Skin Sampling Flashcards
What sampling techniques are used for derm?
- skin scrapes
- wood’s lamp
- coat brushing
- hair plucks
- cytology
- tape strips
- smears
- culture
- biopsy
What can be demonstrated using skin scrapes?
- ectoparasites (esp mites)
- dermatophytes
- nematodes
What size blade should be used for skin scrapes?
No. 10
What can be demonstrated using Wood’s lamp?
Certain spp of dermatophyte (most commonly Microsporum canis in vet species)
What can be demonstrated using hair plucks?
- Ectoparasites (demodex, esp on feet; lice and mites, eggs ‘nits’)
- Dermatophytes (Hair structure)
What can be demonstrated using coat brushing?
superficial ectoparasites esp Cheyletiella and flea feaces
What can be demonstrated using tape strips?
- superficial ectoparsites or microbes, esp yeast (Malasezzia: peanut shaped)
What can be demonstrated using smears?
- cytology (good for ears, inflammatory lesions, masses)
- microbes (staph or pseudomonas most commonly)
What can be demonstrated using biopsy?
- histopath features
- sample for culture
- dont crush sample!!
Which derm pathology are Italian Spinonis predisposed to?
Otitis Externa
How should skin scrapes/microscope slides be examined?
Methodical exam!!! Snake up and down (marks for this is OSCES)
When is skin biopsy indicated?
- neoplasia suspected
- if dx can only be made by histopath
- unusual/severe clinical signs
- persistent ulceration
- no response to initial measures
- expensive/hazardous tx considered
Which lesions should be selected for skin biopsy?
> spontaneous, early lesions - macules, papules, nodules - pustules, vesicles, bullae > avoid damaged lesion - excoriated, scarred - post-inflammatory pigmentation
How should the skin site be prepared for biopsy?
- do NOT Surgically prepare! (removes diagnostic features)
> exception: tissue culture of nodules - do not crush sample
- 10% buffered formalin immediately, >20x specimen volume
- remove infection/infestation first? (bacteria/fleas/malasezzia)
What size punch biopsies should be used?
- 6/8mm routinely
- 4mm foot pads/nasal planum
- 8mm large lesions
- AVOID NORMAL SKIN!*
ie. do not aim for ‘margins’
