Scabies

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Scabies

• Suzanne Averill
• Health Protection Nurse

HPA West Midlands East Bartholomew House 142
Hagley Road Edgbaston Birmingham B16 9PA
2

• Scabies infection is manifested by an itchy rash
  (usually)
• Caused by a tiny mite burrowing under the skin
  where the female mite lives, breeds and dies

3

• The scabies mite
• Feeds
• Defecates
• Lays eggs
• Dies
• All in the burrow
• Each one releases antigens that diffuse into the
  epidermis

4

• Sarcoptes scabiei
• Broad oval shape
• 300-500?m long by 230-420 ?m wide
• Parasitic
• Live, breed and die on humans
• Adult females live in burrows in the epidermis
• Adult males and immature mites wander on skin

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• Life cycle
• Eggs hatch 50-53 hours
• Larval stage 77-101 hours
• Protonymph stage 56-80 hours
• Tritonymphal stage 53-77 hours
• Lives from 4 6 weeks and adult female lays 2
  4 eggs a day

6

• Most scabies lesions are due to delayed
  hypersensitivity
• Only atopics show true allergic reactions, with
  skin and circulating IgE

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No one but Kings and Princes should have the
itch for the sensation of scratching is so
delightful James I of England

• The history of the discovery of the agent of
  scabies and of the disease itself is fascinating
  and controversial. Ramos-e-Silva 1998
• Been around a long time!
• Aristotle (384 322BC)
• Napolean I seems to have suffered from it all his
  life
• Study done in 1687 1st described the parasitic
  theory of infectious diseases

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• Studies in Prague, Sheffield, and India in the
  1960s and 70s found
• Each index case led to approx 2.6 cases
• Mostly intra-family transmission
• Inter-family transmission mainly by teenagers
• Treatment generally straightforward
• Whole body from the neck down
• Only one application required

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• Denmark
• Notifiable from 1881 to mid-1980s
• Various increases and reductions on a roughly 20
  year cycle
• Both sets of data showed
• Teens gt6 times as likely and primary school
  children gt4 times as likely to catch scabies
• Over 60s extremely low risk

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What is happening now?

• Since the late 1980s scabies has increased
  exponentially, especially in the over 60s, in
  all western countries
• People in care
• Are most difficult to diagnose
• Often develop crusted scabies
• Are often difficult to treat, leading to
• Complex management problems
• Disruption, staff unrest, bad publicity

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Scabies Infection

• Transmission relies on a mite being passed from
  one person to another
• Skin to skin contact
• How long is prolonged?

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Burrows

• Mites appear to prefer non-hairy skin and areas
  of low sebum production

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Signs and Symptoms

• Itchy generalised rash can be bilateral and
  symmetrical
• Pruritus affecting all parts of the body except
  head and middle of the back
• Itching is more intense at night
• Lesions near to the burrows

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The Rash

• Allergic reaction to the mite being present
• Type IV delayed hypersensitivity to saliva and
  faeces of mite
• Rash is widespread and very itchy
• In Crusted scabies the hosts response to the
  mite is modified allowing them to multiply
  unheeded

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Diagnosis

• The great imitator
• Clinical history
• Dermatoscope
• Skin scrapings
• Eggs
• Faeces
• Mites

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Diagnosis

• Look for
• Burrows
• Spots
• Pustules
• History of itching worse at night or when hot
• Evidence of communicablility

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Diagnosis

• Skin scrapings
• Use scalpel blade
• Scrape suspicious areas
• Put onto slide
• Inspect under microscope

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Clinical manifestations

• Classical scabies
• Average number 11 mites
• Norwegian/ hyperkeratotic/
• Crusted scabies
• Average number of mites 1,000s!!

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Norwegian/Crusted Scabies

• Highly infectious
• Potential contamination of the environment
• Responsible for outbreaks in institutions

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Demonstrating the little brutes

• Various ways have been tried in attempts to
  extract mites
• Shave biopsy
• Sellotape stripping
• Super glue stripping
• Skin scraping
• Needle extraction

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If only life were simple!

• It would be just a matter of picking out mites
  from the burrows using a needle

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Treatment

• Ivermectin
• Insecticde (malathion, permethrin)
• Aqueous based Lyclear dermal cream, Malathion
• Apply treatment all over the body and ?head
• Cut and clean under fingernails and apply
  treatment
• Leave for recommended time
• Reapply if washed off
• Reapply second application 7-10 days later
• Rash and itch may continue for a while

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Treatment of Scabies Outbreak in a Nursing Home
Resident Staff Member
Affected
Yes
No
Yes Affected
No
Unaffected family members
Staff Family Unaffected member
family member
Staff
D1
Permethrin Permethrin
Permethrin Permethrin Permethrin
Permethrin
No treatment
D7
Permethrin No Treatment,
monitor over the next 7 days
Permethrin Permethrin No Treatment No
Treatment but monitor
Monitor retreat if necessary using a topical
Ivermectin
D14
Monitor retreat if necessary
If signs symptoms are evident begin treatment
N.B. The itch of scabies continues for 2-3 weeks
following treatment. Relieve the itch with Eurax
or calamine. In severe cases of crusting using an
emollient to help remove crusts will enable
treatment to work more effectively.
A 2nd Ivermectin dose topical may be needed in
cases of severe crusted scabies
D21
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Management

• Reassure and provide information
• Identify close contacts
• Household
• Sexual partners
• Those who have close skin to skin contact i.e
  carers
• Order adequate amounts of lotion
• Set a date for everyone to treat themselves

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What are the keys to success in managing
outbreaks?

• Accurate and rapid diagnosis of ve cases
• Effective risk assessment for contacts
• Thorough and comprehensive strategy for managing
  outbreaks
• Efficient execution of policy
• Enough treatment for the job
• Enough staff to do the work
• Good PR management facts and information
• Staff
• Families of staff and residents
• Media (if required)

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Outbreak control

• Confirm diagnosis
• Identify all close contacts (pebble in the pool
  approach)
• Get enough treatment
• Apply treatment on same day
• Ensure treatment stays on skin for full
  recommended period
• Repeat 7 days later
• Monitor

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Policies

• Risk assessments needed
• High risk
• Staff with intimate resident contact
• Staff moving between wings or wards
• Physios, OTs, chiropodists, etc.
• Relatives of scabies patients
• Medium risk
• Ministers of religion, GPs, transport staff
• Staff relatives
• Low risk
• Cooks, gardeners, etc
• Other relatives

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Policies

• Monitoring of new residents and day care
• Evaluate risk at different levels
• Residents
• Staff
• Staff families
• Visitors
• Work out strategy for outbreaks with HPU team
• Determine treatment approach who is included?

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References

• Millership S, Readman R, Bracebridge S (2002)
  Use of Ivermectin, given orally, to control
  scabies in homes for the elderly mentally ill.
  Communicable Disease and Public Health Vol 5 No 2
  June 144 146
• Hawker J, Begg N, Blair I, Reintjes R, Weinberg J
  (2005) Communicabel disease control handbook
  (second edition) Blackwell Publishing Ltd.
  Oxford.
• Christopherson J (1978) The epidemiology of
  scabies in Denmark 1900 1975. Archives of
  Dermatology Vol 114 May 747 750
• Burgess I (1996) Management and guidelines for
  lice and scabies Prescriber 5 May 87 - 104