MANGE

Mange is a parasitic skin disease caused by microscopic mites. Two different mange mites cause skin disease in dogs. One (the Demodex mite) resides in the hair follicles, while the other (the Sarcoptic mite) lives just under the surface of the skin.

Sarcoptic Mange or Scabies

The presence of the sarcoptic mite causes severe itching which often looks like severe eczema. The dog will chew and scratch its skin constantly. This leads to a loss of large amounts of hair.

Sarcoptes often starts first on the ears and legs, particularly the elbows and hocks, but can rapidly spread over the legs, shoulders, ears and under the abdomen, and on to cover the whole body in severe cases. Eventually the skin will become thickened and will darken due to pigmentation. Affected skin in active areas can seep rancid smelling serum which often becomes secondarily infected with bacteria and fungi.

Sarcoptic mange is highly contagious to other dogs. It is also contagious to humans. The dogs bedding should be discarded or, if this is not possible, it should be washed and then sprayed with a veterinary insecticide. Your veterinary surgeon will advise you and supply the correct one to use. Although the mites are not able to complete their life cycle on people, they will burrow into the skin and cause uncomfortable itching before they finally die.

Diagnosis

Diagnosis is not always easy as the disease looks very much like allergic eczema. Skin scrapings are performed and examined under the microscope for mites or mite eggs.

Treatment

Treatment is with a specific mange wash and is normally done at 1-2 weekly intervals. Two treatments may be all that is required, although sometimes treatment will continue for several months. If bacterial infection is also present, antibiotics will be prescribed.

 

Demodectic Mange

Demodectic mange is sometimes just called Demodex. It is caused by the Demodex mange mite, a parasite which lives in the hair follicles of affected dogs. Under the microscope, this mite appears shaped like an alligator with eight legs. All dogs (and many humans) have a few of these mites on their skin. As long as the body's immune system is functioning, these mites cause no harm.

Demodectic mange magnified under a microscope.

Demodectic mange most often occurs when the dog has an immature immune system, allowing the mites to grow rapidly. Therefore, this disease occurs primarily in dogs aged less than 18 months. In most cases as the dog matures, the immune system also matures. Adult dogs that have the disease usually have defective immune systems.

Since the mite is found on virtually all dogs, exposure of a normal healthy dog to one with demodectic mange is not dangerous.

Signs of the disease

Surprisingly, a dog with demodectic mange does not itch severely, even though it loses hair in patches. Areas of bare skin will be seen. The hair loss usually begins on the face, especially around the eyes. When there are only a few patches of hair loss, it is termed localised demodectic mange. If the disease spreads to many areas of the skin, it becomes generalised demodectic mange. It may become itchy if the skin becomes infected with bacteria or yeasts. We can check for these if necessary.

Diagnosis

Diagnosis is made in most cases by the laboratory examination of skin scrapings as is Sarcoptes. As the mite can get 2-3mm below the skin surface in the follicles, deep scrapings are necessary. Sometimes it may be necessary to take a skin biopsy to confirm infection.

Treatment

The localised form is usually treated with topical medication and clears easily. The generalised form may require more intensive treatment.

Wash with an anti-Demodex shampoo. It is important that the solution is diluted according to instructions on the bottle and scrubbed into all of the skin. It is essential for you to wear gloves while applying the solution. The product can have side effects on the dog and you if not used properly. Some dogs may appear sleepy for a few hours after the bath.

These two treatments are repeated every 5-7 days until the mites are eliminated. This can take anywhere from weeks to several months. We will keep a regular check on you and your dog and advise you when to stop. After the treatment it will be necessary to examine your dog for the presence of live mites or eggs.

Vitamin E can be taken as tablets or capsules and helps stimulate the immune system.

Prognosis

Treatment of the localised form is generally successful. Treatment of the generalised form is also usually successful, but takes time and perseverance. However if the immune system is defective, neither the mites nor the skin infection may respond to treatment.

And Finally...

Demodectic mange can be one of the most frustrating conditions to treat in the dog. In young animals it can keep returning until the immune system is mature enough to keep the mites in check. It is important that you and your veterinary surgeon work together to help keep it under control and ultimately to cure it. We as a profession only want the best in treatment for your dog, and are fully aware that the time involved in the treatment of mange can be frustrating for all involved (including the dog!!). To this end, please keep your appointments and follow up treatments as requested, and if you are frustrated let us know!