Demodectic Mange in Dogs

Demodectic mange is a skin disease that affects the hair follicles of adult dogs and puppies. It is often called “red mange”, “puppy mange”, or Demodex. It is the most common form of mange in dogs.

It is important to note that there are two different mange mites which cause skin disease in dogs. One lives under the surface of the skin, while the other lives inside the hair follicles of the skin. Although both mites share similar characteristics, there are significant differences. It is important not to confuse the two types of mange because they have much different causes and treatments.

Signs & Symptoms of Demodectic Mange

Demodectic mange has two forms; localized or generalized.

General signs and symptoms will include:

Hair loss - most commonly around the eyes, muzzle, and various places on the head.
Areas of bare skin will look red and flaky or crusty - these are commonly referred to as lesions.
Localized demodectic mange will usually appear with a few patches of hair loss around the face and head area.
General demodectic mange will usually appear with multiple lesions involving the entire body.

Demodectic mange does not itch severely, even though lesions will be present. You will probably not notice your dog itching and scratching excessively. Demodectic mange is not contagious to other dogs or people. Remember, this mite is normally found in the hair follicles, so therefore exposure to an infected dog is not dangerous.

Causes of Demodectic Mange

Demodectic mange is caused by an ecto-parasite called Demodex canis. This little mite lives in the hair follicles of dogs and it is normal to find small numbers of these on dogs and humans. However, if the immune system is compromised or not fully developed, especially in puppies, these mites increase in population causing a disease called mange. This is why demodectic mange is most commonly seen in dogs less than two years of age. Adult dogs that have Demodex usually have defective immune systems.

Diagnosis of Demodectic Mange

Diagnosis begins with a complete history and a physical exam.

Skin scraping - If your veterinarian suspects any type of mange they will most likely perform a skin scrape. This test involves scraping the skin of a lesion and making the lesion bleed slightly. This will be virtually painless for your dog; the substance scraped will then be put on a slide and examined under a microscope as these mites cannot be seen by the naked eye. A positive scraping test result indicates the presence of mites or mite eggs.

Treatment for Demodectic Mange

The treatment for localized demodectic mange is usually done using topical medications, shampoos, and sometimes dips. In some cases, the localized areas will heal on their own, and won’t require aggressive treatments. The generalized form of this mange requires an extensive dipping schedule with a medicated dip containing Amitraz. This dip should be used with great caution. Most often, these dip treatments are done at your veterinarian’s office. A dipping schedule will vary based on the severity of the mange, but expect to have between 5 and 15 dips performed. You should clip your dog’s hair short prior to dipping, and bath him with a benzoyl peroxide shampoo to remove oil and debris from the skin. Your veterinarian will repeat a skin scraping after the third or fourth dip to determine whether or not the mite population is decreasing. Once you have two negative skin scrapings, the dip treatments can be stopped.

Prevention of Demodectic Mange

Demodectic mange is not a preventable condition. In puppies the mites are passed directly from mother to puppy. If a puppy has an underdeveloped immune system, the mites overpopulate, causing the infection. The treatment of localized and generalized mange is normally quite successful however, if the immune system is defective, treatments can be difficult. In these cases, puppies and adult dogs will need further diagnostic work and more complex treatment plans to address the underlying immune system dysfunction. It is possible to have multiple outbreaks of mange with your dog, but as the immune system strengthens, these become fewer.