MMM in Dogs
The most critical warning sign to watch for is your dog suddenly unable to open their mouth

MMM in dogs, also known as Masticatory muscle myositis is an extremely frustrating condition for your pet, as well as a very serious threat.

It can cause your dog’s head muscles to shrink as well as causing excessive salivation.


But that is only the minor problems it causes. It can become so painful to your dog that they cannot open their mouth normally, or in some cases, they will just quite trying because of the pain.

It is severe enough; it will also cause your dog’s eye to bulge. But the real danger starts with the complete loss of nutrients that may follow as the result of their inability to chew or eat.

MMM in dogs is an especially dangerous condition where your pets own immune system attacks itself.

As a result, causes inflammation of the mastication or chewing muscles.

Dogs mysterious eyesThe only chance with MMM in dogs is to control the immune system

It is very unique in that it attacks specific muscle fibers that are not found anywhere else in your dog’s body and it is very effective in this attack.

It is so effective, that the inflammation destroys the cells totally.

This disease can affect any dog at any age, but it does seem to have a preference.

It seems to attack young and middle aged German shepherds, Doberman pinchers, as well as all Retrievers.

This includes Labrador, Golden, Chesapeake Bay, and Flat-coat.

The muscles that are attacked in this vicious self-destruction include the cheek muscles, the temporal muscles, which are on top of your dog’s head, as well as what is known as the pterygoid muscles.

These muscles are extremely unique in your dog as they are found nowhere else in their body, and they consist of two parts that operate every aspect of the chewing process in your dog.

These muscles close your dog’s jaw, open it, as well as elevating it and pulling it forward.

They are also made up a unique fiber and it for this reason that is believed to be the cause of the bodies attack against itself.

Your dog’s body naturally releases antibodies to fight anything that it believed to be invading the body, and when an auto-immune response does occur, it actually attacks itself.

Because of the uniqueness of these muscle fibers, for whatever reason in these particular breeds, their system does not identify them properly, and the vicious attack starts.

MMM in dogs can occur in two different forms; acute of chronic.

The chronic form of this disease is the most common, and when this occurs your dog has a very difficult time in opening their mouth in a normal fashion.

In some cases, they may not be able to open it at all.

Although this form of the disease is extremely frustrating to both the dog as well as the owner, it does not cause your dog a lot of pain.

They just simply cannot open their mouth.


This form may also cause what is called atrophy in your dog’s head muscles.

This is medically described as a wasting or decrease in the size of a body organ or tissue. In this case, it is your dog’s head.

This usually causes a rather pointy appearance in your dog’s head that will also cause their eyes to appear sunken.

But despite this appearance, it is not dangerous, as they are still very alert and active; they just cannot open their mouths.

If this condition is acute, it has now suddenly become much more severe.

In the acute stage, your dog may develop a fever, excessive salivation that may lead to infections, and they will not let you touch their head as it has become very painful to touch.

Because of this pain, they will not want to eat anything and this is where the real danger comes in.

The symptoms of MMM in dogs will all depend on which form it is.

With the chronic form, your dog will generally only show two symptoms: the loss of ability to open their mouth normally as well as shrinkage in their head muscles.

However, once the head muscles do shrink, you may see a slight bulging of their eyes. If they have the acute form, the symptoms will be much more severe.

They will develop a very high fever that is usually accompanied by a swelling of the localized lymph nodes. This will than cause a swelling in their facial and forehead muscles.

Once this occurs, their eyes will actually start to bulge rather than appear sunken.

This may also trigger a protrusion of their third eyelid, which is both painful as well as a nuisance to your dog.

This is where they also start to salivate excessively as it becoming extremely painful to open their mouth. Because of this, they will not want to chew or eat anything at all.


MMM in dogs has several similar diseases, with the most common being a tooth abscess or oral ulcers.

Locked jaw is also very similar, but MMM does not result in the jaw locking; it just does not work properly.

Polymyositis, also referred to as PM, is also very similar, except it will affect several muscles in your dog’s body, while MMM only affects the jaws.

There is also a neuropathy condition that can affect your dog where the jaw actually drops and your pet can not close their mouth.

But again it is different because with MMM in dogs they cannot open their mouth.

Finally there is an infectious form of myositis, but it also affects several different muscles. With MMM, it is isolated specifically to these one sets of muscles.


Once MMM in dogs are properly diagnosed, the treatment is geared toward inhibiting the immune system form attacking itself in both forms.

The goal will be to slow down or mediate the antibodies destruction against itself. Prednisone, which is a corticosteroid, is usually very effective.

However, there are some cases where this will not work, and other steroid therapies may have to be used.

If the steroids are not immediately effective, your dog may have to be placed on a feeding tube to get nutrients back into their body as quickly as possible.

This sounds quite drastic, but there are several very effective and relatively painless ways to do this, including a small tube placed in your dog’s nose.

This is not that painful and produces very good results.

MMM in dogs can be very painful for your pet, and once you identify the symptoms, the sooner you can get them treated the faster they will recover.


However, with any type of steroid treatment, there is always the possibility of side effects.

Infections are the most common, and if you see any difficulty in urination or blood in your dog’s urine, you will need to notify your veterinarian.

You dog will also drink an excessive amount of water, and they may also pant more than normal.

But in most all cases, once treated, your dog will be able to open their mouth again and return back to normal.

Pet Medications for MMM in Dogs

Dog Vitamin Store

Copper Storage Disease in Dogs