Demodicosis in Cats – Causes, Symptoms & Treatment


Demodicosis in cats

What is demodicosis?

Demodicosis is a skin disease caused by the Demodex mite. There are two species, Demodex cati and Demodex gatoi which infect cats.

  • Demodex cati is long and slim, living within the hair follicles.
  • Demodex gatoi is shorter, living within the surface layers of your cat’s skin.

Demodicosis is quite common in dogs, but rare in cats and when it does occur, it is usually seen in cats who are immunocompromised or who are malnourished. Diseases such as diabetes, hyperadrenocorticism (Cushing’s syndrome), feline leukemia virus, feline immunodeficiency virus and use of immunosuppressive drugs can all predispose your cat to developing demodicosis. Demodicosis may be localised (one or several small patches) or generalised (over a larger part of the cat’s body).

The life cycle of these mites is 20-35 days and is spent entirely on the host. There are no age, sex or breed predilections. It can be transmitted from cat to cat through direct transmission but not cat to human. Most cats remain unsymptomatic, however, those who are immunosuppressed can go on to develop clinical signs of demodicosis.

What are the symptoms of demodicosis in cats?

  • Single or multiple areas of alopecia with crusting and scaly looking patches of skin on the balding areas. The head, ears, and neck are most commonly affected areas, but it can occur elsewhere.
  • Generalised demodicosis may also occur with large areas of symmetrical thinning of the hair or alopecia along with patchy areas on the head, neck and ears and crusting, fluid-filled sores.
  • A waxy secretion may be produced by the ears in response to mite infection along with comedones.
  • Itching.
  • Cats may overgroom, resulting in widespread hair loss.

Diagnosing demodicosis: 

Demodicosis in cats
Image Nottingham Vet School, Flickr

Diagnosis of demodicosis is made by skin scrapings and swabs from the ears which are examined under a microscope. Mites can often be hard to find, and several scrapings from various parts of the body may be necessary. The mite can often be found in fecal material, when ingested during grooming.

Test all cats from the household, even if they are non-symptomatic.

Additional tests may be necessary to check for underlying immunosuppressive disease. This may include FIV and FeLV tests, complete blood count, biochemical profile and urinalysis which can evaluate organ function.

Treating demodicosis:

Spontaneous remission may occur in untreated cats. Especially those with localised demodicosis.

  • Lime sulfur dips or shampoos for four to six weeks. Continue dips until skin scraping tests return negative.
  • Amitraz is an insecticide which can kill the mites. This is toxic to cats, therefore use great care and closely monitor your cat.

Other treatments may include the following:

  • Daily or weekly oral Ivermectin for four weeks. Ivermectin is not approved for use in cats, and there is a risk of side effects, therefore close monitoring are necessary.
  • Treat or manage the underlying cause (if one is found).
  • Wash bedding and blankets in very hot water, hang in the sun to dry.
  • Treat all cats in the household.

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