Block 1- skin infestations Flashcards
scabies Etiology
microscopic mites (Sarcoptes scabiei)
scabies Epidemiology
skin-to-skin, fomites, communal living
usual location of scabies on human body
Location - finger webs, flexor surfaces, groin
SYMPTOMS OF SCABIES
intense pruritus
What to expect on physical exam of scabies
scratch marks, burrows, vesicles, pustules, crusts
how to make diagnosis of scabies? (test)
mineral oil prep (or KOH)
in scabies, when is itching most severe?
at night
scabies treatment
- PERMETHRIN 5% (Elemite) cream
o from the neck to the toes (avoid face and scalp) for 8 hrs then rinse;
o repeat Rx in one week: whole household every time
o Launder and vacuum ALL fomites (towels, bedding, carpet, sofa) - Oral ivermectin is very safe and extremely effective, in 1 single dose
Excellent option for nursing home outbreaks
is Crusted scabies (Norwegian scabies)
common in US?
NO very rare
presentation of a person infected with Crusted scabies (Norwegian scabies)
marked thickening and crusting of the skin, Can involve face
describe what lesions look like for Crusted scabies (Norwegian scabies)
Lesions are often hyperkeratotic, crusted, and cover large areas
what kind of patients tend to get infected with Crusted scabies (Norwegian scabies)?
- Immunocompromised patients only: HIV, Lymphoma, neglected or homeless
name the insect:
- Common tiny red arachnid
- Barely naked-eye visible
- eight legs
- Forests and vegetated areas, humid climates
chiggers
do chiggers burrow into and remain inside the skin?
no- common myth
process of chiggers infecting human and then releasing from host
- Chiggers attach to the skin and inject enzymes that cause destruction of host tissue.
- Hardening of the surrounding skin results in the formation of a feeding tube called a stylostome
- Chigger s then feed upon the destroyed tissue for 2-4 days then drop off…
- Days after they release, the host is left with persistent red itchy bumps!
treatment of chiggers
- Nail polish: Does not kill chigger, but reduces itchiness -seals the area off from the air, which reduces itch, also keeps fingernails off the bump!
- Tx the Pruritis:
o Ultrapotent topical class I or II topical steroid creams
o Antihistamines of limited value, mostly if patient has trouble sleeping
o Systemic steroids for severe cases
o Nail polish or cyanoacrylate (super glue)
3 forms of lice:
- Pediculus humanus capitis (head louse) [age 2-11]
- Pediculus humanus corporis ( body louse) [homeless]
- Phthirus pubis (“crabs”, pubic louse) [sexually transmitted]
head lice is most commonly found in ___?
school aged white children
body lice is most commonly found in ___>
homeless or disabled/neglected pts
pubic lice is most commonly found in
promiscuous individuals/ prostitutes
lice Feed on human blood after piercing the skin and injecting saliva, this causes what kind of lesion?
pruritus
- Lice die of starvation within __ days off host, eggs die within __ days off host
3
14
lice treatment
- Over the Counter medication
o Pyrethrin shampoos /rinses and spray for surfaces: ineffective due to widespread resistance
o Various dry-on-the scalp remedies (cetaphil, mayonnaise, etc.) to suffocate lice
o Nit-picking services: expensive but effective - Rx medication
o Permethrin : ineffective due to widespread resistance
o Lindane (Kwell): NEVER use this. It can cause seizures
o Spinosad (Natroba)
Very low toxicity
Very high efficacy
Over $100 if no insurance
Only takes 10 minutes, and no need to comb out nits!
o Topical ivermectin (Sklice)
Also single-dose of 10 minutes, and no nit-combing
what medicine should you never use to treat lice?
lindane
- P. pubis infestations of the eyelashes are treated with occlusive therapies such as?
o Petrolatum (twice daily for 7-10 days) - asphyxiant for eyelash infestation
treatment of body lice
- launder in hot water
- iron with a hot iron
- dry in a hot dryer
no medications necessary
- Primary lesion is for insect bite
variably excoriated papular urticaria
what kind of secondary infection could you get from insect bites if you scratch?
staph/strep (impetigo) from scratching
for insect bites, can bite reactions be delayed?
yes
treatment of insect bites
class I or II topical steroid to closed lesions; consider oral antihistamines if severe
characteristics of black widow bites
painful mild local reaction, hours later cramps due to neurotoxin
characteristics of brown recluse bites
mild to severe acute reaction, days later: necrosis
name disease:
serpiginous eruption caused by burrowing larvae of the dog hookworm (Ancylostoma sp.)
Cutaneous Larva Migrans:
Cutaneous Larva Migrans is commonly found where?
tropical countries
Cutaneous Larva Migrans treatment
anthelmintic drugs such as albendazole
Seabather’s Eruption is caused by?
jellyfish larvae
usual site of Seabather’s Eruption
under clothing
Seabather’s Eruption treatment
remove clothing before rinsing with cool water or more stings will occur
- Supportive care with topical corticosteroids and antihistamines as needed
jellyfish sting (envenomation) Immediate therapy:
Neutralize stings via irrigation with vinegar:
- soak or rinse the area in vinegar (acetic acid) for 15-30 minutes to stop the nematocysts from releasing their toxins.
Alternatives: rinse in sea water, 70% isopropyl alcohol
can you use fresh water to treat jellyfish sting?
no
- Fresh water will cause the nematocysts to continue to release their toxin.
after neutralizing jelly fish sting with vinegar, what should you do?
- Shave the area with a Razor or Credit card: apply shaving cream or baking soda powder paste
- Shave next-Removes any adherent nematocysts
- Then reapply vinegar or alcohol
The shaving cream or paste prevents nematocysts that have not been activated from releasing their toxin during removal with the razor
if jellyfish sting in eye, how to treat it?
rinse with normal saline
if symptoms persist in the following days of a jellyfish sting, what should you treat with?
- In the following days, treat with topical corticosteroids if symptoms persist.
can Box jelly fish sting be fatal?
yes
bed bug Bites are typically painless, but the subsequent allergic reaction can cause intense _____.
pruritus
presentation of bed bug bites
- erythema, wheals, vesicles, or hemorrhagic nodules
common places to get infected by bed bugs
- Mattresses, suitcases
how to treat bed bugs
- Hyperthermia (whole house heating) or insecticides to kill bugs
