Lecture 4: Dermatology II Flashcards
When using flea comb, comb through coat in with the direction of __
hair
how can you differentiate dirt vs flea dirt
smear on wet paper towel and flea dirt will leave red streak
what is diascopy, how do you do it/what looking for
- Press glass slide against skin
- If dilated vessels then skin will blanch (erythema)
- If blood leaked into skin, then will not blanch (petechiae, ecchymoses)
what is Dariers sign/how do
urticarial response caused by pressure on skin
Pressure on skin causes hive response
what do you commonly do dariers test/dariers sign for
horses, urticaria, pigmentosa, MCT
what is nikolskys sign/how do
rotating pressure with a tip of pencil or finger causes epidermal separation
what diseases would likely have nikolskys sign
immune mediated diseases like epidermolysis bullnose
what dermatophyte spp is positive under woods lamp
microsporum can is
t or f: some drugs and ointments may fluoresce under woods lamp= false positive
true
woods lamp is not a definitive dx but good for __
monitoring treatment
what do you clean microscope lenses with
lens paper not kimwipes
use __X with __ for bacteria and yeast evaluation under microscope
100x with oil
how Does KOH prep work/what used for
- Add 1-2 drops of KPH applied to hair pluck or skin scrape followed by cover slip and let sit
- KOH will remove epidermal cells/debris allowing to see dermatophytes more easily
where do you scrape for skin scrape
- Areas of hair loss +/- erythema
- Comedones
- Ear margins and elbows if crust or hair loss
How do you do superficial skin scrape
- Place oil on skin
- Scrape indirection of hair in broad strokes 10-15 times
- Turn wrist upward at end to collect material and oil then place on slide
how do you do deep skin scrape
- Pinch area to be scrapped
- Place oil on skin and scrape in direction of hair until light superficial bleeding occurs
- Turn wrist upward at end to collect material and oil then place on slide
t or f: need stain to look at skin scrapes
false
t or f: leave diaphragm open for best evaluation of skin scapes
false- close for better contrast exposure
What are tape preps good for
- Dry lesions
- Seborrhea
- Folds/greasy neck, face, paws
how do you do tape prep
- Place slide into purple stain (no tape)
- Lay on flat counter and add tape on top of slide
- Press firmly
- Turn over slide press firmly to remove excess stain
what is a trichogram
evaluation of plucked hairs
how do you do trichogram
- Pluck hairs with forceps or fingers
- Place in mineral oil
- Examine under 4x and 10x
what stage of hair growth in 1-2 and what is seen in 3
- Anagen
- Telogen
- Melanin clumping
trichograms are good for evaluating what
dermatophyte infection
what are arrows pointing at
ectothrix spores
how do you stain for cytology
- 20-30 seconds in blue, red, and purple stain
- Softly rinse with water
- Blot gently
Where do you sample for bacteria in superficial pyoderma
- Papules/pustules
- Crusts- underneath
- Epidermal collarette
- Moth eaten hair coat
where do you sample for bacteria in deep pyoderma
- Nodules
- Ulcers
- Draining tracts
- Hemorrhagic bulla
where do you sample for yeast
- Dry or greasy scaling skin
- Skin thickening
- Yeasty odor
- Erythema
- Hyperpigmentation
- Salivary stained hairs
how do you do surface scraping
- Use dry dull blade
- No oil
- Smash and smear on slide
- Stain
what samples do you do impression smears on
- Pustules
- Crusts- skin under crusts
- Moist areas
what are cotton top applicators good for sampling
- Folds
- Ear exudate
what are the wooden end of cotton tip applicators good for
- Dry samples
- Nail beds
what is +1-4 and TNTC bacteria quantification mean for bacteria
+1= rare to scattered
+2= many in every field
+3= difficult to count
+4= monolayer of bacteria
TNTC= too numerous to count
how do you quantify yeasts
count average per oil immersion field
2-5/oif
5-10/oif
10-20/oif
TNTC
when do you do bacterial culture and sensitivity
- Rod shaped bacteria on skin cytology
- Failure to respond to appropriate therapy
- Recurrent pyoderma
- Owner is immunocompromised
- Service/therapy dog
what samples are best for bacterial culture and sensitivity
- Pustules are best
- Collarette/crust
t or f: necessary to stop antimicrobials before culture
false
Where do you want to sample for ear cultures
junction of vertical and horizontal canal
where do you want to sample for skin cultures
exudate, pustule or under spreading edge of epidermal collarette
__culture and sensitivity is sufficient in most cases
aerobic
how do you do deep tissue culture
- Scrub surface
- Punch biopsy
- Place in dry white top tube
what culture is best for dermatophyte
DTM
dermatophyte test medium has a __color indicator. If grows __ color colonies and turns __ color then positive
phenol red, white/tan, red
how do you do toothbrush technique for DTM sample
- New toothbrush
- > 20 strokes
- Sample non-lesional skin first
- Inoculate plate
how long do DTM tests take
3 weeks
DTM results: important to monitor __ for __ and __ change
daily, growth and color change
t or f: growth= infection with DTM
false- contaminants
what result
positive
what result for DTM
Negative- contaminant- colonies should be white/tan, color changed but colonies are green/black
what is next step once you have growth on DTM plate
- Use clear tape and press tape on colony
- Add lactophenol blue or purple diff quick
what dermatophyte is this
microsporum can is
What dermatophyte is this
M. Gypseum
what dermatophyte is this
trichophyton
how do you do skin biopsy
- No prep of skin
- Block with lidocaine- bleb up area
- Punch biopsy
- Close with crucial or simple interrupted
t or f: serum testing is reliable for food allergies
false
true or f: hair/saliva testing is bogus for food allergies
true
what is only way to determine if food allergy
elimination diet trial
how do you do food trial for allergies
- Pure novel protein/carb diet
- Avoid protein similar to previously fed
- Avoid all treats, supplements, flavored medications
- 8 week minimum
t or f: allergen testing dx atopy
false- helping treat atopy- identify allergens for inclusion in immunotherapy
how does serology work with allergen testing
measures allergen specific IgE in circulation
what does intradermal allergy testing measure
direct measure of immediate reaction- more sensitive than serology based
what drugs must patient not be on for intradermal allergy testing
- Antihistamines- 2 weeks
- Topical steroids- 2 weeks
- Oral steroids- 4 weeks
- Injectable steroids- depo-medrol 8 weeks
- Apoquel: 2 days
