Demodectic mange is a parasitic skin disease in dogs caused by mites. It is one of the most common forms of mange found in dogs.
Sometimes, demodectic mange is called “red mange” (due to its red, yet relatively painless appearance) or “demodex.”
This particular type of mange is caused by a mite that lives deep in your dog’s hair follicle. Though this mite is similar to sarcoptes scabei, they are not one and the same.
The sarcoptes scabei is a small mite that lives beneath the skin’s surface. Sarcoptes scabei mites are light-colored and oval-shaped, as well as microscopic. They can also be transmitted from host to host, and are often referred to as canine scabies.
Because this is not the same type of mite that causes demodex, the causes and treatments will be very different.
About Demodectic Mites
There are a couple of different forms of the demodex mite. There is a mite that lives on cats, and a mite that lives on humans. The type of mite that lives on dogs is called the demodex canis.
This particular mite is thin, long, and shaped a bit like a cigar. As adults, they have eight legs, and live inside the hair follicle. These mites are so tiny, several of them can live inside one hair follicle. Sometimes they are so tiny and hidden so well, even using a microscope they can be hard to find.
Lifecycle of Demodectic Mites
This type of mite spends pretty much its entire life burrowing around in your dog’s hair follicle. The females will lay their eggs and the eggs will hatch. The entire life cycle from larvae to adult is thought to last 20 to 35 days.
Because the demodectic mite is so common, most dogs carry them in a small number, even when they are perfectly healthy. It’s only when your dog develops a compromised immune system that the mites can get out of control and cause a larger problem. Sometimes (although not always) this type of mite can trigger itching.
When it does itch, your dog may scratch until they break open the skin causing a secondary bacterial infection, which causes more itching, along with the unsightly balding, redness, and oozing that is often associated with demodex.
Dogs Most at Risk for Demodectic Mange
Demodex mange is sometimes called “puppy mange,” because it is more prevalent in pups than grown dogs. This type of mange is related to a suppressed immune system, whether that’s due to stress or illness.
Some dog breeds are more prone to developing demodex mange than others, including the:
- American Pit Bull Terrier
- English Bulldog
- Boston Terrier
- Afghan Hound
- Chow Chow
- Doberman Pinscher
- German Shepherd
- Great Dane
These and several more are all breeds that have a genetic tendency to develop demodectic mange. Since it seems to be an inherited trait, dogs that suffer from this condition or dogs that have family members that suffer from this condition should not be bred.
Transmission of Demodectic Mites
Demodectic mite transmission is via direct contact. This occurs in the first week of life between a mother and her pup. Pretty much every mama dog possesses these mites, and passes these mites on to her pups. Some dogs will be immune, and others will not.
However, this type of mite is not contagious and cannot be passed on to humans or from host to host, only between mother and child. This type of mite also doesn’t spread into bedding, or require any special cleaning or treatment of the home.
Causes of Demodectic Mange in Dogs
The primary “cause” of demodectic mange in dogs, if you can call it that, is a poor immune system. Dogs can suffer from a suppressed immune system for a variety of reasons and underlying health concerns, including
- Heartworms and intestinal worms
- Cushing’s disease
- A dog in heat
- Nursing pups
- And dogs that are on steroids
Unfortunately, because all dogs carry this mite and it’s passed on from mother to pup, virtually any dog can develop demodectic mange. Especially any dog whose immune system is subpar.
3 Types of Demodectic Mange
Dogs can suffer from three different types of demodex mange.
Localized Demodectic Mange
This is when the demodex mites multiply in a small, contained area. This often presents as little bald patches on your dog’s face. It’s considered common in puppyhood, and usually resolves on its own without requiring any treatment.
Generalized Demodectic Mange
This can type of demodex can affect large patches of your dog’s body. This type will develop as a result of a floundering immune system in older dogs, and may point to an underlying health issue. Generalized demodectic mange creates a ripe environment for an accompanying bacterial infection, and can become very itchy and smelly. Treatment options will vary depending on your dog’s age.
This type of demodex mange is the most resistant to treatment. It affects the foot and is usually coupled with a bacterial infection. Unfortunately, these mites can be very difficult to locate, making a deep biopsy a requirement for proper diagnosis and treatment.
Symptoms of Demodectic Mange in Dogs
With demodex, your dog may experience hair loss and quite a bit of balding, as well as develop sores and scabbing.
Because secondary bacterial infections are common with this type of mange, your dog can also suffer from itchy skin and all the associated discomforts that come with it.
Demodex mange can cause lesions characterized by crusty red skin, and sometimes your dog may look moist or greasy. The lesions may ooze a clear, somewhat oily liquid, which is what gives them the greasy look.
These particular symptoms are seen only in generalized demodex, however. This is because the whole body is involved with generalized demodectic mange. The balding and hair loss can cover your dog’s entire body, including the along the abdomen, the back, the legs, head, and feet.
Other symptoms of demodex mange include:
- Elephant skin
- Acne-like bumps
- Increased itching at night
- Swollen lymph nodes
Localized mange tends to be much less serious and is usually only seen around the head and muzzle area in puppies, usually in small little patches, and will often go away on its own.
Diagnosing Demodectic Mange
Most of the time your dog will be diagnosed by taking skin scrapings and analyzing them under a microscope. Sometimes your vet may opt to pluck hairs also to examine the hair follicle.
In some cases, a biopsy may be needed. No matter the method used for diagnosis, the mites must be present with skin lesions for the diagnosis to be accurate. The presence of mites alone does not prove demodectic mange.
It’s also important to properly diagnose your dog, because in some cases, if your dog is diagnosed with the wrong problem, the treatment options that may be given can actually make demodectic mange worse.
Older dogs that are diagnosed with demodex should also be evaluated for underlying diseases that may be taxing their immune system, and then be treated for those as well.
Your vet may ask you for your dog’s health and nutrition history, and whether or not they’ve ever been on any corticosteroids or other immune-suppressing drugs.
Treating Demodectic Mange in Dogs
As stated before, localized demodectic mange is extremely common, and usually resolves all on its own.
When it comes to generalized demodectic mange, however, treatment can get a bit more in-depth. It can also become expensive and get a little confusing at times. Sometimes topical medications may be necessary, and even oral medications or special dips and shampoos.
If your dog is suffering from secondary bacterial infection, they may require a round of antibiotics as well. However, it’s important to be careful in properly diagnosing the condition and giving your dog the proper treatment they need.
If there isn’t really a secondary bacterial infection and you give your dog antibiotics, those medications can compromise your dog’s immune system further, and compound the mange problem. The same goes for giving your dog steroid medications. They weaken the immune system and in many cases, can make things worse.
You must be careful as some dogs can have a reaction to the dips and be very sensitive to them. In those cases, you’ll need to dilute them and use them at half-strength.
Sometimes dogs don’t respond to the dips at all, and may require additional oral medications such as Ivermectin and Milbemycin Oxime. These drugs should only be administered under the care of your vet, and your dog needs to be closely monitored for any adverse reactions.
Living with Demodectic Mange
Dogs that suffer from demodectic mange should follow up with their vet on a regular basis and receive regular skin scrapings to make sure the treatment path is working, and to make sure the mite population is not continuing to grow.
Though demodectic mange is not inherited, the conditions that suppress your dog’s immune system can be, and this is what may make him vulnerable to demodectic mange.
This is why there is an argument to be made that dogs that have a family history with this type of mange should not be bred.
However, it’s a pretty hotly debated topic, and one that will most likely continue to be debated for a long time to come. Those who oppose this view question whether or not this theory is accurate, because generalized demodex has not be clearly shown to be inherited.
Another opposition to this view is the question of why there are some cases where the disease only shows up in one dog within its generational line. If it was a genetic disorder, it should show up elsewhere in the dog’s family tree, not just as one or two isolated cases. Siblings would get it, yet there are many cases where one pup will contract the disease and the rest of the litter will not.
Despite the arguments, what can’t be argued is that it does seem to occur more often in certain breeds over others, and that it is brought on by a weakened immune system, often related to an underlying health condition.
This doesn’t necessarily mean that demodex mange is genetic, but it can mean that certain breeds are predisposed to a weaker immune system, which can then make them more susceptible to demodectic mange. This seems to be the most likely theory at this point.
Plus, the fact that this type of mange is most prevalent in puppies supports this theory, because puppies are born with immune systems that are weak and still developing. So, it makes sense that they are more vulnerable. And when you weigh the fact that not all puppies in a litter may contract demodex mange, it lends even more credence to the idea that a dog’s immune system plays a large role in whether a dog will develop this condition.
Also, an interesting factoid about demodex is that most dogs that contract demodex mange also often suffer from yeast infections. The two health issues tend to go hand-in-hand.
Yeast infections have long been shown to be related to gut health. And gut health has long been shown to tie back to immune health.