Notoedric Mange

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Notoedric Mange

By: Dr. Mark Thompson

Section: Overview

Notoedric mange is a contagious, itchy skin disease of cats caused by infestation with the parasite Notoedres cati. Notoedres cati is a mange mite that is closely related to Sarcoptes canis, the mite that causes sarcoptic mange in dogs. This is a highly contagious disease in cats that is spread by direct contact. The mites can only survive on the animal and can live only a few days off the host. It is considered rare in the United States, although it occurs commonly in certain geographic areas like southern California.

Although it is a parasite that affects cats, this mite can occasionally infest dogs and can cause temporary, minor itching in humans. The mite causes severe pruritus (itching) and infested cats can cause significant harm to their skin by chewing and scratching. The disease begins at the base of the ear and spreads up the ear pinna, around the face, and down the neck.

Eventually, the lesions may reach all the way to the feet and to the anal area, possibly due to the cat's normal grooming behavior.

What to Watch For

Itchiness

Hair loss

Diagnosis

History and physical exam are important because of the typical distribution of the lesions.

The test of choice to confirm the diagnosis of notoedric mange is the skin scrape. The veterinarian uses a scalpel blade to scrape the superficial layers of the skin and then examines the sample that is collected with a microscope. These mites are usually found in large numbers with this test, unlike the canine scabies mite, which is often difficult to find by skin scraping.

If debris is present in the ears, a smear of the debris should be examined under a microscope for the presence of ear mites (Otodectes cyanotis), since these mites may cause similar symptoms.

If mites cannot be found, allergic diseases like atopy and food allergy should be considered and appropriate allergy testing should be done.

Treatment

Weekly lime sulfur dips are very effective and very safe. Medium and longhaired cats should be clipped before dipping to ensure good contact of the dip with the skin. All cats in the house should be treated, as cats that are not symptomatic may be carrying the mite and may reinfest other cats after treatment is completed. The biggest drawback of lime sulfur is its rotten egg smell and the difficulty in dipping some cats.

Amitraz dips have been used successfully in cats for this problem, but this is an unapproved dip for cats and some have shown signs of toxicity.

Ivermectin injections every one to two weeks has shown good success and is certainly more convenient than dipping. This drug is also not approved for cats at the dose that is required to kill mites. However, side effects are rare.

Home Care and Prevention

This mite can only be contracted through contact with an infected animal. Keeping your cats away from stray cats and their environments helps to prevent spread. Be sure to have new cats examined by a veterinarian before bringing them into your household.

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