CANINE DEMODECTIC MANGE
(SOMETIMES CALLED "RED MANGE" OR “DEMODICOSIS”)
FOR INFORMATION ON DEMODECTIC MANGE IN THE CAT: FELINE DEMODECTIC MANGE
THE CULPRIT - DEMODEX CANIS
DEMODICOSIS HAS THREE FORMS
FORM #1: LOCALIZED
CAN THE PUP BE BRED LATER?
Sometimes the puppy with localized demodicosis was obtained for breeding purposes. The current recommendation is not to treat these puppies so that we can determine if the condition will stay localized and resolve or if it will generalize. If it stays localized and eventually resolves without treatment, the animal is still a candidate for breeding. If the condition generalizes to cover the entire body, the animal should be sterilized. If the condition receives treatment and resolves, we will never know how the disease would have gone in its natural state and will not know whether the pup is carrying the genetic predisposition for generalized demodectic mange. In this case, it is best to be conservative and not take the chance of passing on genetic predisposition for this disease.
Localized demodicosis is almost exclusively a "puppyhood" disease. When a puppy develops localized demodicosis the chance of the condition resolving is 90% unless there is a family history of demodicosis in related dogs. In this case, chance of spontaneous resolution drops to 50%.
Occasionally an adult dog develops localized demodicosis. We currently do not have good understanding of the prognosis or significance of this condition in an adult dog.
JUVENILE ONSET -- Young dogs that develop demodicosis are believed to have a genetic immunological defect that allows the mite to gain the upper hand. As the puppy grows up and his or her immune system matures, the immune system tend to naturally regain control of their mite infestation; in fact, 30-50% of dogs under age 1 year recover spontaneously from generalized demodicosis without any form of treatment. Usually treatment is recommended, though, to facilitate recovery.
IT IS VERY IMPORTANT THAT DOGS WITH A HISTORY OF GENERALIZED
TREATMENT: STRESS AND GENERALIZED DEMODECTIC MANGE
The treatment of demodicosis only in part relies on medications; some basic steps can be taken with regard to pet care to maximize the chance of success. Physiological stress is an important factor determining the degree of severity of demodectic mange and the following steps should be taken to reduce stress:
TREATMENT: MEDICATIONS (MACROCYCLIC LACTONES)
CURRENT TREATMENT OF CHOICE -- IVERMECTIN
Ivermectin is a broad spectrum anti-parasite medication that is FDA-approved for the treatment of numerous parasite conditions. Its use in the treatment of demodicosis, however, is not FDA-approved. Before ivermectin was available, the only treatment for demodicosis was dipping (see below) which is labor intensive and not without side effects. The advent of ivermectin has changed the prognosis of demodicosis entirely. Ivermectin is inexpensive and easy to give by mouth or as injection. Daily or every other day dosing is usually necessary and most patients achieve cure or at least control of their disease. (Note that the weekly ivermectin protocols that work for other parasites do not work on Demodex mites.)
That said, there is an important caveat: Some individual dogs, those with the MDR1 mutation, are sensitive to ivermectin and can die if subjected to a typical therapeutic dose for demodicosis. In most cases, ivermectin-sensitive dogs are members of the collie-family, Old English Sheepdogs or other herding breeds.
THIS MEDICATION CANNOT BE ASSUMED SAFE FOR
So if there is any question about a dog's heritage, what you should be done to be sure treatment is safe? One way to go is to use a test dose for several days prior to starting the therapeutic dose. A better way is to actually test the dog for the MDR1 mutation since we now have that ability thanks to Washington State University.
For details on testing for ivermectin sensitivity visit:
There is a range of ivermectin doses used in the treatment of demodicosis and it seems that higher doses do clear infection faster than lower doses. This means that if a lower dose has been ineffective, a higher dose may still work. This does not mean that a pet owner should experiment with ivermectin doses on their own as there is some potential for lethal toxicity if this drug is not used appropriately.
The doses of ivermectin used in the treatment of demodicosis are not compatible with the commonly used flea product spinosad (Comfortis® or Trifexis®). The combination of spinosad and high doses of ivermectin will increase the likelihood of ivermectin neurologic side effects. While flea control is very important during the treatment of demodectic mange, a different product should be used.
Another important caveat concerns heartworm. The high doses of ivermectin needed to kill Demodex mites will rapidly kill circulating larval heartworms in a heartworm infected dog. The sudden death of a large number of worms in the bloodstream can lead to shock so it is important to verify that the patient is heartworm negative in dogs that are old enough that heartworm infection is possible. Heartworm requires a good 6-7 months to establish an infection so younger puppies are not at risk for this reaction.
For more information on Ivermectin, click here.
MILBEMYCIN OXIME (SENTINEL®, MILBEMAX®)
Milbemycin oxime is a macrocyclic lactone like ivermectin and it seems to be just as effective as ivermectin in treating demodicosis. Even better, it has a much broader safety margin with MDR1 mutation dogs. Milbemycin oxime was originally introduced to the small animal market as a heartworm product called Interceptor® which has since been discontinued. Tablets came in a 6 pack and were intended for monthly use. Treatment of demodicosis requires daily use, however, and that made the product often prohibitively expensive. Today, Interceptor® is no longer available but milbemycin oxime can be obtained in combination with other dewormers so at least it remains an option.
If the demodicosis patient is a member of a breed suspicious for the MDR1 mutation, it is still recommended to test for the mutation before giving large doses of milbemycin oxime. As with ivermectin, milbemycin oxime will rapidly kill heartworm larvae and potentially lead to shock so it is important to test dogs that are old enough to have a heartworm infection prior to use.
MOXIDECTIN (ADVANTAGE MULTI®)
Moxidectin is another microcyclic lactone that could be used in the treatment of demodicosis (though probably not in ivermectin sensitive animals). In Advantage Multi®, moxidectin is administered topically once a month as a dewormer and heartworm preventive to provide broad spectrum parasite control in combination with imidocloprid for flea protection. Moxidectin has activity against demodex mites and is often effective if used weekly in the treatment of demodectic mange. Results have not been as reliable as those with ivermectin particularly in more severely affected dogs or older dogs.
TRADITIONAL TREATMENT -- AMITRAZ (MITABAN) DIPS
Dip is applied by sponge. Gloves should be worn while applying dip. The dip dries on the dog's fur and should not be rinsed off. The dog should not get wet between dips.
Dipping occasionally yields mild sedation as a side effect. Very small dogs may become highly sedated and require an antidote but this is unusual. For your convenience, dipping and bathing may be performed at the hospital thus allowing for veterinary supervision in the event of side effects.
Dipping/bathing is recommended every two weeks according to the FDA approved label on the bottle of dip. Most universities are finding that the cure rate jumps from 25% to 80% when dip is used at double strength and applied weekly. No toxic effects have been seen using the dip in this way and this is our current recommendation when opting for dips except in very small dogs and puppies.
Dipping is a fair alternative for ivermectin in collie breeds and in ivermectin sensitive individuals.
AMITRAZ DIPPING SHOULD NOT BE USED IN TOY BREEDS
NOTE: Amitraz is a drug of the monoamine oxidase inhibitor class. People who are taking selected serotonin reuptake inhibitors (such as fluoxetine) could have a bad reaction to the use of amitraz if they administer dips to pets. Similarly, pets on SSRI's may have reactions to amitraz. Human diabetics should also avoid administering amitraz dips as amitraz may interfere with glucose regulation; diabetic pets may have trouble as well.
A FEW NOTES ABOUT PROMERIS®
Promeris® is/was a prescription topical flea and tick product also labeled for the control of demodicosis. Its anti-tick active ingredient is amitraz (the same active ingredient in Mitaban® dip described above). The product is typically used every 2-4 weeks to treat demodicosis and has the advantage of being safe for the collie-type breeds (and other individuals with ivermectin sensitivity). Promeris was withdrawn from the market by Pfizer in 2011 because of immune-mediated reactions emerging with regular use for flea and tick control. Still, some product may still be around and in use so we mention it here.
The younger the dog, the better the chance of cure. Most dogs under one year and a half years of age, recover completely from generalized demodicosis. In many cases of adult-onset demodicosis, the disease is controlled with treatment but cure is not always possible. Some cases can never be controlled.
Treatment, no matter which option is chosen, should be accompanied by skin scrapes every 2-4 weeks. In this way the effectiveness of treatment is assessed and modifications of dosing can be made. There are several protocols published describing how to determine if treatment can be stopped. The idea is to eradicate every single mite from the dog's body so that the condition cannot recur. This typically entails either continuing treatment for a significant time after the patient appears recovered and/or rechecking skin scrapes a significant time after treatment has finished.
When relapse occurs it is often because the dog appeared to be normal and the owner did not return for the appropriate re-scrapings. Relapse is always a possibility with generalized demodicosis as there is no easy way to confirm that every mite has been killed but most dogs that relapse do so within a 6-12 month period from the time they appear to have achieved cure.
SARCOPTIC MANGE IS A COMPLETELY DIFFERENT DISEASE.
Click here for information on Sarcoptic mange.
Page last updated: 9/6/2015