LICE

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LICE IDENTIFICATON TREATMENT
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• Pediculosis Capitis
  - head lice infection or infestation
• Pediculosis Corporis
  - body lice
  - usually
  associated with poor socio-economic conditions
  i.e. homeless infrequent change of
  clothing/poor hygiene

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Transmission

• Usually head-to-head contact
• Can be contracted through the sharing of brushes,
  hats, scarves, coats, bedding/linens, etc.

• Obligate human parasite (a parasite organism that
  cannot complete its life cycle without dependence
  on its host) cannot be transferred through
  pets/animals

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Life Cycle

• Mature female can
  lay 3 6 eggs/day
  and live for
  about 1 month
• Eggs hatch within 6 10 days, maturity reached
  after another 10 days
• nits may survive up to 3 weeks after removal
  from the host

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MALE

• FEMALE

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Facts

• Most commonly affects children
  3 11 years of age but anyone
  can be affected
• Common to have outbreaks
  at schools, dormitories, etc
• Prevalence - Female gt Male
• Likely many unreported due to stigma attached to
  infection
• Lice prefer a clean environment

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• Approx. 1 3 mm long
• Flat
• Wingless
• 3 sets of legs - insect

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Signs Symptoms

• Most often found on the warmer areas of the head
  behind the ears back of head neck
• Itching common, especially at night
• Excessive scratching can cause inflammation and
  secondary bacterial infection
• Lice lay eggs or nits, cemented, close to the
  base of the hair shaft
• Eyelashes (rarely) may be involved as well

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IDENTIFICATION

• Live lice may be detected, but they move very
  quickly, and shy away from light so detection of
  live lice may be difficult advantageous to use
  2 people to check the infected person
• - many of those infected will have lt 10
  organisms present
• Lice appear
  sluggish away
  
  from the warm
  
  scalp
• Usually 24 hour
  survival off the host
• Some recent data suggest
  for up to 55 hours

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IDENTIFICATION OF NITS

• Important to distinguish nits from other
  possibilities
• Dandruff, residues from gels/lacquers can look
  like nits
• Recent, viable un-hatched eggs are
  creamy-yellow and very close to the scalp while
  older nit shells are further away from the
  scalp and white in colour
• Oval in shape, slightly smaller than a sesame
  seed, never irregular in shape, fuzzy, or
  encircle the hair

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TREATMENT

• A NIT REMOVAL COMB IS AN EFFECTIVE
  SCREENING TOOL

• Manual removal may be the most important step,
  and it is possible to treat head lice with this
  method alone

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TREATMENT

• Mainstay of treatment insecticides

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• Lice and other arthropods are killed by these
  medications blocking nerve impulses causing
  paralysis and death of the parasite

• Products should be applied to clean, dry hair in
  sufficient quantity to saturate the hair/scalp
  (especially behind the ears and the nape of the
  neck) and left on for 10 minutes, then rinsed.
• Other treatments, petroleum jelly, kerosene,
  Tea-tree oil and others are either ineffective or
  unsafe

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• Nit or egg removal should follow with a
  fine-toothed nit comb.
• Soaking the hair and wrapping the scalp with a
  50/50 solution of vinegar and water for at least
  15 minutes
• Machine wash (hot) and dry all hats, scarves,
  coats, bedding, if possible, and dry in dryer on
  the hot setting
• For articles that cannot be
  cleaned this way, dry clean
  or seal up in a plastic bag
  for one
  week

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• The nit comb, as well as other combs, brushes,
  barrettes, etc can be soaked in rubbing alcohol
  for 1 hour

• Clean house room by room by thorough vacuuming
  (rugs, furniture, floors)
• All close contacts should be thoroughly screened
  and treated only if necessary

• After treatment, person should be checked
  regularly for any evidence of lice or nits
• Re-treatment may be necessary and alternate
  agents may have to be used - resistance

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• Itching, redness, and inflammation may persist
  for several days after successful treatment and
  may not necessarily mean re-application is
  required

• Even the presence of live organisms several hours
  after treatment does not indicate that the
  treatment was unsuccessful often these parasites
  take several hours to die after exposure to
  treatment

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ALTERNATE TREATMENT

• Electric battery-powered comb zaps lice
• Some success
• Price - 50

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REFERENCES

• Centers for Disease Control and Prevention.
  Parasitic disease information head lice
  infestation. Division of Parasitic Diseases.
  http//www.cdc.gov.
• Hansen RC, et al. Guidelines for the treatment of
  resistant pediculosis. Contemporary Pediatrics
  2000 AugS1-10.
• Hipolito RB, Mallorca FG, Zunia-Macaraig ZO, et
  al. Head lice infestation single drug versus
  combination therapy with one percent permethrin
  and trimethoprim/sulfamethoxazole. Pediatrics
  2001107(3)p.e30.
• Burson, SC, Permethrin-Resistant Head Lice
  Pharmacist's Letter 199915(11)151116
• Clinical Pharmacology http//cpip.gsm.com