Lice, scabies, spider bites Flashcards
1
Q
What is pediculosis?
A
- ectoparasites that live on body and feed on human blood after piercing the skin
- pediculosis capitus: head lice
- pediculosis corporis: body lice
- very common
- body and scalp lice are about 1-3 mm long
- unable to jump or fly
2
Q
Clinical presentation of pediculosis?
A
- pruritus: may take 2-6 wks to develop after 1st exposure
- itching and scratching can lead to secondary cellulitus
- pubic lice should prompt eval for other STIs
3
Q
Dx of pediculosis?
A
- observe:
eggs (nits)
nymphs
mature lice - commonly found behind ears and on back of neck
- wood lamp of area: yellow/green fluorescence of lice/nits
4
Q
Meds for pediculosis?
A
focus on 2 mechanisms:
- neurotoxicity - permethin 1% lotion (nix) first line
- suffocation via coating: benzyl alcohol 5% lotion (Ulesfia)
spinosad 0.9% (natroba): promotes hyperexcitiation and death by paralysis
- enviro control: tx all persons who have contact with infested pts (esp partners)
5
Q
What are scabies?
A
- sarcoptes scabiei
- aka seven yr itch
- contagious infection caused by mite Sarcoptes Scabiei
- tiny and usually not directly visible
- parasite that burrows under the host’s skin causing intense itching
6
Q
How are scabies transmitted? When does the pt become sx?
A
- may be transmitted from objects
- most often transmitted by direct skin to skin contact:
higher risk for prolong. contact
nursing homes
extended care facilities
prisons
child care facilities - usually 2-6 wks b/f pt becomes sx
7
Q
3 MC skin disorders in kids?
A
- scabies
- Tinea
- pyoderma
8
Q
Classic scenario of scabies?
A
- itching: caused by allergic rxn to mites made worse by warmth usually worse at noc watch for excoriation - see burrowing - common areas: wrists, axillae, waist, feet, ankles
9
Q
How is scabies dx?
A
- scrape off tiny bit of skin
- view under a microscope for mites or eggs
10
Q
Tx for scabies - 1st line? SEs?
A
- permethrin cream 5% 60 g tube (preferred)
- apply from head to feet
- leave on 8-14 hrs then wash with soap and water
- repeat in 7 days if necessary
- safe for kids as young as month old and pregnancy
- SEs:
mild to mod burning and stinging
itching
rash
redness - tx family members and sexual partners
- wash clothing, bedding, or towels in hot water and dried using hot temp
- can give something for itching:
atarax (hydroxyzine) 10-25 mg po q 4-6 hrs prn itching - steroid cream
- watch out for secondary infections
11
Q
Alt meds for scabies?
A
lindane lotion 1%:
- has more neurotoxicity than permethrin
- apply thin layer of lotion and massage from neck to toes: leave on 8-12 hrs
- most pts reqr 30 ml but larger adults up to 60 ml
oral ivermectin:
- one study found that is more effective than lindane but less effective than permethrin
- 200 mcg/kg by mouth as single dose with repeat dose in 2 weeks
- CDC recommends not using in pregnant or lactating women
12
Q
What spiders are most likely to inflict medically significant bites?
A
- widow
- recluse
- there are a lot of common disorders can mimic a spider bite
- acute presentation: papules, pustules, or wheal (most resolve 7-10 days)
13
Q
What disorders can mimic spider bites?
A
- other insect bites: flea, fly, mite, tick bites
- skin disorders: erythema nodosum, TENs
- infections: chronic herpes simplex, MRSA
14
Q
Where are widow spiders found?
A
- worldwide
- outside - garage, shed, under furniture
- unremarkable local lesions: characteristic systemic rxn
- latrodectus genus
- not all are black
- neurotoxin: alpha-latrotoxin = effects neuromuscular transmission
15
Q
Where are recluse spiders?
A
- found in N and S America
- notorious for becoming necrotic (rare)
- systemic rxn mild: nonspecific signs and sxs
- loxosceles genus
- brown
- sphingomyelinase D = tissue destruction and hemolysis
