Pediculosis and Scabies (3) Flashcards
What is pediculosis
lice infestation
What are the 3 types of lice that feed on humans
Pediculus capitis (head lice)
Pediculus corporis (body lice)
Phthirus pubis (pubic lice)
Head lice
Most common type of lice
Commonly picked up at schools and day care centers (increased risk with sharing of clothing, bedding, head pieces)
Can effect all socioeconomic groups
Nits (eggs) will be brown specks attached to hair
Live lice are white - note they are attached to hair, can’t easily shake off like dandruff
Body lice
Live and lay eggs in seems of clothing
Can transmit infections (typhus and trench fever)
Occur in homeless people (not showering, changing clothing)
Pubic lice
Mostly transmitted through sexual contact
Can also be through toilet seats, shared undergarments, bedding
Can also infest armpits, eyelashes, eyebrows, mustaches, and beards
aka crabs
Life cycle of lice and why this is important to consider
Egg stage (nits)
-hatch in 8-9 days
Nymph stage
-grow of 9-12 days can’t lay eggs
Adult stage
-lay eggs
This is important to think about because some agents will only kill live lice, not eggs, so we may need to retreat when those hatch
Lice goals of therapy and treatment approach
Get rid of lice by killing adult and nymph lice
Remove nits from hair (nit comb)
So first - apply pediculocide to infested body area for designated amount of time
Then - comb hair with nit comb to remove eggs and dead lice
How is pediculosis diagnosed?
by visual inspection
if they do not allow you do to do a visual inspection you cannot recommend pediculicide
What are some exclusions to self care for pediculosis
Hypersensitivity to chrysanthemums, ragweed, or other product ingredients
Presence of secondary skin infection (redness, oozing, puss - requires referral)
Eyelid or eyebrow involvement
Pregnancy/breastfeeding
Presence of active tumors
There are certain age restrictions for products
What are the 2 OTC products used for lice
Pyrethrins + piperonyl butoxide = RID
-piperonyl butoxide is added to enhance pyrethrin concentration
Permethrin 1% = NIX
What is RID vs NIX approved for
RID = head and pubic lice
NIX = head lice only
RID administration/use
RID (pyrethrin) works by coming into contact with lice, blocking nerve transmission and therefore causing paralysis and death
So, contact time is important…
-apply to affected area for 10 minutes - then rinse and shampoo
-avoid eyes and mucus membranes
Then comb with nit comb
Since it does NOT kill eggs (only live lice), must be used again in 7-10 days to kill any nits that may have hatched
DO NOT apply more than twice in 24 hours (excessive contact time can increase absorption and lead to toxicity)
RID ADRs
Irritation, erythema, itching, swelling
RID should NOT be used in which patients? (2)
Those with chrysanthemum allergy
(caution with ragweed allergy)
And children under 2 years of age
NIX administration/use
Apply to affected area for 10 minutes then rinse
-for head lice only
Then comb with nit comb
Retreatment is NOT required (unless active lice are detected)
-NIX does not kill eggs, but it has a lingering effect for up to 10 days - so that when eggs hatch they will be killed
NIX adrs
Irritation, burning, itching, stinging
-minimal skin absorption
NIX should not be used in which patients? (2)
Those with allergy to chrysanthemums or pyrethrin
Infants under 2 months
What is the drug of choice for headlice?
Spinosad 0.9% topical suspension
(this is the drug of choice for head lice)
BUT it is RX only
Spinosad place in therapy
only approved for HEAD lice
This is the drug of choice - but is limited by prescription only availability
can be effective for resistant lice that are not responsive to pyrethrin or permethrin
can be used in patients sensitive to chrysanthemums or pyrethrins
Spinosad administration/use
Apply to dry scalp first, then apply to dry hair
Leave on for 10 minutes then rinse
Kills BOTH eggs and lice
-nit combing not required
-retreatment not required (unless active lice after 7 days of treatment)
Spinosad can NOT be used in which patients?
Under 6 months old
Which OTC lice therapy is superior after only ONE application
NIX … because it does not need to be applied again due to lingering effect for 10 days
But, in the case that it does need to be used twice - then RID and NIX are equally effective
Scabies background/pathophysiology
“itch mite”
Parasites
Infection persists until they are removed (can live long on person, but only 48-72 hours off a host)
They get underneath the stratum corneum and deposit eggs - common in skin folds, under arms, in between fingers, buttocks, axillary folds, external male genitalia
But can also form in random spots
How are scabies spread?
By direct, prolonged (20 minutes at least) skin to skin contact
-adult scabies is often sexually acquired
Can be spread indirectly through shared clothing, towels, or bedding - but not as common
Common in child care facilities
Nursing homes / long term care facilities
Prisons
Scabies from dogs
Dogs CAN spread scabies - but these are different than human scabies
-the species that infects dogs, will NOT reproduce on humans
(specific scabies will only live in the specific species of host they are attracted to)
And dogs can NOT spread human scabies
So you can get scabies from a dog but it is self limiting
Onset to symptom presentation with scabies
In scabies naive patients… may take 4-6 weeks to begin
In patients who have had scabies before… faster onset (typically 1-4 days after re-exposure) - makes sense - quicker reaction since they have been exposed to that irritant before
Scabies symptom presentation
inflammation
intense itching
pimple like rash
Can scabies be treated with OTC products?
NO - scabies is not a self care condition
need to see a provider for prescription therapy
What 3 agents can be used for scabies treatment?
Permethrin 5% (note 1% was used for lice OTC)
Crotamiton - frequent treatment failure reported, adults only
Ivermectin - one time oral dose, for those who cannot tolerate permethrins
Permethrin 5% for scabies administration/counseling
Cream should be applied from the neck down to soles of feet
Leave on for 8-14 hours then wash off
All family members should be treated
Symptoms may persist for up to 2 weeks post treatment
Retreat after 1 week - because it is unclear if eggs are killed or not
Permethrin 5% can NOT be used in which patients?
Infants under 2 months
