Demedectic Mange
Demodectic Mange
(Sometimes called Red Mange)
The Culprit -
Demodex CanisDemodectic mange is caused by a microscopic mite called Demodex canis. All dogs raised normally by their mothers possess this mite. For some reason, conditions change in certain dogs to allow demodex mites to gain the upper hand; the mites proliferate and can cause serious skin disease.
- Mites are not transmitted to people or other dogs except from mother dog to pup as described. Demodectic mange (unlike sarcoptic mange) is not contagious.
- Mites live inside hair follicles -- a difficult place for miticides (chemicals that kill mites) to reach.
- Mites are a normal residents of dog skin; it is only in some individual dogs that mites cause problems.
Demodicosis -- The Disease Itself
Demodectic mange, also called demodicosis, has three forms:
Usually a red, scaly, well-circumscribed lesion on the face or forelegs is present. It generally goes away on its own. Goodwinol ointment, an insecticide, may be used daily to control localized demodicosis. Hair regrowth should be evident after about a month of treatment; however, some localized cases appear "destined" to become generalized and no treatment will prevent this from occurring.
When ointment is used, rubbing the medication on the area may break off the weaker hairs at the margin of the lesion. The lesion may thus appear to get larger at first. Often it is best not to treat this condition and to simply allow it to resolve on its own.
Localized demodicosis is almost exclusively a "puppyhood" disease. When a puppy develops localized demodicosis the chance of the condition resolving are 90% unless there is a family history of demodicosis in related dogs. In this case, chance of spontaneous resolution drops to 50%.
The entire dog is affected with patchy fur, skin infections, bald, scaly skin.
- Most generalized demodicosis starts as localized demodicosis.
It is very important that dogs with a history of generalized demodectic mange not be bred as there is a hereditary component to the development of the disease.
This condition represents demodectic mange confined to the paws. Bacterial infectious usually accompany this condition. Often as generalized demodicosis is treated, the foot is the last stronghold of the mite. Old English Sheepdogs and Shar-peis tend to get severe forms of this condition. The infection can be so deep that biopsy is needed to find the mites and make the diagnosis.
Stress and Generalized Demodectic Mange
The younger the dog, the better the chance of cure. In many cases of adult-onset demodicosis, the disease is controlled by dips and baths but cure is not always possible. Some cases can never be controlled.
- Females should be spayed as soon as the disease is controlled. Coming into heat, hormone fluxes, and pregnancy are very stressful. Also, predisposition to demodicosis is hereditary and should not be passed on.
- The dog should be fed a reputable brand of dog food so as to avoid any nutritionally related problems.
- Keep the pet parasite-free. Worms are irritants that the pet need not deal with and fleas may exacerbate the itchiness and skin infection.
- Keep up the pet's vaccinations.
- The mites themselves cause suppression of the immune system so the pet needs every advantage to stay healthy.
- Skin infections are usually present in these cases and antibiotics will likely be necessary. It is very important that cortisone type medications such as prednisone NOT be used in these cases as they will tip the immune balance in favor of the mite.
Prognosis
Current Treatment of Choice -- Ivermectin
THIS MEDICATION IS NOT SAFE FOR USE IN COLLIES, SHETLAND SHEEPDOGS, USTRALIAN SHEPHERDS, OLD ENGLISH SHEEPDOGS, AND SOME WOULD SAY, ANY HERDING BREED.
Recently a DNA test has been developed by Washington State University which can determine whether or not an individual has ivermectin sensitivity. (The test uses a cheek swab - for details visit
Affected dog needs to be appropriately rechecked at the proper intervals so that the mite numbers can be checked and it can be determined if the dose should be increased.
Traditional Treatment -- Amitraz (Mitaban) Dips
Ivermectinis a broad spectrum anti-parasite medication generally used for food animals and horses. In dogs and cats it is licensed for use as a heartworm preventive aand as a topical ear mite therapy; the use of this medication to treat demodicosis is not approved by the FDA. Ivermectin is highly effective and is considered the rreatment of choice. Ivermectin is inexpensive and involves no labor intensive bathing. www.vetmed.wsu.edu/vcpl). Not all individuals of collie heritage are sensitive to ivermectin.|
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Unless the animal is largely bald or has a short coat, complete clipping will be required for maximal contact with the dip.
The pet's skin is scraped every 2 weeks until 2 consecutive scrapings are negative. Dipping/bathing is discontinued and the pet is rechecked in one month. Dipping/bathing are reinstituted if mites are again found.
Amitraz dipping should not be used in toy breeds or in very young puppies.
Something Else Your Veterinarian Might Try -- Interceptor®
Interceptor may be used in any patient safely; the only downside is expense.
Relapse is always a possibility with generalized demodicosis but most dogs that relapse do so within a 6 to 12 month period from the time they appear to have achieved cure. When relapse occurs it is often because the dog appeared to be normal and the owner did not return for the appropriate rescrapings. The final scrape is performed one month after treatment has stopped. Interceptor (active ingredient: Milbemycin oxime) is normally marketed as a monthly heartworm preventive; when it is used on a daily basis, it is effective against generalized demodicosis. This discovery was welcomed by the veterinary profession as finally demodicosis could be treated without labor-intensive dipping. The downside to this treatment is expense, plus an owner can expect to be using this medication daily for up to 3 months to achieve cure.
Physiological stress is an important factor determining the degree of severity of demodectic mange.