FCP Dermatology Practical Recap Flashcards
When do you do cytology in dermatology?
- In all dermatology cases
- Bacterial and fungal infections are suspected
- On nodules and tumours
- Otitis externa
- Autoimmune or immune-mediated diseases
What is a direct smear and what can be examined with this?
Gently pressing the a glass onto the surface of a skin lesion.
Erosions, ulcers, exudate, pustules and papules.
Pustules and papules are
opened gently with a 23G needle
What is an indirect smear and what can is examine?
Involve taking an impression of the underside of a crust, or excised tumour, on a glass slide
What are tape strips and what do they examine?
Crusts, scaling, alopecia,
lichenification and erythematous skin.
Gently press a strip of clear tape onto the skin surface to sample the surface cells.
Stain and view under microscope.
Can be used in areas difficult to get a direct impression smear e.g. interdigital space
What are swab smears and what do they examine?
Use a cotton bud to collect material
Transfer material onto the glass slide by gently rolling cotton bud onto the surface
What are the steps of a fine needle aspirate?
Obtained using a 23G needle
Pass needle through the skin into the abscess,
nodule or tumour
Move in and out in several directions without
leaving the skin.
Remove and attach to a
2.5ml syringe already filled with air
Transfer the contents from the needle onto the
glass slide by pushing the plunger
Depending on the amount obtained the
sample can be spread out using another slide
(i.e like making a blood smear) or spread in
different directions using a needle
When should you do a superficial skin scrape?
- All pruritic animals
- Scaling dermatosis
What can you find on a superficial skin scrape?
Cheyletiella sp.
Notoedres cati
Otodectes cynotis
Trombicula autumnalis
Dermatophyte spores
When to do a deep skin scrape?
- Cases of alopecia (with or without pruritic)
- Greasy skin, comedones, crusting, applies and pustules.
How to do a superficial skin scrape?
Gently clip the area to be scraped if needed/
Apply mineral oil to the area either using a
number 10 blade or a dropper
Scrape at about 45 ̊ angle in the direction of
hair growth repeatedly until scale and surface
material are dislodged
Collect the material and place onto a slide
with more mineral oil
Always apply coverslip before microscope
examination
Examine under x4 or x10
What can you find on a deep skin scrape?
Demodex mites
Sarcoptes scabiei var. canis
How do you do a deep skin scrape?
Gently clip the area to be scraped if needed
Apply mineral oil to the area either using a
number 10 blade or a dropper
Scrape at about 45 ̊ angle in the direction of
hair growth repeatedly until you get capillary
bleeding
Collect the material and place onto a slide
with more mineral oil
Always apply coverslip before microscope
examination
Close the condenser
Examine under x4 or x10
Where do you normally scrape for sarcoptes?
Ear margins, elbows, hocks and ventral abdomen
Where do your normally scared for demodex mites?
Edges of alopecic skin, comedones, erythema,
papules, pustules and crusts
What is trichography?
Hair plucking which is then examined under a microscope.
