SARCOPTIC MANGE

(ALSO CALLED "SCABIES") 

APPEARANCE OF THE DISEASE

The motion of the mite in and on the skin is extremely itchy. Further, the presence of burrowed mites and their eggs generates a massive inflammatory response in the skin which creates yet more itchiness.

Mites prefer hairless skin thus leaving the ear flaps, elbows and abdomen at highest risk for the red, scaly itchy skin that characterizes sarcoptic mange. It should be noted that this pattern of itching is similar to that found with airborne allergies (atopy) as well as with food allergies. Frequently, before attempting to sort out allergies, a veterinarian will simply treat a patient for sarcoptic mange as a precaution. It is easy to be led down the wrong path and pursue allergy aggressively if sarcoptic mange is considered too unusual or unlikely.

As the infection progresses, eventually most of the dog's body will be involved. Classically, though, the picture begins on the ears (especially the ear margins), the elbows, and abdomen.

The term "scabies" refers to mite infestations by either Sarcoptes scabiei or other closely related mite species. While Sarcoptes scabiei can infect humans and cats, it tends not to persist on these hosts. When people - including some veterinarians - refer to "sarcoptic mange" or "scabies" in a cat, they are usually referring to infection by Notoedres cati, a mite closely related to Sarcoptes scabiei. In these feline cases, it would be more correct to refer to "notoedric mange," though the treatment for both mites is largely the same. Notoedric mange, in cats, generally produces facial itching and scabbing.

For more information on notoedric mange, click here.

HOW THE INFECTION IS SPREAD

Sarcoptic mange mites are usually spread by direct contact from host to host. While mites can live off of a host for days to weeks depending on their life stage, they are only infective in the environment for 36 hours, which means that decontamination of the environment is generally not necessary.

Mite infections on humans are self-limiting (i.e., they go away on their own) as the mite is not able to complete its life cycle on the "wrong" host. The condition is extremely itchy, though, while it lasts. The mites are most active where skin is warm, such as in bed or where clothing is snug.

IF A SARCOPTIC MANGE ANIMAL IS PRESENT IN THE HOME,
IT IS A GOOD IDEA TO WASH ANY BEDDING IN
THE WASHING MACHINE (OR REPLACE WITH NEW BEDDING),
AND WASH ANY COLLARS OR HARNESSES.

DIAGNOSIS

SKIN SCRAPING – Classically, mite infection is diagnosed by scraping the skin surface with a scalpel blade and examining the skin debris under a microscope for the presence of mites. If the mite’s presence is confirmed by skin scraping, then one knows immediately the cause of the itching and other conditions need not be pursued.

When an animal with sarcoptic mange scratches itself, it breaks open the tunnels that the mites have burrowed into and the mites are killed (though the itch persists due to toxins in the skin). The result is that the mites can be very difficult to confirm by skin scraping tests. (Probably mites are confirmed in 50% or fewer of sarcoptic mange cases).

MEDICATION TRIAL - Since negative test results do not rule out mite infection, a "Maybe Mange" test is frequently performed. This consists simply of treating for sarcoptic mange and observing for resolution of the signs within 2-4 weeks. Treatment is very simple and highly successful in most cases so it is fairly easy to rule out sarcoptic mange with a trial course of medication. See below for treatment options.

BIOPSY - Mange mites are rarely seen on a skin biopsy sample, though, if the sample is read out by a pathologist who specializes in reading skin samples, the type of inflammation seen in the sample can be highly suggestive of sarcoptic mange. As a general rule, if skin is biopsied, it is best for the veterinarian to request that a dermatohistopathologist read the sample.

TREATMENT

While sarcoptic mange is difficult to diagnose definitively, it is fairly easy to treat and a number of choices are available.

REMEMBER, ALL DOGS IN A HOUSEHOLD WHERE
SARCOPTIC MANGE HAS BEEN DIAGNOSED
SHOULD BE TREATED.

ISOXAZOLINE INSECTICIDES (NEXGARD^®, SIMPARICA^®, BRAVECTO^®, CREDELIO^®) - Recently this group of oral (Bravecto is also available as a topical) flea and tick products have come on the parasite control market. They are not FDA approved for treating sarcoptic mange but they turn out to be effective for it anyway. A single treatment at the usual dose is generally adequate to clear sarcoptic mange mites. Now that we have regular flea control products that are also effective on sarcoptic mange, the more classical prescription medications seem to be falling by the wayside.

IVERMECTIN - Ivermectin is the prototype of the aforementioned classical prescription medications used against sarcoptic mange. It is one of the most effective treatments against Sarcoptes scabiei yet it is off-label as far as the FDA is concerned. Now that there are FDA-Approved treatments, ivermectin is not used nearly as much but we include it because the approved treatments are mostly derived from ivermectin and because ivermectin is still commonly used. There are several protocols because of the long activity of this drug in the body.

Typically an injection is given either weekly or every two weeks in one to four doses. There are issues with toxicity in dogs that possess the MDR-1 mutation (usually collie-type breeds). These issues are avoided by using the FDA-Approved products but for more information on cautions with ivermectin, click the link above.

SELAMECTIN (REVOLUTION^®) - Selamectin is an ivermectin derivative marketed in the dog for the control of fleas, ticks, heartworm, ear mites and sarcoptic mange mites. Normal monthly use of this product should prevent a sarcoptic mange problem but to clear an actual infection studies show an extra dose is usually needed after 2 weeks for reliable results. Because this product is approved for use against sarcoptic mange, the MDR-1 mutation does not come into play.

Click here for more information from the manufacturer on Revolution.

MOXIDECTIN (ADVANTAGE MULTI^®, CORAXIS^®) – Moxidectin is another ivermectin derivative. It is applied on the skin but is absorbed into the body to act against heartworm larvae, hookworm, roundworm, whipworm In Advantage Multi^® it is combined with imidocloprid to also cover fleas while in Coraxis^®, it is meant as a topically applied dewormer. Moxidectin is not approved for use against sarcoptic mange in the U.S. but is approved for this use in other countries.

Click here for more information from the manufacturer on Advantage Multi.

MILBEMYCIN OXIME (INTERCEPTOR^®, SENTINEL^®, OR TRIFEXIS^®) - Milbemycin oxime is approved for heartworm prevention as a monthly oral treatment. Happily, it also has activity against sarcoptic mange and several protocols have been recommended by different dermatologists. This is another medication that one might find recommended.  There are many brands available.

DIPPING - Here, a mite-killing dip is applied to the pet usually following a therapeutic shampoo. Mitaban dip (Amitraz), or Lime-Sulfur dips given weekly are usually effective. Disease typically resolves within one month.  Dipping is labor intensive and rarely done any more as the other products are easier and more rapidly effective. We mention dipping since it has been a standard mange treatment for decades prior to the introduction of ivermectin. 

IN THE MEANTIME

During the time it takes to control the mite infection, the pet will be very itchy. Control of secondary bacterial infections with antibiotics is important. Also, since the body's reaction to the mite is one of hypersensitivity (essentially an allergic reaction), a cortisone-derivative is worthwhile to quell the itchiest symptoms. Ask your vet about whether either such prescription is appropriate for your pet. As for anti-itch shampoos, rinses, and other forms of itch relief, please visit out Relief of Itch page for further suggestions.

HUMAN DISEASE

Sarcoptes scabei most certainly can be transmitted from dog to human. Transmission is by direct touch such as petting and snuggling or sharing bedding with the dog. There are also human varieties of Sarcoptes scabei which are transmitted from human to human readily with no dog involved so when a person is diagnosed with "scabies" the dog is not necessarily the culprit; in fact, most human scabies does not involve pet transmission at all and is completely different from the canine condition above. For more information on human scabies, visit:

http://www.cdc.gov/parasites/scabies/gen_info/faqs.html

Page last updated: 5/7/2021