This amazing chemical has been used for years as a large animal (farm animal) dewormer.  It is also the active ingredient in the famous Heartworm preventative called Heartgard.  Scientists and practitioners found out that if used IN THE CORRECT DOSE, Ivermectin, either injected or given orally, can kill sarcoptic mites!  This is a fabulous discovery since dogs no longer have to endure chemical dips and sprays to eliminate scabies mites.  The Ivermectin, IN THE CORRECT DOSE, can successfully treat dogs for sarcoptic mites.

Now... here’s the downside:   Some dogs have a genetically determined sensitivity to Ivermectin!

FROM THE WASHI8NGTON STATE UNIVERSITY VETERINARY SCHOOL website: It is well known that Collies and related breeds can have adverse reactions to drugs such as ivermectin, loperamide (Imodium®), and others. It was previously unknown why some individual dogs were sensitive and others were not. Advances in molecular biology at the Veterinary Clinical Pharmacology Laboratory at Washington State University's College of Veterinary Medicine have led to the discovery of the cause of multi-drug sensitivity in affected dogs. The problem is due to a mutation in the multi-drug resistance gene (MDR1). This gene encodes a protein, P-glycoprotein, that is responsible for pumping many drugs and other toxins out of the brain. Dogs with the mutant gene can not pump some drugs out of the brain as a normal dog would, which may result in abnormal neurologic signs. The result may be an illness requiring an extended hospital stay--or even death.

A test has recently been developed at Washington State University to screen for the presence of the mutant gene*. Instead of avoiding drugs such as ivermectin in known susceptible breeds, veterinarians can now determine if a dog is normal, in which case the drug can be administered or abnormal, in which case an alternative treatment can be given.  Owners and breeders can submit samples for testing. All that is needed for the test is a cheek brush sample that can be obtained by the owner and sent by mail for analysis.

Affected Breeds
Approximately 3 of every 4 Collies in the United States have the mutant MDR1 gene. The frequency is about the same in France and Australia, so it is likely that most Collies worldwide have the mutation. The MDR1 mutation has also been found in Shetland Sheepdogs (Shelties). Australian Shepherds, Old English Sheepdogs, German Shepherds, Long-haired Whippets, Silken Windhounds, and a variety of mixed breed dogs.

The only way to know if an individual dog has the mutant MDR1 gene is to have the dog tested. As more dogs are tested, more breeds will probably be added to the list of affected breeds.

Ivermectin is not approved to be used in this manner.  So your veterinarian should let you know this prior to getting your permission to utilize Ivermectin therapy in the treatment of scabies in dogs and cats.  You can retain some confidence to know that it is in common usage, and has been for a number of years, for the treatment of scabies in pets.  It simply has not been tested by the manufacturer and approved by the FDA to be used in this manner.  You are on your own, you and your veterinarian, in the decision-making arena regarding whether or not to use it to treat sarcoptic mites.   Your alternative is to use insecticide dips and sprays.  Additionally, if the wrong dosage is given, the pet can have a very serious and even fatal reaction to Ivermectin.   The correct dose MUST be given and great care taken not to give too much.

All pets in contact with an affected animal should be treated since there can be asymptomatic carriers (they have the disorder but aren’t showing any signs of disease) of the sarcoptic mites. Pfizer Animal Health has released a new product called Revolution that is approved for use on dogs for the elimination of Sarcoptic mites.  Be sure to ask your veterinarian about this.

There are a number of treatments available to eliminate Sarcoptic Mites from dogs and the veterinarian will decide which may be best for each individual case.  All dogs with scabies mites need to be on a high quality, meat-based diet... and many will benefit from supplements such as Vitamins and Fatty acids.  See PetFoodDirect.com for home delivery of skin specific supplements and Vitamins... plus an excellent breakdown of many pet diets and their ingredient lists.

If your dog is being treated over and over (unsuccessfully) for "allergies" with cortisone products and has never had Sarcoptic Mites actually ruled out as a possible cause of the skin condition, ask your veterinarian about the advisability of a trial treatment for scabies... just in case.

Click to enlarge the images below that show actual cases of sarcoptic mites
Scabies on the elbow of a dog	View a movie of the PINNA-PEDAL Reflex... a way to make a presumptive diagnosis of Sarcoptic Mites in a dog By scratching at the edges of the pinna margins (ear flap edges), the doctor is able to elicit a reflex scratching motion... mites are highly likely! Double-click on the left button to see a movie of a dog with sarcoptic mites.
Same patient, more skin lesions

 

Click to enlarge the images below that show actual cases of sarcoptic mites
Ear margins are common sites for sarcoptic mite infestation	Damaged pinna due to long term sarcoptic mite infestation	Notches seen in damaged pinna due to long term sarcoptic mite infestation	Elbow and lower front limb skin lesions	Another ear lesion

More photos of ear problems from Sarcoptic mites (scabies) in a dog...

Quite commonly the ear margins are the most notably affected places the sarcoptic mites choose to damage.  The ear tips and edges are very pruritic (itchy), develop crusts, dry out and bleed.  Fly bite lesions are often similar but the hallmark of scabies is itchiness. Scabies, though, may affect any area of the skin.