My female dog is suffering from a terrible case of Demodex mange. We've tried medicated shampoo, antibiotics, Mitaban, and ivermectin solution, all with no improvement. She is now smelly, bloody, and miserable from scratching. Her entire body, face and feet are involved. Her fur is falling out rapidly. She looks, feels and smells awful. Is there any hope she will fully recover?
Demodicosis (red mange) is a canine skin condition that occurs when abnormally high numbers of a particular mite (Demodex canis) multiply on the affected dog's skin. Demodex mites are normally present in small numbers on the skin of healthy dogs. When a dog's immune system becomes weakened, the mites can overgrow, causing disease and inflammation of the skin. There are two types of demodicosis: localized and generalized.
Nursing puppies commonly become infected with these mites. The mites can be passed from the mother to the nursing puppies because puppies have weak and underdeveloped immune systems that allow the mites to overgrow. Typically, affected puppies under six months old have the localized type of demodicosis. The mites usually appear on the front legs and face. Hair loss is common, with red, scaly bald patches of skin present in the infected areas. The skin may or may not be itchy. Most localized cases are mild and heal without treatment.
Generalized demodicosis, in contrast, is a far more serious disease, especially when it starts in dogs four or five years of age. Affected dogs will at first develop multiple small areas of hair loss, scaling and redness. These areas subsequently get larger until the entire body is affected. Generalized demodicosis causes severe skin irritation. Secondary bacterial infections that are often resistant to antibiotic treatment commonly occur, making treatment almost impossible. As the disease progresses, the skin may become covered with infected, pus-filled, crusty, bloody erosions and ulcers.
Diagnosis is based on the affected dog's history, the findings of a physical examination, and the results of a microscopic evaluation of skin scrapings from affected parts of the dog's skin. In generalized demodicosis, the veterinarian will perform additional tests to determine the underlying cause for the dog's immune system disorder. The underlying cause may be cancer or immune system-suppressing medications.
When demodicosis is localized in puppies, no treatment is usually needed; healing typically occurs in six to eight weeks. In a few cases minimal treatment may be beneficial. Generalized demodicosis requires long-term intensive treatment, including topically applied amitraz (Mitaban) solution available from a veterinarian. Treatment of the underlying immune system disorder is also indicated. The intensive use of oral ivermectin has been reported to be helpful in more than 80 percent of dogs that are difficult to treat; however, these dogs may require treatment for months (10 to 40 weeks) before the skin scraping test shows no live mites or eggs. Ivermectin use in demodicosis is an "extra-label" use in the United States. This means that ivermectin is not licensed by the Food and Drug Administration as a treatment for this disease.
Many times generalized demodicosis can only be controlled and not cured. The prognosis for recovery from generalized demodicosis in dogs over two years old is poor.
Keeping animals in good health can prevent demodicosis. Regular visits to the veterinarian will help maintain the dog's overall health and detect underlying conditions that could weaken the dog's immune system. Regular de-worming and vaccinations are also important.
09/09/03
