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Mange: It Mite Not Be So Bad


Pet Column for the week of April 29, 2002

Related information:

Services - Dermatology

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

Mange has a bad reputation for being a contagious skin disease that is very difficult to treat. Just the word conjures images of massive hair loss and ceaseless itching, yet many people don't even know what causes it.

Mange is caused by mites, which are arachnids (same family as spiders) that can live on the skin. Demodex, probably the most common species of mite, is naturally found on the skin of dogs in small numbers.

"When these mites become too numerous, they can cause problems such as hair loss, scabby skin, and occasionally mild itchiness," says Dr. Jennifer Matousek, a veterinary dermatologist at the University of Illinois Veterinary Teaching Hospital in Urbana. "In young dogs mange is usually a problem related to an inherited immune defect that prevents the puppy from fighting off the infection, while in older dogs, increased numbers usually indicate some underlying problem that has weakened the dog's immune system, allowing the mites to multiply out of control."

The mites could also multiply excessively if the dog was receiving some kind of medication that suppresses the immune system, such as topical medications containing steroids.

Treatment for Demodex was once very expensive with limited results, which may be one of the reasons that mange has gotten such a bad reputation. These days, the treatment for this problem is easier and much more effective, making it possible to get these mites under control.

One of the most important facts for pet owners to know about this particular kind of mite is that it is not contagious to people or other animals. Dr. Matousek says, "Demodex cannot even spread from dog to dog, so there is no need to treat anyone else in the household."

The other mites most commonly found affecting dogs are Sarcoptes (also known as scabies) and Cheyletiella. These mites are very similar, and both are contagious to other animals and to humans. "These mites seem to be concentrated in different regions of the country," says Dr. Matousek. "While some regions have large numbers of Cheyletiella, Sarcoptes seems to be most prevalent in other areas. For instance, it seems that veterinarians in Chicago see more Cheyletiella, whereas we see more Sarcoptes in Champaign."

Both of these mites are usually transmitted by contact with other animals, especially wildlife such as foxes. These wild animals can also contaminate the environment when they come into the back yard. The best way to avoid getting these mites is to keep dogs away from wild animals and unfamiliar dogs.

Unlike Demodex, Cheyletiella and Sarcoptes are not normally found on the skin and their presence is not related to the dog's ability to fight off infections. "You may see larger numbers of these mites if the dog has a problem with its immune system," says Dr. Matousek, "but immunosuppression does not make it more likely that the dog will get these mites."

These mites cause hair loss, yellow crusts on the skin, and itchiness. While these mites are more unpleasant than Demodex, they can be removed much more readily. Dr. Matousek says, "Demodex can take months of treatment to resolve, but Sarcoptes and Cheyletiella can usually be completely removed in only 3 to 6 weeks."

Sarcoptes mites are contagious to people, so owners who have dogs with these mites may need to be treated too. On people, they often accumulate in places where clothes fit tightly, such as at waistbands. People do not usually require treatment for Cheyletiella mites, but they can bite and cause transient itching before they die and fall away. Human infection by either Sarcoptes or Cheyletiella is not usually a serious health problem but can cause discomfort.

If you know that your pet has an infestation of Sarcoptes or Cheyletiella and think that you may have contracted the mites too, then you should seek attention from a physician. If you have any questions about mange or any other skin diseases, please contact your local veterinarian.