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Sarcoptic Mange

The mite that causes mange is Sarcoptes Scabiei.

The life cycle of the mite is usually between 17 - 21 days. The adults breed in a moulting pocket on the surface of the skin and once fertilized the female starts to excavate a burrow through the horny layer of the skin at a rate of 2 - 3 mm a day. While burrowing the female mite lays her eggs behind her and leaves fecal deposits as she goes. Once the eggs hatch as larvae they burrow to the surface of the skin where they travel around the animal’s body feeding, eventually resting in a moulting pocket. A new generation of mites will be produced every three weeks. Since the mites prefer skin with little hair, as the condition worsens and more hair is lost, the mites will eventually colonize the whole of the body. The mite Sarcoptes Scabiei are fairly host specific, although they will try and attack other hosts for periods of time.

The mite’s activity causes the skin to react and this causes the animal to bite and scratch constantly, self inflicting open wounds and secondary bacterial infection often follows. All the scratching and biting opens the burrow and once the female mite is exposed she dies. The eggs and faecal debris left behind continue to cause itching which in turn causes more self mutilation, more females to die, more itching, more self mutilation etc etc.

This intense irritation is often made worse by heat. A animal suffering from mange will often act abnormally. It will walk around constantly biting and scratching at the irritation. In most cases the mange starts at the posterior end of the animal.


Question and answer

What is sarcoptic mange?

Sarcoptic mange is a highly contagious, parasitic skin disease of dogs. It is a nonseasonal disorder caused by infestation of sarcoptic mange mites. The mites burrow through the upper surface of the skin and cause intense itching and irritation. The mites secrete substances (allergens) that produce an allergic or hypersensitivity reaction in some dogs.

What causes sarcoptic mange?

Sarcoptic mange is caused by infestation of the mite, Sarcoptes scabiei. Sarcoptic mange is contagious. The infestation follows exposure to a dog with sarcoptic mange. Roaming dogs and dogs living outside are potential carriers of the disease. The dog can be exposed to sarcoptic mange mites at shelters or kennels and during visits to grooming facilities or veterinary offices.

The sarcoptic mange mite can cause skin problems in human family members that come into contact with a dog infested with Sarcoptes. People who come in close contact with an affected dog may develop an itchy rash with small raised bumps (papules) on their arms, chest, or abdomen. Rashes in people usually are temporary and should resolve after the affected dog has been treated. Any affected person should contact a physician regarding possible treatment.

What are the signs of sarcoptic mange?

Sarcoptic mange is a very itchy condition. The pet will have hair loss and a red rash. The signs generally are seen on the elbows, hocks, abdomen, and chest. Scaling and crusting may be present on the ears. Rubbing the ears will cause the dog to scratch with its hind leg. The dog will scratch, leading to sores (skin excoriations) on the skin. Pus-filled lesions may develop. Occasionally, the lymph nodes will enlarge.

How is sarcoptic mange diagnosed?

Sarcoptic mange is diagnosed primarily upon history of exposure to other dogs (generally two-to-six weeks before the skin problems) and physical examination. The veterinarian will want to differentiate sarcoptic mange from other conditions with similar signs, such as food or flea allergies. Examination of skin scrapings may be attempted to identify the mange mite, but false negative results are common. Examination of the stool may reveal mites or eggs. Since it frequently is difficult to find the mange mites on the dog, the pet will be treated for sarcoptic mange based on the veterinarian's suspicion. If the dog's signs resolve following treatment for sarcoptic mange, the diagnosis is made based on the dog's response to treatment.

How is sarcoptic mange treated?

Sarcoptic mange is treated by killing the mange mites on the dog. A topical product has been approved by the FDA to treat sarcoptic mange. Other treatments include medicated shampoo baths followed by body dips. The dips include lime sulfur or pesticides approved for use against the sarcoptic mange mite. Baths and dips usually are done once weekly and continued for two weeks beyond remission of signs. When dips are used, the entire dog must be dipped, including the dog's face and ears, and the dog cannot be allowed to get wet between treatments. The veterinarian will choose the appropriate treatment for each case and will explain the use of the selected products. Instructions for use of these products should be followed carefully. Other medications may be prescribed; some dogs benefit from steroids. Antibiotics may be needed if the skin lesions contain pus, indicating possible infection. In homes with several dogs, all dogs should be treated, even those with no signs because they may be carriers; and it can take one month for signs to develop.

What is the prognosis for dogs with sarcoptic mange?

With proper treatment, the prognosis (outcome) for dogs with sarcoptic mange is good. Response to treatment should be seen within two weeks, although treatment will need to be continued for two weeks beyond remission of signs.

The information on this page was obtained from the site www.vetmedcenter.com