Skin & Ear Cytology Reference for Dogs and Cats
Reference for common findings on skin and ear cytology - appearance, how each is best identified, and the clinical association for each.
A visual and diagnostic reference, not a substitute for cytology review.
Organism numbers, not just presence, drive treatment decisions - a few cocci or yeast can be normal flora, while high numbers or a symptomatic patient point to active disease.
Organism type
Yeast
Malassezia pachydermatis (yeast)
Appearance
Budding yeast with a distinctive "peanut," "footprint," or bowling-pin shape.
Found via
Skin or ear cytology (tape prep or swab), stained (e.g. Diff-Quik).
Allergic dermatitis, otitis externa, and greasy, malodorous skin; often a secondary overgrowth rather than a primary problem.
Frequently asked questions
Why might a skin scraping be negative even when a dog truly has sarcoptic mange?
Sarcoptes mites are present in very low numbers even in affected animals, so scrapings frequently give false negatives - diagnosis often relies on clinical signs like the characteristic pinna-rub itch reflex and response to treatment, not just a positive scraping.
How do you tell Demodex from Sarcoptes on a skin scraping?
Demodex has a cigar-shaped body with short legs and lives in hair follicles, requiring a DEEP scraping to capillary ooze to find it; Sarcoptes is round/turtle-shaped, lives more superficially, and is found in much lower numbers, making it harder to find even with proper technique.
Why does rod bacteria on ear cytology matter more than cocci?
Rod-shaped bacteria, often gram-negative organisms like Pseudomonas, are more commonly associated with severe, chronic, or antibiotic-resistant otitis and often warrant culture and susceptibility testing, whereas cocci - usually Staphylococcus - are the more common, often more treatable, everyday finding.
Is Demodex overgrowth in an adult dog always primary?
Adult-onset demodicosis, as opposed to the more common juvenile-onset form, should prompt a search for an underlying cause - such as immunosuppressive disease, medication, or endocrine disorder - rather than assuming it's primary.