Demodectic mange is a common variety of mange most often seen in young dogs. It is also known as red mange, puppy mange, and follicular mange, and is caused by demodex canis mites. These skin mites live predominantly in hair follicles, and are mostly harmless.
Skin mites of different varieties live on most mammals, including humans, without causing any type of irritation. They are less that 1/100 of an inch long, (about .25 mm.) and are impossible to see without the use of a microscope. Demodex canis mites resemble tiny alligators, and live about 25-30 days. During that time, they mature, mate, and lay the eggs that will lead to the next generation of mites living on the host organism. They can only be transmitted through direct contact from one dog to another, as they cannot survive on other species or off of the host body.
In most dogs, demodex canis mites do not cause any problems, and the dog, and the dog's owners, do not even realize the mites are there, because the mites are not a problem for healthy, mature dogs. The dogs that have a problem with the mites are ones who have low levels of immunity, which is mostly seen in puppies, older dogs, and dogs who have diseases, such as Cushings or heartworms, or even cancer. Puppies most commonly get demodectic mange after getting infected with mites from their mother.
In the majority of cases, dogs with demodectic mange only get a few isolated lesions on their bodies. These lesions are small, and are generally found around the face and lower back. In a small number of cases, there are several larger lesions, possibly covering the entire body of the puppy if it is severe enough. The most common signs of demodectic mange are hair loss, a greasy or damp look, and red, crusty skin. Not all cases cause itchiness, which is usually associated with mange.
Many cases of demodectic mange in puppies will heal themselves by the time the puppy is three to six months of age, at which point the immune system has matured to the point where it can handle the demodex mites. There are, however, some cases that will require treatment. The most common way to treat this type of mange is through topical creams, dips, and shampoos that get rid of mites. There two most common types of these washes contain either benzoyl peroxide or rotenone. Treatment courses usually run two weeks, and are discontinued one a skin scraping reveals that there are no longer any mites in the skin. In a short period of time, the skin will heal, the hair will regrow, and the dog will be considered cured of mange.
Demodectic mange can also affect cats, although it is two different species of mite, demodex cati and demodex gatoi, that causes this infection in cats. The symptoms are mostly the same as the canine version of this condition, with the main difference being that the lesions are also commonly seen on the legs and body, instead of most around the head. Cats who have demodectic mange, which is also called demodicosis in felines, are tested for diabetes, leukemia, and other conditions that could compromise a cat's immune system. The treatment for cats is the same as it is for dogs; vets will prescribe a topical cream, shampoo, or dip to get rid of the mites that are causing the condition. This will be continued until the cat no longer has mites.