Mange (Demodex) Symptoms in Dogs and Cats

Mange (demodex) in dogs and cats causes skin problems. Your pet's skin itches—mildly with localized infection and severely with generalized infection. Some pets scratch until they develop bacterial infections along with demodex infections. The hair falls out and bald spots develop. Bald patches, especially around the eyes, mouth, elbows, and front legs are common. The skin may be rough and dry and is referred to as lichenoid. A summary of mange symptoms in dogs are as follows:

Three forms of mange in dogs and cats

There are three forms of mange (demodex), and signs and symptoms depend upon which form your pet develops:

  • Localized
  • Generalized
  • Limited to the feet (pododermatitis)
Localized Mange

Localized mange (demodex) occurs in only one area, such as on the ear or the face. A few spots in the local area may be affected. Usually the symptoms are mild and clear up on their own. About 10% of pets with localized mange develop generalized mange.

Generalized mange

Generalized mange (demodex) occurs in multiple locations, such as ear, elbow, and stomach, and may progress to cover most of your pet's body, including the feet. Generalized mange occurs in young pets and in adult pets. If it occurs in your adult pet, it suggests your pet has a significant disease or health problem that predisposed him or her to develop widespread mange infection. For example, pets with cancer, hypothyroid disease, allergies, and heartworm infections may develop mange infections.

Pododermatitis (mange of the paws)

Mange (demodex) of your pet's feet (paws) can be a localized infection or part of a generalized infection. Pododermatitis is common in dogs with Bulldog genetics.

Diagnosing mange in pets

Positive diagnosis of mange, or demodex mites, is based on finding a skin scraping with the mites. Your veterinarian may make a presumptive diagnosis of demodex infection even though mites are not found on a scraping if your pet has all the symptoms.

Skin scraping tests

Demodex mites live in hair follicles, so the infection is diagnosed by your veterinarian scraping your pet's skin and looking for the mites in scraped material under a microscope. To increase the likelihood that mites are found, your veterinarian will pinch or squeeze your pet's skin gently before taking the scrapping.

A dull tool, such as the back of a scalpel blade is used to scrape your pet's skin. Because mites are hidden in hair follicles, which are nourished by capillaries, a tiny amount of bleeding occurs if the scraping is deep enough. Finding an occasional mite on a skin scraping is normal, but finding many mites diagnoses an infection—especially if the mites are the immature form, which has six legs. A scraping that does not open some capillaries and bleed a tiny amount is not likely to yield results.

Even with excellent scraping techniques, mites can evade detection, so some veterinarians decide to treat pets even though mites were not found on a scraping.

Other tests used to diagnose mange

Pets that have positive diagnosis of demodex mites by skin scraping often benefit from several other tests:

  • Fecal exams for worms
  • Blood tests for heartworm infection
  • X-rays for tumors
  • Blood tests for kidney and liver function

These tests are helpful because many pets that develop demodex infections have other serious infections or disease. The tests mentioned above help find these problems which can range from cancer and poorly functioning thyroid glands to heartworm infections and intestinal worms. In pets with high white blood counts, veterinarians look for co-existing fungal infections such as blastomycosis or cryptococcosis.