Dermatological diagnostic tests Flashcards
What is coat combing/brushing used to diagnose?
- Surface parasites + fleas
- +/- coverslip
What is acetate tape strip (unstained) used to diagnose?
- surface parasites (e.g. Cheyletiella, D cornei, D gatoi)
- into liquid paraffin + coverslip
- x4-10 objective needed
What are deep skin scrapings used to diagnose?
- Deep parasites (e.g. Sarcoptes, D canis, D injai, D cati
- into liquid paraffin + coverslip
- x4-10 objective needed
What are superficial skin scrapings used to diagnose?
- surface parasites, e.g. D cornei (dogs), D gatoi (cats), Cheyletiella, Sarcoptes
- into liquid paraffin + coverslip
- x4-10 objective needed
What are trichograms used to diagnose?
Parasites:
- Demodex canis/catis
- Louse
- Cheyletiella eggs
Microbes:
- Dermatophytes on shaft (low sensitivity)
Hair structure:
- Anlagen/telogen bulbs
- Shaft/tip abnormalities
- into liquid paraffin + coverslip
- x4-40 objective needed
What is cytology (stained tape strip/impression smear/ear smear) used to diagnose?
Microbes
- bacteria
- yeasts
Other cells
- e.g. inflammatory/epithelial/neoplastic
x4-100 (oil) - not expecting to see bacteria until under oil microscopy
What is Wood’s lamp used to diagnose?
- can detect some Microsporum canis
What is McKenzie coat brushing used to diagnose?
- Dermatophytes for culture
What is microbiological swab for culture used to diagnose?
- bacteria
- yeasts
How to rule out microbial infection
- cytology (used to diagnosis and monitoring tx)
What sample would you take for a dry skin lesion?
- stained acetate tape strip
- e.g. for scale, erythema, lichenification, non-greasy skin folds, interdigital skin
What sample would you take for a wet/greasy lesion that is accessible with slide?
- direct impression smear
- i.e. press slide onto lesion
What sample would you take for a wet/greasy lesion that is inaccessible with slide?
- indirect impression smear
- e.g. using cotton bud in ear canal
- roll onto slide, don’t drag
