Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Those Mangy Dogs!

Pet Column for the week of October 10, 2011

Related information:

Related site - Dermatology Services at the Veterinary Teaching Hospital
Services - Dermatology

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Brittany Way Rose
Information Specialist

The term "mangy dog" has been applied to dirty dogs, dogs that look unkempt, and even dogs that are misbehaving. But what exactly does "mangy" mean?

Dr. Domenico Santoro, a board-certified dermatologist at the University of Illinois Veterinary Teaching Hospital in Urbana, explains that dogs can become "mangy" when they contract a disease called mange, or "scabies."

There are two kinds of mange: sarcoptic mange and demodectic mange. Both diseases are caused by mites, but the two manifest in very different ways.

Sarcoptic mange is a highly contagious disease. It can quickly spread to all your pets. This disease is caused by a Sarcoptes mite. Infected animals have intense itching on the skin of the face, legs, and abdomen. It is thought the mite by-products cause the intense itching. The scratching can cause crusts to form on the abdomen, elbows, and floppy portion of the ears. The crusting can often cause thickened skin.

The sudden development of intense itchiness generally leads to the diagnosis of sarcoptic mange. The mites themselves are often very hard to find on skin scraping. Veterinarians may use other tests, such as repeated extensive skin scrapings and fecal flotations, to confirm the diagnosis by finding mites and their eggs. Veterinarians may treat a pet for this disease based on a strong suspicion of scabies, and confirm the diagnosis if the condition responds to treatment.

Sarcoptic mange is typically treated with an acaricide, dip such as a lime-sulfur dip, to kill the mites. Often dips are performed three or four times seven days apart. There are sprays or other topical products that may also help eliminate the mites.

Demodectic mange is entirely different, according to Dr. Santoro. Demodex mites live inside the hair follicles, not on the skin surface. Small numbers of these mites are part of the normal flora of your pet, but large numbers can cause redness, flaking, crusting, and hair loss. Like sarcoptic mange, demodectic mange also occurs on the face, legs and abdomen, but can be much more generalized and severe than sarcoptic mange.

Demodectic mange in puppies is the result of a very specific defect in the immune system. It usually produces little to no itching and mainly hair loss. In adult animals, demodex can arise in conjunction with immunosuppressive disease or administration of immunosuppressive drugs. Many times in the adult form there is an underlying disease that must also be treated to help treat the demodectic mange. Finding this underlying, immunosuppressive disease is often very difficult, which makes the mange difficult to treat.

Diagnosis can be made from deep scraping the hair follicles and finding mites, eggs, or larvae. Further diagnostics must be done to identify the underlying disease in adult dogs.

The two forms of demodectic mange require different treatment approaches. Puppy demodex often resolves spontaneously and doesn't need treatment unless is generalized. Adult demodex can be treated with bathing in benzoyl peroxide and clipping of the affected areas, if localized. However, anti-parasitic drugs need to be used in treatment of generalized demodectic mange. Amitraz body dips every two weeks or other topical or oral medication may be prescribed until your pet has two negative skin scrapes at one-month intervals.

If you suspect your animal is becoming a "mangy dog," it's time to check in with your local veterinarian.