Dermatology Diagnostics, Topical therapy Flashcards
flea detection
- areas of focus
- flip technique
- “The Florida Triangle”: rear end to mid back
- “Flip technique”: flip animal quickly, look for scooting fleas on belly
<><> - coat brushing: Flea debris, eggs, mites
> Brush debris from haircoat onto paper
> Tap debris to centre
> Pick up debris using CLEAR tape
> Place on slide with a drop of mineral oil
> Put mineral oil on the tape, making a tape sandwich with mineral oil on either side
> and then place a cover slip
> Examine as you would a skin scraping for flea debris, eggs, mites
<><> - Tape can also be used directly to collect more superficial dwelling parasites (e.g. Cheyletiella)
Skin scraping for mites
- Place mineral oil on microscope slide or
place mineral oil directly on the site to be scraped - Use a dull scalpel blade (I usually dull it on a
tongue depressor) - keep the blade perpendicular to the skin
- Squeeze skin and get good deep scrapings for Demodex
where to scrape for demodex
- and species specific considerations
- Erythematous patches
- Scaly skin/follicular casts
- alopecic patches /macules
- Hyperpigmented regions / comedones (blue skin)
<><>
D. gatoi?
> Interscapular
> A different cat
<><>
D. cati – head, neck ear swab
<><>
Seborrheic (greasy) regions (D. injai)
<><>
Pododemodicosis
> Sedation
> Biopsy
Skin Scraping tips - Demodex (vs other mites)
- Scrape while squeezing the skin intermittently, and continue until you get capillary bleeding (for demodicosis; can be more superficial for Sarcoptes and Cheyletiella)
- Smear the sample onto a microscope slide with mineral oil on it (“like “buttering bread”)
- Get enough of a sample to make a diagnosis
<><> - Use lots of mineral oil to reduce oil slicks
- Cover slip
- 10X objective; every field; look for motility;
- Lower condenser – aids contrast;
<><>
when to use hair plucking to search for mites?
- how?
- demodex tips and considerations
- for hard to scrape areas
- pluck quickly to reduce discomfort
- Lots of hairs spread out over slide (goal: 100)
<><>
Hair Plucks for Demodex mites:
TIP:
> Don’t squeeze here!
> Pluck in the direction of hair growth
Demodex: Skin scraping vs Tape collection technique?
Acetate tape impression with skin squeezing was found to be more sensitive than deep skin scraping and is an alternative diagnostic method for canine demodicosis.
Acetate tape for Demodex - technique
- apply tape and run with firm pressure
- squeeze the skin under the tape
- Place on slide with a drop of mineral oil
- Put mineral oil on the tape, making a tape sandwich with mineral oil on either side
- and then place a cover slip
- Examine as you would a skin scraping
how to identify sarcoptes
- legs: sucker on end of long unjointed stalk
Sarcoptes
- human risk?
- site predilection
- dx
Zoonosis
> absence of pruritus in other pets or people does not rule it out
<><>
Site predilection:
> pinnal margins, elbows, ventrum, hocks
<><>
Diagnosis
> Multiple superficial skin scrapings
– can be tough to find…..
Steroid treatment - An Aid in the Diagnosis of Sarcoptic Mange?
- immunomodulatory drugs were associated with a significant increase in the pruritus level but not with the mean number of lesional body sites
- 20.5% higher rate of positive skin scrapings
- (but low number of dogs in study)
Take home message for scabies with steroid treatments:
Rule out/treat for scabies or treat for it whenever considering steroids
demodex canis
- larva morphology
- nymph morphology
- egg morphology
egg:
> pregnant banana
<><>
Larva:
> 3 pairs of legs
> Shorter body than adult
<><>
Nymph
> Shorter body compared to adult
> 4 pairs of stubby legs
<><><><>
Adult > eggs > larva > nymph
Demodex gatoi
- transmission
- who gets it?
- lesions
- sites on body
- associations
- Contagious!
- Young, short-haired cats
- Erythema, excoriations, scaling and crusting
- Head, neck, elbows, flanks, ventrum, rear legs
- Geography?
- Association with allergic skin disease (steroids?)
demodex gatoi appearance
- short and stubby
demodex injai appearance
- looooooong
