Skin scraping and ear swab for mites in cats and dogs

What it shows

Mites are tiny arachnids. The vet collects material and looks for mites and their eggs under a microscope. A form can show two lines:

• Skin scraping (ectoparasite screen) — the vet scrapes the skin with a blade and examines the material. For Demodex, which lives deep in hair follicles, the scraping is deep — over a pinched skin fold until a little capillary blood appears; plucked hairs or a skin biopsy can be used instead. For mites that live on the surface — Sarcoptes in dogs, Notoedres in cats and Demodex gatoi in cats — the vet takes several superficial scrapings over large areas. Cheyletiella (“walking dandruff”) is looked for in combed-out scurf or on tape impressions.
• Ear swab for mites — the ear mite Otodectes cynotis can sometimes be seen with an otoscope. Wax and debris from the ear canal are collected on a cotton swab, rolled onto a slide and examined at low magnification.

Higher than reference — what it may be a sign of

• Demodex found in a dog — in canine demodicosis, deep scrapings or plucked hairs usually show mites, eggs and larvae in high numbers. This mite is not considered contagious: puppies get it from their mother while nursing.
• Sarcoptes found in a dog — sarcoptic mange is highly contagious between dogs, by direct contact and through shared combs, brushes, towels and bedding. People in contact with an affected dog can also get an itchy skin reaction; it is usually self-limiting. Questions about the risk for people go to their own doctor.
• Notoedres found in a cat — these mites are usually found quite easily in scrapings, and the disease spreads readily among cats and kittens.
• Ear mites found — typical findings are dark brown waxy discharge and inflamed ear canals. The number of mites matches the signs poorly: a cat with a lot of dark wax may carry only one or two, while another with clean ears may carry many. Mites pass between pets by close contact; human infestation is rare.

Lower than reference

“No mites found” lowers the likelihood but does not always exclude them. This matters most for Sarcoptes in dogs: the sensitivity of skin scrapings may be as low as 20%, and many dogs with scabies have negative scrapings. When scabies is still suspected, the vet may concentrate several scrapings or order a blood antibody test (ELISA) for sarcoptic mange, or choose another way to check the suspicion. In cats, Demodex gatoi mites are often few. In demodicosis in dogs the vet repeats scrapings over time to see how things are going.

Look at together with

• Fungal culture — in cats with demodicosis it is considered essential, because ringworm (dermatophytosis) and demodicosis can occur together; widespread demodicosis in a cat calls for a general medical work-up.
• Faecal flotation — centrifugal flotation may occasionally reveal Sarcoptes mites or eggs.
• Allergy tests — scabies in dogs is often first taken for allergic skin disease, so a negative scraping and allergy results are read together.

Units and conversion

Neither test has a unit. The result is written as “mites found” or “not found” (sometimes “negative”), usually with the mite named — Demodex, Sarcoptes, Notoedres, Otodectes or Cheyletiella. Some forms add which stages were seen and roughly how many. In the app these results are stored as text.

Reference range

The reference range is on your lab’s form; for a healthy animal the expected result is “no mites found”. A negative result is weighed together with the signs and how many sites were sampled.

Cats and dogs

Sources

1. Merck Veterinary Manual — Mange in dogs and cats
2. ESCCAP — Ectoparasites: Acari (mites) in dogs and cats
3. CAPC (Companion Animal Parasite Council) — Otodectic mite guidelines