Most of us have heard the term “mangy mutt”, and perhaps even used it ourselves once or twice (although hopefully as a term of endearment!) But when it comes to mange, a skin disease caused by microscopic mites that can affect both dogs and cats, there is certainly nothing endearing about it.
There are 2 types of mites responsible for causing mange. One species lives just under the skin’s surface, while the other resides deep within hair follicles. It’s important to distinguish between them, since they cause different symptoms and have different treatments and prognoses.
Since mange is much more common in dogs (and rare in cats), let’s talk about the 2 main types of mange found in dogs.
Sarcoptic mange, also known as “scabies”, is caused by the oval-shaped mite Sarcoptes scabiei. These mites burrow under the surface of the skin, creating microscopic tunnels. Females lay eggs in the tunnels, and once the eggs hatch and the larvae reach adulthood and mate, the whole 2-week cycle begins again.
Sarcoptic mange is highly contagious. These mites can survive in a warm, moist environment for up to 3 weeks without a host, and are easily spread between dogs, from dogs to other pets, and from dogs to, yes, humans.
Symptoms of Sarcoptic Mange
The action of these mites chewing and burrowing their way through the skin causes intense itching in whoever is unlucky enough to become infected. Dogs with scabies typically have red lesions on their face, elbows, legs, ears, chest and abdomen, and the skin appears crusty. Itching can be so intense that dogs will literally scratch until their skin is raw, leaving them vulnerable to secondary bacterial infections.
Dogs can also experience hair loss, reddened skin, sores, and scabs that spread across their entire body. Their skin can darken in color, and they may experience enlarged lymph nodes.
If passed to humans, sarcoptic mites cause an itchy rash of small, red bumps. However, since humans are not their natural hosts, the mites usually die off within a few days.
Diagnosis of Sarcoptic Mange
If you suspect your dog has sarcoptic mange, it’s important to act quickly since these mites are so contagious. Your veterinarian will perform a skin scraping, using a scalpel blade to gently scrape the skin. The resulting skin cells and debris are then examined under a microscope for mites and/or eggs.
However, finding sarcoptic mites on a skin scraping can be tricky. When an infected dog vigorously scratches himself, he breaks open the tunnels in the skin that house the mites, and the mites can be torn apart to the point where they are unidentifiable under a microscope. Fewer than 50% of skin scrapings will show definitive evidence of sarcoptes mites.
Therefore, if a skin scraping is negative (but a dog has classic symptoms of sarcoptic mange), the veterinarian may go ahead and treat the dog for scabies anyway for about 2-3 weeks to see if symptoms resolve.
Treatment for Sarcoptic Mange
Fortunately, sarcoptes mites are fairly easy to kill. There are 2 main options for treatment:
These include Mitaban (Amitraz), Paramite (an organophosphate), or 2% Lime-Sulfur dip. Once a week the dog is bathed, then the dip is applied to his entire body, including face and ears. It usually takes 6-8 weeks of treatment for symptoms to resolve.
Keep in mind these dips can be toxic (to both dogs and humans) and very strong-smelling, and must be used with caution since they can cause serious side effects. Many veterinarians are moving away from using chemical dips due to their potential for toxicity.
Ivermectin is an anti-parasite medication currently licensed for use in dogs and cats as a heartworm preventive. However, it is not yet approved by the FDA for use in treating mange, so any use in that regard is off-label.
However, many vets consider Ivermectin the treatment of choice for mange, since it is considered safer than chemical dips and can be administered either by injection or by mouth. Injections are given weekly or every 2 weeks.
Ivermectin should NOT be used in herding breeds, which include Collies, Border Collies, Shetland Sheepdogs, Australian Shepherds, or Old English Sheepdogs. Herding breeds can carry a gene known as MDR1, which makes them highly sensitive to Ivermectin. Many veterinarians agree that a better alternative for these dogs are the medications Selamectin or Milbemycin.
Treatment may also include antibiotics for any secondary bacterial infections. The dog’s environment, including bedding, collars, and harnesses, should also be thoroughly cleaned to kill any mites left behind.
The second type of mange affecting dogs is caused by the cigar-shaped mite Demodex canis, which are natural inhabitants of a dog’s skin. Under normal conditions, dogs live harmoniously with these mites and never experience any issues. However, if the dog’s immune system becomes suppressed, the mites can overgrow and cause mange.
Demodectic mange is the most common form of mange in dogs. It most often occurs in puppies and young dogs less than 18 months of age, since their immune systems are not fully developed. Demodectic mange is not contagious to other dogs, cats, or humans.
There are 3 types of demodectic mange, and all have their own symptoms:
Localized Demodectic Mange
This occurs when mites infest a few small areas of the body (usually the face) and results in scaly bald patches that resemble polka-dots. This form of mange is very common in puppies, and approximately 90% of cases resolve on their own with no treatment as the puppy’s immune system matures.
Generalized Demodectic Mange
The generalized form of demodectic mange usually results from a compromised immune system or endocrine problem, and involves large areas of the body. It may be hereditary. Secondary bacterial infections, which can cause foul odor and itching, are common with this form of mange.
This is the toughest, most resistant form of demodectic mange. It is found only on the feet and is accompanied by bacterial infection. Old English Sheepdogs and Shar-peis may be more prone to this form. Biopsies of the skin around the feet are often necessary to make a proper diagnosis.
Diagnosis of Demodectic Mange
Diagnosis of demodectic mange is the same as for sarcoptic mange – by skin scraping. It is usually easy to find Demodex mites by this method. Since the mites are naturally present in the body, it’s only when there are large numbers present in the sample that an overgrowth is suspected.
Treatment for Demodectic Mange
The treatment for demodectic mange depends on how severe it is. The localized form is usually left untreated (if the dog is a puppy) to allow the puppy’s immune system time to develop and clear the infection on its own. Topical antibacterial gel can be used to prevent secondary infection.
The generalized form requires more aggressive treatment. This can include prescription shampoo containing benzoyl peroxide, dips (usually Mitaban/Amitraz), oral medications such as Milbemycin, injectable meds such as Ivermectin, and antibiotics if bacterial infection is present. Since stress suppresses the immune system, it’s also important to create a comfortable, stress-free environment for the dog. Successful treatment for generalized demodectic mange may take many weeks to months, and require repeated treatments.
Dogs who experience even one bout of demodectic mange should not be bred due to the potential for passing the genes related to their weakened immune systems on to the next generation. If you have a puppy acquired from a breeder and the puppy is diagnosed with Demodex, be sure to let the breeder know.
Mange In Cats
Cats can also develop mange, although it is rare. The mite that causes mange in cats is Notoedres cati, and it causes intense itching of the face, ears, and neck, as well as hair loss and scabbing that can spread over the entire body. Notoedric mange is highly contagious to other cats.
Treatment for mange in cats is similar to treatment for sarcoptic mange in dogs. However, cats can be much more sensitive to toxic chemicals than dogs, so many vets avoid using chemical dips when treating cats with mange.
Mange is not only unsightly, it can be extremely uncomfortable and cause serious skin problems. No matter which treatment options are chosen, skin scrapings should be done every two weeks during treatment. After 2 consecutive skin scrapings are negative for mites, treatment can be discontinued.
It’s important to note that there are still outdated home treatments for mange being recommended on the internet. Some of these (such as dipping a pet in motor oil), are not only ineffective, they can be toxic. It’s best to thoroughly discuss all treatment options with your veterinarian and come up with a safe and effective treatment plan that is best for your dog or cat.
Has your dog or cat ever had mange? If so, how did you treat it? Please share your story with us in the comments below!