Cat Mange (Feline Scabies)
Feline scabies is an uncommon skin ailment caused by the head mite Notoedres cati. The first sign is intense itching about the head and neck, along with hair loss and the appearance of bald spots. Due to the incessant scratching, the skin becomes red, raw, and excoriated. Typically, you will see thick gray to yellow crusts around the face, neck, and edge of the ears. The condition also may involve the skin of the paws and genitalia.
In severe or untreated cases the skin forms scabs, crusts, and thickened wrinkled skin on the head that gives the cat an aged look. With intense scratching, the wounds become infected.
Severe itching is caused by female mites tunneling a few millimeters under the skin to lay their eggs. Mite eggs hatch in 5 to 10 days. The immature mites develop into adults and begin to lay eggs of their own. The whole cycle takes three to four weeks. The diagnosis is confirmed by skin scrapings, or, in difficult cases, by skin biopsy.
Head mange is highly contagious. It is transmitted primarily by direct
animal-to-animal contact. Dogs and even people can be infested, but only for short periods. Infestation in people produces an itchy skin condition that resolves spontaneously in two to six weeks, if all mites have been eliminated from the cat.
The Notoedres mite will reproduce only on cats. It is highly susceptible to drying and cannot live more than a few days off the host.
Treatment: Clip scabies-affected areas on longhaired cats and bathe the entire animal in warm water and soap to loosen crusts. Kittens may be dipped or shampooed but must be dried quickly to prevent chilling. Kill the head mites by dipping the cat in a 2.5 percent lime sulfur dip weekly. Continue for two weeks beyond apparent cure. Lime sulfur dips are safe for use on pregnant queens and kittens over 6 weeks of age. Other cats on the premises should be dipped once a week for three to four weeks, since they may harbor the mite and act as a reservoir for reinfestation.
An alternative to dips is selamectin (Revolution), with doses given a month apart. Ivermectin is also used by some veterinarians.
Cheyletiella Mange (Walking Dandruff)
This type of mange is caused by a large reddish mite that lives on the skin and causes mild itching with a tremendous amount of dry, scaly material that looks like dandruff. The dandruff is heaviest over the back, neck, and sides. These mites often come in on contaminated bedding such as straw or old newspapers that have been stored in outdoor sheds. This type of mange is not common in cats.
The life cycle of the Cheyletiella mite is similar to that of the head mange mite. The entire life cycle takes four to five weeks. The diagnosis is confirmed by finding the mite in skin scrapings collected on paper and examined under a magnifying glass.
Walking dandruff is highly contagious. Humans can easily become infested. The signs are itching and the appearance of red, raised bumps on the skin. They look much like insect bites, which, in fact, they are. The Cheyletiella mite cannot live off the cat for more than two weeks. The owner's rash should improve as the cat is treated.
Treatment: All cats and dogs on the premises should be treated with a lime sulfur insecticide dip or a shampoo containing a pyrethrin insecticide. Continue to treat for two weeks beyond apparent cure. An alternative treatment is ivermectin.
This noncontagious form of mange is common in dogs, but fortunately, it is rare in cats. The demodex mite is a normal resident of the cat's skin and seldom causes more than mild, localized infection. The exception is in immune-suppressed cats suffering from FeLV, diabetes mellitus, chronic respiratory infection, cancer, or the immune-depressant effects of chemotherapy or excessive hydrocortisone.
The moth-eaten look of hair loss around the eyes is characteristic of localized demodectic mange.
These mites occur frequently in dogs and produce a disease called sarcoptic mange. Fortunately, they are rarely seen in cats. Their effect and treatment is similar to that of head mange. Skin scrapings are used to make the diagnosis. If no mites are found on multiple skin scrapes but other diagnoses have been eliminated, your veterinarian may recommend treatment anyway.
This article is excerpted from “ Cat Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.
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