chapter 5 Practical Cytology.....................................
DEFINITION/OVERVIEW
Cutaneous cytology is an essential diagnostic tool.
Samples should be obtained in almost every dermatologic case.
The technical aspects of sample collection and slide preparation are critical for inter-
pretive value.
Skin scrapings and trichograms, otic swabs/smears, direct impression smears, fine-
needle aspiration, and acetate tape preparation samples are the most frequently
employed cytologic techniques in dermatology.SKIN SCRAPINGS: SUPERFICIAL SAMPLE
To diagnose infestations of sarcoptes, notoedres, cheyletiella,Demodex gatoi,Demodex
cornei,Otodectes.
Select lesional skin.
Place a small amount of mineral oil on a glass slide.
Use a scalpel blade #10 or spatula.
Apply a small amount of mineral oil either to the blade or directly onto the selected
lesional skin (most helpful for sarcoptes).
Scrape the area in the direction of hair growth and transfer accumulated material to
the glass slide (Figure 5.1).
Select several sites for sampling and, in cases of a suspect sarcoptes infestation, sample
a large surface area.
Certain sampling sites may be preferable depending on the suspect clinical diagno-
sis, i.e., sarcoptes – pinnal margins and elbows, demodex – dorsal midline or focal
alopecic sites.Scan the slide using the 10×objective; adjust the microscope diaphragm and/or con-
denser to provide greater contrast.
Note the proportion of live/dead mites and egg/young/adult forms present
(Figure 5.2a).
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dermatology, Third Edition.
Karen Helton Rhodes and Alexander H. Werner.
©2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc.
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