Infestations - Exam 1 Flashcards
How is Imiquimod 5% dosed? What is the max number of weeks? MC SE?
Apply small amount at bedtime 3x/wk - rub cream in until no longer visible
Cont Tx until complete clearance - maximum of 16 wks
Localized inflammatory reaction (redness, irritation, induration, ulceration, erosions, and vesicles) May need several day holiday if SE are too severe
What is the etiology behind verruca?
HPV
What is shingles caused by? What are the 3 phases? New lesions can appear for up to ____ weeks. What is the testing of choice?
Reactivation of Varicella Virus
- Prodrome
- Active Infection
- Post Herpetic Neuralgia
1 week
PCR
What am I? Where do outbreaks commonly occur?
Pediculosis Capitis
schools and day-care centers
Describe the physical characteristics of a louse. How long is the lifespan?
1-3 mm long, flattened brownish-gray, with 3 pairs of legs and claws
lifespan 14-18 days
pediculosis capitis/pubis are found on the _______. pediculosis humanus is found on the _______
capitus/pubis - located on hair shaft
humanus - found in seams of clothing/bedding
Who is the MC pt with Pediculosis Capitis? What time of the year?
female white school aged children/mother
warmer months
How can you tell the difference between the scales of seborrheic dermatitis and pediculosis capitis?
seborrheic dermatitis scales are greasy, yellow and irregular shaped and easily removable
pediculosis capitis are hard to remove and adhere to the hair shaft
How long do lice live on the host? How long can they live off the host? When do nits hatch?
Lice live approximately 30 days on the host and <1 day off the host only a few hours
Eggs (nits) hatch within 7-10 days
Beside nits or live lice on the scalp, how else can you determine if there is an infestation of pediculosis capitis?
Maculae ceruleae or purpuric stains on the skin of the occipital scalp and nape of neck may signal an infestation
Occipital lymph nodes
_____ is an infection with bacteria causing pus under the skin in the scalp along with occipital and cervical lymphadenopathy suggest possible ______
pyodermas
pediculosis infestation
What will nits look like under a Wood’s lamp?
Nits fluoresce and are readily detected with a Wood’s lamp and do NOT move freely
What is the best test for determining a Pediculosis Capitis infestation?
Demonstration of lice or nits on hair visually or under microscope
Wood’s lamp demonstrates fluorescent nits
What are the pt precautions with an pediculosis capitis infestation?
Isolate patient, wear gloves and a gown, limit patient transport, and avoid sharing patient-care equipment
When should you tx a child with rx strength lice treatments? What is also highly recommended?
Prescription products should be reserved for patients with proven infestations that do not respond to proper application of over-the-counter pediculicides
Manual nit removal with a fine comb may be used as an adjuvant to topical therapy
What is the 2 first line therapy for lice infestation? What are the pt directions?
Permethrin 1% (Nix): Apply to dry hair, and rinse after 10 minutes Repeat in 1-2 weeks
OR
Pyrethrins with piperonyl butoxide (RID, Pronto): Apply to dry hair, and rinse after 10 minutes Repeat in 1-2 weeks.
What are the 5 rx strength lice treatment options? Which ones are the off label use?
Spinosad
Malathion 0.5% lotion (Ovide)
**Permethrin 5% (Elimite)
Ivermectin-formulated lotion (Sklice Lotion)
**Oral ivermectin (off-label use)
** off label use
What are the pt directions for Spinosad? What age range?
Applied as a 10-minute treatment if live lice are seen at 1 week there should be a second treatment
Combing of the hair is NOT necessary, as this agent is ovicidal
adults and children older than 4 years
______ is the first-line lice treatment by the American Academy of Pediatrics
Spinosad
Which lice tx agent is combing of the hair NOT necessary? Why?
Spinosad
because the agent is ovicidal
What are the pt directions for Malathion?
Apply to dry hair, and rinse after 8-12 hours
A repeat application is recommended after 1-2 weeks.
What are the pt directions for Permethrin 5%? **What age range?
Apply to dry hair, and rinse after 8-12 hours Repeat in 1-2 weeks
**CI in infants aged younger than 2 months.
What is the pt education for Ivermectin-formulated lotion? What pt population?
The treatment is applied for 10 minutes
Adults and in children aged 6 months and older 🡪 it should not be used in babies younger than 6 months or in pregnant women
What is the pt education for Oral ivermectin (off-label use)? What pt population?
200 micrograms/kg in one oral dose and repeat in 7-10 days
Not indicated in children aged younger than 5 years or weighing less than 15 kg
What is the tx if the lice infestation involves the eyelids?
Application of petrolatum twice daily to the eyelid margins for at least 8 days is recommended
What is the technical name for body lice? What organism?
Pediculosis Corporis
Pediculus humanus corporis
How big are body lice? Where are they commonly found? What will you see on PE?
2-4 mm, wingless, blood-sucking arthropod
Rarely found on the skin, as they live in and lay eggs on CLOTHING
The bites leave behind macules and
papules concentrated in the
intertriginous regions, very itching especially at NIGHT when they move from the clothing to body to feed
What am I? What am I associated with? What parts of the body am I more likely to be found?
pediculosis corporis
Associated with poor hygiene, poverty, and homelessness
Found anywhere on the body but are most concentrated in areas covered by clothing: groin, axillae, trunk, and buttocks
What are Maculae cerulea? What are they associated with?
blue-gray macules
lice infestation
Body louse infestation is sometimes referred to as ______. What is it?
“vagabond disease”
(parasitic melanoderma) = thickened and darkened skin after a long period of bites and scratching or rubbing
What is the best test for pediculosis corporis?
Close examination of the patient’s clothing for lice, nits, and feces. CLOTHING SEAMS
Wood’s lamp will show fluoresce yellow-green
Can shake pt’s clothing over white paper and use tape to examine what falls out
What are the 3 arthropod-borne diseases transmitted by P. humanus corporis?
Typhus (Rickettsia prowazekii)
Relapsing fever (Borrelia recurrentis)
Trench fever (Bartonella quintana)
can test for any/all of these disease if clinical suspicion is high
What is the environmental and person tx for pediculosis corporis?
Treat clothing and fomites:
All clothing and bed linens should be washed with HOT water and dried using HIGH heat
Discard or avoid using heavily infested items for 2 weeks (seal in plastic bags)
Iron the seams of furniture with a hot iron
person:
For heavy infestation 5% permethrin cream or lotion head-to-toe for 8-14 hours
What is the technical term for pubic lice? How is it transmitted? What is the organism?
Pediculosis Pubis
Highly contagious, sexually transmitted parasitic infestation with the pubic or crab louse but can be spread by close physical contact or clothing
Phthirus pubis
How is pediculosis pubis NOT spread?
NOT spread by household pets
What is a lice infestation called on the eyelashes? Can also be seen on the scalp if the pt has _____. Are pubic lice very mobile?
pediculosis palpebrarum
tightly curled hair
NO! NOT adapted for crawling
How long does it take for Pediculosis Pubis to incubate? What is chitin? How long does it take for the lice to hatch?
1 week from contact
Chitin is a fibrous substance consisting of polysaccharides and forming a major constituent in the exoskeleton of arthropods
Lice hatch in approximately 6-10 days
Why is pediculosis pubis extremely itchy?
This is thought to be secondary to a reaction to the saliva and/or the anticoagulant injected into the skin by the louse during feeding
** What will you see on dermoscopy for pediculosis pubis? What will the nits look like?
Dermoscopy the adult louse is characterized by legs grasping the hair shaft and insertion of mouth parts into the skin
brown and full in shape, indicating the presence of a nymph, or they are translucent and more flat in shape when empty
What are 4 additional signs of pediculosis pubis?
Erythematous macules or papules present at feeding sites
Wheals can be appreciated as an acute reaction
Small pinpoint bleeding on intimate clothing
+/- Inguinal lymph node swelling
What is the best test for dx pediculosis pubis? What is the pt education?
Best Tests Finding the louse or nit is diagnostic
CDC recommends that sexual partners within the prior month should be notified of possible infestation and should be treated and to avoid sexual contact until you have been tx
Condom DO NOT prevent transmission of pubic lice
30% of pts with pubic lice also have ________
concomitant infection with another sexually transmitted infection
need to order labs/screening as indicated
Will shaving the area of pediculosis pubis cure the pt?
Shaving the involved area(s) may help eradicate the lice but is NOT essential to resolve the infection
What is the preferred CDC recommendation for pubis lice?
Permethrin 1% lotion / cream ->Mousse containing pyrethrins
Wash the infested area and towel dry
Apply the product generously to affected areas
Leave product on for the duration indicated on the package label or insert
manually remove nits with hands or comb
______ MOA neurotoxin resulting in respiratory paralysis of parasite. What preg category?
Permethrin (Nix, Elimite)
preg category B
What are the dosing instructions/pt directions for permethrin when using as tx for head lice?
head lice: apply to washed hair, leave 10 min, rinse and comb out nits/eggs; repeat in 7 days if needed
What are the dosing instructions/pt directions for permethrin when using as tx for scabies?
apply cream from jaw-line to toes, leave 8-14 hr, rinse, repeat in 7 days if needed
bathe prior to application: topical agents are more effective on hydrated skin
What are the 2 active ingredients of PTC Rid? What are the MOA of each?
Pyrethrin/piperonyl butoxide
pyrethrin: neurotoxic to parasite
piperonyl butoxide: synergistic to pyrethrin
What are the 2 CI to OTC Rid? What preg categories?
CI: allergic to ragweed
younger than 2
preg cat C
What are the indications for Malathion (Ovide - Rx)? **What is the CI?
head lice
CI: < 6 y/o
______ MOA is neurotoxic by inhibiting cholinesterase. What preg category?
Malathion (Ovide - Rx)
preg category B
What is the dosing for Malathion (Ovide - Rx)? **What is the super important pt education point?
apply to dry hair, leave 8-12 hours, wash thoroughly, remove nits with comb, repeat 7 days if needed
**flammable: do not use heat on hair after application
______ is the LAST RESORT rx for scabes, head/body/pubic lice. **What is the BBW?
Lindane (Kwell)
Black box warning: neurotoxicity (seizures/death) with prolonged application
______ MOA neurotoxicity resulting in seizure & death of parasite. What state can you NOT use it in?
Lindane (Kwell)
California
What populations should you avoid prescribing Lindane in?
Avoid in infants/children
elderly
wt < 50kg
hx of seizure d/o
open skin lesions
severe liver dz
excessive ETOH use
concomitant use of meds that lower seizure threshold
What are the pt directions for application of Lindane?
SEs of ______ include: transient skin irritation, CNS toxicity (dizziness, ataxia, seizure, paresthesias), alopecia, hematuria, aplastic anemia, hepatitis, pulmonary edema. What preg category?
lindane
preg C-> need to pump and dump for 24 hours after use
What organism causes scabies? What populations are more likely to be affected?
caused by the mite Sarcoptes scabiei var. hominis
higher in children, residents of long-term care facilities, and sexually active persons
should think nursing homes and is VERY contagious
How many mites is the typical scabies infestation? Why does it itch? How long does it normally take before the pt starts showing symptoms?
10-20 mites
Hypersensitivity reaction to the mites burrow into and just below the stratum corneum of the epidermis
2-6 weeks after initial infestation
What is the diagnostic sign of scabies? Where on the body will you rarely see it?
burrow is a fine, thread-like line with a terminal tiny (smaller than a pinhead) black speck representing the mite itself
RARELY on head and neck areas
What am I? Where are common places you might find this?
scabies
flexor wrists, around the axillae and areolae, in the interdigital web spaces and umbilicus, and in the genital and buttock regions
marks present on the ______ in women and ____ in men are highly suggestive of scabies. Likely to develop _____ from ______
Areola in women and on the penis and scrotum in men = highly suggestive of scabies
Secondary lesions are due to scratching
T/F: Scabies infestations are typically found by scraping papules or excoriated lesions.
FALSE!! mites are very hard to find in scraping and should look for the burrow and presence of the tiny black dots could be eggs, mites and feces left by the mite
What does a “jetliner with its trail” finding on dermoscopy represent?
A slightly darker, V-shaped structure leading the burrow represents the head of the mite, followed by the burrow
Does a negative scabies prep rule out scabies as the dx?
A negative scabies prep does not rule out this diagnosis mites can be infrequent and difficult to isolate in patients with normal immune function
What is crusted scabies? What 2 pt populations are the most vulnerable?
super high infestation of scabies, usually in thousands to millions. VERY CONTAGIOUS
most often seen in immunocompromised or institutionalized patients
What is the tx for crusted scabies?
topical agent of choice Permethrin 5% full body application left on 8-14 hours (overnight), repeat in 1 week
AND
oral ivermectin 0.2mg/kg/dose on days 1,2,8,9,and 15 (sometimes also on day 22 and 29)
What am I? What is the best test?
crusted scabies
scabies prep
What is the step by step procedure to perform a scabies prep? What about crusted scabies?
Place a small amount of mineral oil on the skin area to be tested, a #15 blade, and a microscope slide take the blade and gently remove the terminal end of the burrow where you see the tiny black speck
Apply this scraping to a glass slide, cover with a cover slip, and examine under the microscope for the presence of the mite or its ova or fecal pellets, known as scybala
**In cases of crusted scabies, add a few drops of 10% potassium hydroxide (KOH) solution to the skin scraping to break down the excess keratin. Scales will typically contain many mites
What is the tx for scabies?
Firstline - permethrin 5% or Rid
Doesn’t work -> then lindane
treat infested person and close physical contact, even if asymptomatic
repeat tx in 1 week
What should you NOT use in crusted scabies? Why?
avoid lindane in crusted scabies- increased risk of CNS toxicity
What is the 2nd line tx for scabies? What is the dosing frequency?
Oral ivermectin: 0.2mg/kg/dose po q2weeks (2nd line)
2-3 doses separated by 1-2 weeks for heavy infestation
What is the pt education for scabies regarding symptoms?
symptoms should improve within 3 day but pruritus can persist for up to 4 weeks after tx
can use benedryl to help with itching symptoms at night
or super severe -> oral prednisone
What 2 diagnosis indicate a skin scraping?
scabies or fungal infections
What is the technique for a scabies skin scraping? What should you add for crusted scabies?
apply 1-2 drops of mineral oil to the burrow
use scalpel perpendicular to skin, scrape multiple burrows (>15)
smear specimen on slide
-crusted scabies: add 10% KOH to skin scraping to dissolve excess keratin
seal with slide cover
examine under microscope with low and high power
What is the technique for a fungal skin scraping?
use scalpel to remove scale along border of the lesion
transfer to slide, apply 1-2 drops of 10-20% potassium hydroxide (KOH) to slide
allow to sit for 10-15 minutes
examine under microscope with low and high power
Although tarantulas have venom, they usually cause illness from their ______
urticating hairs
Black widow spiders are members of the _____ genus. What is their scientific name? Where are they commonly found?
Latrodectus genus
Lactrodectus mactans
woodpiles
What are some s/s of a neurotoxic venom from a black widow spider bite?
Painful hypertension, tachycardia, palpitations, diaphoresis, anxiety, shortness of breath, hyperthermia or hypothermia, excessive salivation, nausea, vomiting, and severe abdominal pain
Describe a spider bite in words? **What does a female black widow look like?
Noticeable fang marks with development of a halo-like lesion around the bite
Female black widow spiders can easily be identified by the characteristic red hourglass figure present on their ventral abdomen
What am I?
spider bite
What genus are recluse spiders? What is their scientific name? What will their bites look like?
Loxosceles
Loxosceles recluse
Pain, swelling, bullae, and ischemia develop minutes to hours later
Eventually ulcerate and become necrotic and gangrenous
think more necrosis than systemic symptoms
______ can occur with recluse spider bites. Describe the spider
DIC = disseminated intravascular coagulation
violin-shaped figure spanning its dorsal head and thorax
What am I?
brown recluse spider bite
What am I?
brown recluse spider bite
What am I? Where am I commonly found? What is the scientific name?
Funnel-Web Spiders
Pacific Northwest
Tegenaria agrestis
Is the bite of a brown recluse spider initially painful? Funnel-web spider?
Brown recluse: NO
Funnel-web spider: YES
What will a funnel-web spider bite feel like?
The venom of this spider is neurotoxic, capable of producing severe pain at the bite site and systemic symptoms
may cause necrotic skin lesions
What family are tarantulas? What will their bites feel like? Why are they a problem?
Theraphosidae
relatively harmless bites
urticating hairs from their abdomens, resulting in local skin reactions, ocular problems, and allergic rhinitis
When looking for a spider bite, what s/s would clue you in?
2 small puncta, the fang marks of the spider
Erythema and edema
Necrotic or dusky center within a red, inflammatory plaque is characteristic
In brown recluse spider bites _____ and ____ present early. Between 12-24 hours after envenomation, _____, ____ and _____ develops. **What is the name of this sign?
vesicles and bullae form
erythema, ischemia, and necrosis
**“red, white, and blue” sign = brown recluse spider bite
Describe the bite of black widow spider
local sweating, piloerection, redness, and mild edema
SYSTEMIC symptoms!!: muscle pain, cramps, abdominal pain, salivation, lacrimation, sweating, and tremors are more prominent than the skin findings
**What is the gold standard test for spider bites?
**Spider collection with positive identification
There are no tests in widespread clinical use to diagnose spider envenomation
If systemic involvement due to a brown recluse spider bite is suspected, check for evidence of _____. If systemic involvement is present, _____ and ______ levels should be followed. What 3 things should you monitor for?
hemolysis
serial hemoglobin
plasma-free haptoglobin
rhabdomyolysis, renal failure, and disseminated intravascular coagulation
What is the tx for a spider bite?
wound irritation
Rest, cold compresses, elevation of the affected extremity.
treat pain as indicated
update tetanus shot
Conservative local debridement of clearly necrotic tissu
Antivenom as indicated
necrotic lesions: +/- dapsone (controversial)
