Lice & Scabies Flashcards
Pediculosis = ?
Lice
Describe Pediculosis (lice)
- ectoparasites that live on human hosts
- feed off of blood
- live in hair (prefer clean hair)
- do not burrow into skin
Read Pg 876 of CTMA 2 for lice pathophysiology
ok
pediculus humanus capitus
head lice
pedicures humanus corporis
body lice
phthirus pubis
pubic lice
Describe head lice
- feed every 3-6 hours so eat about 3-4 times per day
- live on hair close to scalp
- need the heat from the scalp to maintain their body temperature
- about 10-20 live lice per active infection
- they are about the size of a sesame seed
- they lay eggs called Nits
Describe body lice
- body lice will live and hide in the seams of clothes
- feed at night - which will cause nocturnal itching
- body lice are bigger than head lice
- body lice can spread disease
Describe pubic lice
- can have pinchers, thats why they are called “crabs”
- smaller pin sized head
- they are shorter
- arms are wider (need a longer reach because pubic hair is farther apart than normal hair)
- small yellow, or light brownish when empty
- brown/red when fed
- public lice can also be found in armpits, eyelids, and beards
Risk factors for Lice
- school aged children
- more prevalent in females (they have longer hair, share clothes/hats, and combs)
Is personal hygiene or socioeconomic status determine whether or not you or your kid will have lice?
not head lice
but can be a factor for body lice
T or F: lice spread disease
head lice - false
body lice - true
Describe the life cycle of lice
- adult female life cycle = 30 days and she lays about 7-10 eggs per day
- lice lays eggs (called a nit)
- eggs hatch 8-10 days later and undergo 3 nymph stages to eventually mature into adult forms within 8-15 days (head and body) or 14-22 days (pubic)
How long can head lice survive off the human for?
4 days
How long can body lice survive off the human for?
3 days
How long can pubic lice survive off the human for?
3 days
Risk factors for head lice
- aged 3-11
- female
- clean hair/healthy host
Risk factors for body lice
- poverty
- overcrowding
- low hygiene
Risk factors for pubic lice
- sexually active
- young adults
Transmission of head lice
- head to head contact
- Fomites: hats, hair accessories, brushes, towels
Transmission of body lice
- direct body contact with infested person
- shared clothing & linens
Transmission of pubic lice
- mainly sexual or close body contact
- possibly fomites (why the f u wearing hats on ur junk ?)
How fast can lice run?
23cm/min
speedy
Signs and symptoms of head lice
- pruritus (itching) especially the back and side of scalp
- this occurs when the individual becomes sensitized to the saliva from the louse feeding (this can take 4-6 weeks for initial infestation or 1-2 days for secondary infestation)
-some people may be asymptomatic
Describe eggs & nits
- nits are 0.3-0.8 mm in diameter (that’s why lice comb should have fine teeth - 0.2 to 0.3 mm apart)
- viable nits generally blend in with hair colour & and located within 6 mm of the scalp
Gold standard for diagnosing head lice?
visualization of a live louse
Signs & symptoms of body lice
- nocturnal pruritus
- bite marks around the waist and axillae
- potential secondary bacterial infection
Signs & symptoms of pubic lice
- pruritus
- bite marks
- risk of secondary bacterial infection
Describe the wet combing technique
- best way to detect lice infestation
- wash hair then apply and leave in conditioner
- brush hair
- it may help to separate the hair into sections with clips
- comb through hair with lice comb starting with comb touching the skin of the scalp and comb to the edge of the hair
- look carefully at the teeth of the comb in good light
- wipe the teeth with piece of paper towel
- do this until the whole head has been combed through
Differential diagnosis for head lice: Need to consider what other possible conditions?
- dandruff
- seborrheic dermatitis
- accumulation of hair cosmetics, paint flecks, or debris
- pseudo-nits
- psychogenic itch
Differential diagnosis for pubic lice: Need to consider what other possible conditions?
- seborrheic dermatitis
- folliculitis
- dermatophytosis (jock itch)
Differential diagnosis for body lice: Need to consider what other possible conditions?
- seborrheic dermatitis
- folliculitis
- eczema (atopic dermatitis)
- impetigo (bacterial infection)
- flea or insect bites
*also need to determine whether its body lice or bed bugs
Scabies:
describe it
-highly contagious infestation of the skin with the human mite
Scabies:
who is at risk
children, mothers of young children, sexually active adults, & elderly in nursing homes
so 91.6543% of the earth’s population
Contrast lice from scabies
lice - ectoparasite - lives outside the body
scabies - burrow into the top layer of the skin
Scabies:
Where do epidemics occur?
in poor living conditions (poverty, poor hygiene, overcrowding) & institutions
Scabies:
Required reading - describe the pathophysiology (Pg 881 CTMA 2)
- transmitted through close personal contact, particularly sexual contact
- spread by coming into contact with infested furniture, towels
- an impregnanted mite - has a rounded body and 4 pairs of legs, and HAS THE AUDACITY to burrow into the upper most layer (stratum corneum) of the epidermis
- she leaves a trail of shit as she does this - I shit you not
- then this psycho lays 2-3 eggs every day.
- she stays in the burrow (so lazy) and lays eggs til she dies (about 4-6 weeks later)
- 3-4 days after the eggs are laid, they hatch and the large w 6 legs travel from the burrow to the skin surface to mature into adult mites within 14-17 days
- then her little eggs grow up to be just as gross as their mother
On warm skin - mites can crawl how fast?
2.5 cm/min
fast little buggers
Pts typically harbour how many mites?
10-12 mites
How long can scabies survive off of the human host for?
2-36 hours at room temp
*in a cool humid environment survival is increased to about 19 days
Upon initial infection of scabies, how long does it take for sensation of the mites, eggs or feces to cause intense pruritus?
3-4 weeks
Upon secondary infection of scabies, how long does it take for sensation of the mites, eggs or feces to cause intense pruritus?
24-48 hours
Transmission of scabies
- primarily by skin-skin contact
- transmission by fomites (furniture, towels, etc) is extremely rare unless Pt has a very high parasite load
Scabies:
signs & symptoms
- redness of skin
- linear burrow with visible tracts
- itchiness (more intense at night or in warm conditions)
Scabies:
Why may you still experience itch after the parasite has left your body?
Because these gross fuckers literally leave their shit in your skin. That’s why.
You’re a fucking port-a-potty for mite shit, no wonder you’re fucking itching.
Scabies:
As a pharmacist can you diagnose scabies?
nope - must refer to physician for actual diagnosis
Scabies:
Differential diagnosis for scabies must look at other potential conditions such as?
- seborrheic dermatitis
- impetigo
- body lice
- bed bugs/insect bites
- eczema (atopic dermatitis)
Contrast atopic dermatitis and scabies.
Atopic dermatitis:
the itch that rashes
Scabies:
the rash that itches
Out of all the types of lice and scabies - which are self-treatable?
Self-treatable:
- head lice
- body lice
Not Self-treatable (need referral):
- pubic lice
- scabies
Why do you need to refer public lice and scabies?
1 - scabies is a very difficult differential diagnosis
Scabies:
red flags/ when do you refer?
- presence of secondary bacterial infection in lice or scabies infested areas (signs of infection include inflammation, pus, warm to touch)
- resistant/recurrent cases
- Pts with suspected scabies
- Pts with pubic lice
- Lice infestation in eyebrows and eyelashes
Non-pharmacological treatment & prevention for lice
- nit removal - wet combing technique
- avoid sharing personal items
- items should be dry clean, washed in hot water, or stored in plastic bag for 10-14 days
- soak combs and brushes in hot water for 5-10 mins or wash with pediculicide
- carpets, rugs and furniture should be vacuumed
*ensure family members and bedmates be treated prophylactically
Lice & Scabies:
Goals of therapy
- exterminate scabies or lice
- relieve pruritus
- prevent secondary bacterial infection
- prevent spread of the infestation
Treatment of Lice & Scabies:
Permethrin 1% & 5%:
brand name?
Nix (creme rinse, cream)
or
Kwellada P (creme rinse, lotion)
Treatment of Lice & Scabies:
Permethrin 1% & 5%:
mechanism of action?
insecticide, respiratory paralysis
Treatment of Lice & Scabies:
Permethrin 1% & 5%:
Indication?
head lice & scabies (pubic lice off-label)
Treatment of Lice & Scabies:
Permethrin 1% & 5%:
NAPRA Schedule ?
2
Treatment of Lice & Scabies:
Pyrethrin with Piperonyl but oxide (PPB):
brand name?
R&C (0.33/3%)
or
Pronto (0.33/4%)
Treatment of Lice & Scabies:
Pyrethrin with Piperonyl but oxide (PPB):
mechanism of action?
insecticide, respiratory paralysis
Treatment of Lice & Scabies:
Pyrethrin with Piperonyl but oxide (PPB):
indication?
Head & pubic lice (scabies - off label)
Treatment of Lice & Scabies:
Pyrethrin with Piperonyl but oxide (PPB):
NAPRA Schedule ?
2
Treatment of Lice & Scabies:
Isopropyl myristate 50%:
brand name?
Resultz (liquid)
Treatment of Lice & Scabies:
Isopropyl myristate 50%:
mechanism of action?
noninsecticidal, dehydration (dissolves the exoskeleton)
Treatment of Lice & Scabies:
Isopropyl myristate 50%:
indication?
head lice
Treatment of Lice & Scabies:
Isopropyl myristate 50%:
NAPRA Schedule ?
3
Treatment of Lice & Scabies:
Dimeticone 100 cSt 50%:
brand name?
NYDA (spray)
Treatment of Lice & Scabies:
Dimeticone 100 cSt 50%:
mechanism of action?
non-insecticidal, suffocation (perhaps gut rupture)
Treatment of Lice & Scabies:
Dimeticone 100 cSt 50%:
indication?
head lice
Treatment of Lice & Scabies:
Dimeticone 100 cSt 50%:
NAPRA Schedule ?
3
permethrin 1% used for?
lice
permethrin 5% used for?
scabies
pediculicide activity
ability to kill lice
ovicidal activity
ability to kill viable eggs
residual activity
retention of pediculicide on the hair and scalp after washing
Which out of the 4 products (permethrin, PPB, isopropyl myristate, and dimeticone) have pediculicide activity?
all of them
Which out of the 4 products (permethrin, PPB, isopropyl myristate, and dimeticone) have ovoidal activity?
permethrin: 70-80%
PPB: 70-80%
Isopropyl myristate: no
dimeticone: yes
Which out of the 4 products (permethrin, PPB, isopropyl myristate, and dimeticone) have residual activity?
permethrin: yes?
PPB: no
Isopropyl myristate: no
dimeticone: no
Cure rate for permethrin
96-100%
Cure rate for PPB
94%
Cure rate for isopropyl myristate
57-93%
Cure rate for dimeticone
97%
Go see Table 5: Topical Therapy for Treatment of Head Lice on pg 885-886 of CTMA 2
if i must
When recommending permethrin or PPB, what allergy must you always ask the Pt about?
chrysanthemum or ragweed
if they do have allergies to either of these, do not recommend permethrin or PPB
Permethrin:
can you use in pregnancy?
yes - it is the drug of choice
Briggs - Compatible
PPB:
can you use in pregnancy?
yes - 2nd line choice
Briggs - likely compatible
Isopropyl myristate:
can you use in pregnancy?
safety unknown
Dimeticone:
can you use in pregnancy?
safety unknown
Permethrin:
can you use when lactating?
yes - DOC (drug of choice)
Briggs - Compatible
PPB:
can you use when lactating?
yes - 2nd line choice
Briggs - likely compatible
*infant risk cannot be ruled out
Isopropyl myristate:
can you use when lactating?
safety unknown
Dimeticone:
can you use when lactating?
safety unknown
Permethrin:
can it be used in children and elderly?
use in children >2
*can be used when they’re younger under MD supervision
PPB:
can it be used in children and elderly?
use in children >2
*can be used when they’re younger under MD supervision
Isopropyl myristate:
can it be used in children and elderly?
use in children >2
*CPS clinical states not to recommend to infants and children <4
Dimeticone:
can it be used in children and elderly?
use in children >2
Pediculicide Resistance:
describe the 2 mechanisms of resistance
1) knockdown resistance - aka me when I’m drinking (kdb) - sodium channel gene mutation
2) enzyme upregulation (glutathione S-transferase)
Non-Rx products used to treat lice:
Choice depends on?
- local resistance patterns
- previous treatment
- product efficacy
- safety considerations/patient characteristics: red flags, contraindications, age, allergies
- ease of administration
- cost
- Pt preference
Non-Rx products used to treat lice:
Permethrin 1%
- first line treatment in canada
- demonstrated efficacy, good safety profile
- resistance found elsewhere
Non-Rx products used to treat lice:
PPB
- good alternative to permethrin 1%, also considered a first line treatment
- resistance found elsewhere
Non-Rx products used to treat lice:
isopropyl myristate Or dimeticone
- when permethrin or PPB contraindicated
- resistance to other agents suspected
- patient preference/opinion
Permethrin:
Describe hair, quantity, application, contact, directions, and when to reapply
Hair-towel dried hair after a wash Quantity-short hair = 30 mL Quantity-long hair = 60 mL Application - shake well and saturate hair & scalp Contact - 10 mins Directions - rinse, remove nits Reapply - 7 days
PPB:
Describe hair, quantity, application, contact, directions, and when to reapply
Hair - dry
Quantity-short hair = 25 mL
Quantity-long hair = 100 mL
Application - saturate hair, massage into scalp
Contact - 10 mins
Directions - add small amounts of cool water, massage until lather forms. Rinse. Remove nits.
Reapply - 7-10 days
Isopropyl myristate:
Describe hair, quantity, application, contact, directions, and when to reapply
Hair - dry Quantity - short = 30-60 mL Quantity - medium = 60-90 mL Quantity - long = 90-120 mL Application - saturate hair, massage into scalp Contact - 10 mins Directions - rinse, remove nits. Reapply - 7 days
Dimeticone:
Describe hair, quantity, application, contact, directions, and when to reapply
Hair - dry Quantity - short = 10 mL Quantity - med = 18 mL Quantity - long - 22 mL Quantity - very long = 34 mL Application - screw pump on. Spray hair to saturate and massage into scalp. Contact - 30 mins Directions - DO NOT RINSE. Remove nits. Leave on hair to dry at least 8 hours. Wash out with normal shampoo Reapply - 8-10 days
Why do we reapply at least 7 days after?
In case you haven’t killed all the nits. We do it 7 days after to ensure that the nit will have hatched but not have gone through the 3 bolts to form adult lice so they won’t be having more gross babies and causing further infestation.
What things could cause head lice treatment failures?
- misdiagnosis
- improper application: incorrect technique, insufficient amount, second tx not give or at an inappropriate interval
- re-infestation
- resistance
What do you do when a properly applied treatment fails?
switch to a product in a different pharmacologic class
*note - permethrin and PPB are in the same pharmacologic class
List 3 other head lice treatments
1) 5% benzyl alcohol lotion (Ulesfia)
- approved for use in canada for 6 months old to 60 yrs old
- pediculicide effectiveness but not ovicidal
- 2nd treatment needed 9 days after 1st treatment
- can cause skin irritation as a side effect
2) 0.5% malathion lotion
- not available in Canada
3) Lindane
- no longer available in canada
- risk of neurotoxicity and bone marrow suppression
- WHO recently recategorized lindane as a probable carcinogen
Alternative therapies to treat lice when standard therapy fails:
Permethrin 5%
leave on hair overnight covered with plastic shower cap
Alternative therapies to treat lice when standard therapy fails:
Septra DS
apply BID for 10 days & Nix 1% applied for 10 mins on days 1 & 7-10
Alternative therapies to treat lice when standard therapy fails:
Crotamiton
applied to scalp for 24 hours or 2 nighttime applications
Alternative therapies to treat lice when standard therapy fails:
Ivermectin
dose 200 μg/kg as a single dose followed by 2nd dose in 7-10 days
*do not use in children less than 15 kg
Alternative therapies to treat lice when standard therapy fails:
Herbal treatment
lack of adequate data to show efficacy of herbal agents and also side effects possible
ex. tea tree oil, lavender oil
Alternative therapies to treat lice when standard therapy fails:
Home remedies
hair dye, mayonnaise, petroleum jelly and cetaphil
DO NOT WORK
Alternative therapies to treat lice when standard therapy fails:
bug busting
where you heat the bugs up
-low efficacy
Alternative therapies to treat lice when standard therapy fails:
head shaving
effective but unnecessary
Treatment of pubic lice
First line treatment?
*needs a referral
- pediculicides used to treat head lice are effective for pubic lice also
- use of permethrin 1% cream rinse or PPB applied to affected areas then washed off after 10 mins are first line options, with second treatment in 7-9 days
Treatment of pubic lice:
If eyelashes are infested ?
- remove nits and lice using tweezers then
- apply white petrolatum (Tears Naturale is ophthalmic grade) twice daily for 10 days
Treatment of pubic lice:
Sexual contacts within the previous ____ should be treated if infested
month
Treatment of pubic lice:
if pediculicide causes itching - how do you treat it?
treat with oral antihistamine or topical corticosteroid
Treatment of body lice
Pediculicides unnecessary (exception is if lice are adherent to body hairs)
Hygienic measures treatment of choice:
- bathing
- launder items in hot water/dry cleaning
- seal items in plastic bags for 10-14 days
- improve lining conditions
- isolated from close contacts x 24 hours
See pg 880 for Table 2 on monitoring therapy for lice
okay man
Scabies:
infested persons and their close physical contacts from the previous ____ should be treated at the same time, WHETHER OR NOT SYMPTOMS ARE PRESENT
month
Scabies:
non-pharm treatment and prevention
- wash clothing and linens in hot water with soap and then through the hot cycle of the dryer
- store unwashed clothing in plastic bags for 5-7 days
- vacuum rugs, furniture and unwashable items
- avoid body contact with others until treatment complete
Treatment of scabies:
Most effective scabicide?
permethrin 5%
*can be used for adults and children > 2
Treatment of scabies:
What is permethrin 5% available as?
Nix dermal cream
Kwellada-P lotion
Treatment of scabies:
Second line options? (2)
1) crotamiton 10%
- antiparasitic, unknown mechanism of action
- less effective than permethrin and resistance has been reported
2) topical sulfur 5-10%
- keratolytic, fungicidal, parasitical, antibacterial
- prevents respiration in insects
- limited data demonstrating efficacy
- preferred treatment in infants < 2 months
Treatment of scabies:
Describe application of permethrin 5%
1 - apply to clean, cool, dry skin
2 - massage cream into skin from neck to soles of feet
3 - if hands are washed - reapply
4 - remove after 8-14 hours by taking a shower or bath. Dress is clean clothes
5 - reapply 7 days later if necessary
Treatment of scabies:
Nix dosing
>12 = 30 g 5-12 = 15 g 2-5 = 7.5 g <2 = 4-7 g
*if obese or scalp is involved - may need more than 30 g
Go see table 4 on pg 884
ya ya ya ya ya
Go see the 7 billion cases from Drena
alright alright alright alright alright alright alright alright
