then
showered off in the morning
• One application is normally sufficient for mild
infections
• For moderate to severe cases, another dose is
applied 7–14 days later
• May cause slight irritation of the skin, but the
sensation is tolerable
• Ivermectin
• An oral medication, often used as a single dose
• Treatment of choice for crusted scabies, and often
used in combination with a topical agent
(200microgram/Kg body weight)
• Not tested on infants and not recommended for
children under six years of age
• Topical ivermectin preparations have been
found to be effective for scabies in adults, and are
attractive due to their low cost, ease of preparation,
and low toxicity
• Has also been useful for sarcoptic mange (the
veterinary analog of human scabies)
• Other ttt:
• include lindane, benzyl benzoate, crotamiton,
malathion, and sulfur preparations)
APPLICATION OF LOTION OR
CREAM

Who should be treated for scabies?
 Anyone who is diagnosed with scabies, as
well as his OR her sexual partners and other
contacts who have had prolonged skin-to-skin
contact with the infested person, should be
treated.
 Treatment is recommended for members of
the same household as the person with
scabies.
 All persons should be treated at the same
time to prevent reinfestation.
 Retreatment may be necessary if itching
continues more than 2-4 weeks after
treatment or if new burrows or rash continue
to appear.

Is it possible to get scabies from
your pet?
•No. Animals do not spread human scabies.
• Pets can become infested with a different kind
of scabies mite that does not survive or
reproduce on humans but causes “mange” in
animals.
• If an animal with “mange” has close contact with a
person, the animal mite can get under the person’s
skin and cause temporary itching and skin irritation.
• Although the person does not need to be treated, the
animal should be treated because its mites can
continue to burrow into the person’s skin and cause
symptoms until the animal has been treated
successfully.

Can scabies be spread by swimming in a
public pool?
• Scabies is spread by prolonged skin-to-skin contact
with a person who has scabies. Scabies sometimes
also can be spread by contact with items such as
clothing, bedding, or towels that have been used by a
person with scabies, but such spread is very
uncommon unless the infested person has crusted
scabies.
• Scabies is very unlikely to be spread by water in a
swimming pool. Except for a person with crusted
scabies. (Only about 10-15 scabies mites are present on an
infested person; it is extremely unlikely that any would emerge
from under wet skin).
• Although uncommon, scabies can be spread by
sharing a towel or item of clothing that has been used
by a person with scabies.

How can you remove scabies mites from
your clothes, house or carpet?
• Scabies mites do not survive more than
2-3 days away from human skin. Items
such as bedding, clothing, and towels used by a
person with scabies can be decontaminated by
machine-washing in hot water and drying using
the hot cycle or by dry-cleaning.
• Items that cannot be washed or dry-cleaned
can be decontaminated by removing from any
body contact for at least 72 hours.
• Because persons with crusted scabies are
considered very infectious, careful vacuuming
of furniture and carpets in rooms used by these
persons is recommended.

If you are diagnosed with scabies. After several
treatments, still you have symptoms while you
are cured. Why?
• The rash and itching of scabies can
persist for several weeks to a month after
treatment, even if the treatment was successful
and all the mites and eggs have been killed. Your
health care provider may prescribe additional
medication to relieve itching if it is severe.
• Symptoms that persist for longer than 2 weeks
after treatment can be due to a number of
reasons, including:

Persistence of symptoms after ttt due to:
• Incorrect diagnosis of scabies. Many drug reactions
can mimic the symptoms of scabies and cause a skin rash
and itching; the diagnosis of scabies should be confirmed
by a skin scraping that includes observing the mite, eggs,
or mite feces (scybala) under a microscope.
• If you are sleeping in the same bed with your spouse and
have not become reinfested, and you have not retreated
yourself for at least 30 days, then it is unlikely that your
spouse has scabies.
• Reinfestation with scabies from a family member
or other infested person. infested persons and
their contacts must be treated at the same time
to prevent reinfestation.

• Treatment failure caused by resistance to
medication, by faulty application of topical scabicides, or by
failure to do a second application when necessary; no new
burrows should appear 24-48 hours after effective treatment.
• Treatment failure of crusted scabies because of
poor penetration of scabicide into thick scaly skin containing
large numbers of scabies mites; repeated treatment with a
combination of both topical and oral medication may be
necessary to treat crusted scabies successfully.
• Reinfestation from items (fomites) such as
clothing, bedding, or towels that were not
appropriately washed or dry-cleaned (this is mainly of concern
for items used by persons with crusted scabies); potentially
contaminated items (fomites) should be machine washed in hot
water and dried using the hot temperature cycle, dry-cleaned, or
removed from skin contact for at least 72 hours.

• An allergic skin rash (dermatitis); or
• Exposure to household mites that cause
symptoms to persist because of cross-
reactivity between mite antigens.
• If itching continues more than 2-4 weeks or if
new burrows or rash continue to appear, seek
the advice of a physician; retreatment with the
same or a different scabicide may be
necessary.

If you come in contact with a person who has
scabies, should you treat yourself?
•No. If a person thinks he or she might have scabies, he/she
should contact a doctor. The doctor can examine the person,
confirm the diagnosis of scabies, and prescribe an appropriate
treatment.
•Sleeping with or having sex with any scabies infested
person presents a high risk for transmission. The longer a
person has skin-to-skin exposure, the greater is the likelihood
for transmission to occur. Holding the hand of a person with
scabies for 5-10 minutes could be considered to present a
relatively high risk of transmission.
•However, transmission can occur even after brief skin-to-
skin contact, such as a handshake, with a person who has
crusted scabies. In general, a person who has skin-to-skin
contact with a person who has crusted scabies would be
considered a good candidate for treatment.

When prophylactic treatment should be given to reduce
the risk of transmission?
Early consultation should be sought with a health care
provider who understands:
1- the type of scabies (i.e. non-crusted vs crusted) to
which a person has been exposed;
2- the degree and duration of skin exposure that a person
has had to the infested patient;
3- whether the exposure occurred before or after the
patient was treated for scabies; and,
4- whether the exposed person works in an environment
where he/she would be likely to expose other people during
the asymptomatic incubation period. For example, a nurse
or caretaker who works in a nursing home or hospital often
would be treated prophylactically to reduce the risk of
further scabies transmission in the facility.

Preventive measures during Scabies
outbreaks
 Mass treatment programs that use topical
permethrin or oral ivermectin
 There is NO vaccine available for scabies
 The simultaneous treatment of all close
contacts is recommended, even if they show no
symptoms of infection (asymptomatic), to
reduce rates of recurrence
Families are treated all at the same time.
 Asymptomatic infection is relatively common
 Rooms used by those with crusted scabies
require thorough cleaning
 Maintain a high level of suspicion if patients
present with undiagnosed skin rashes

THANK YOU
Every ending is just only a
new beginning

Scabies

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