Masticatory muscle myositis affects a dog’s ability to chew. The condition is painful and generally accompanied by swollen muscles used for chewing. MMM may be accompanied by protruding or bulging eyes known as extraocular myositis. Early diagnosis and treatment are important for complete recovery.

Masticatory Muscle Myositis Is More Common in Large Dogs

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Large dogs — especially German Shepherds, Retrievers, and Doberman’s — are more likely to have MMM. Cavalier King Charles Spaniels may be genetically inclined to acquire the condition. However, smaller dogs are not immune, and symptoms of MMM in any dog should be taken seriously. Males and female dogs are equally likely to be affected.

The exact cause of MMM is not known, but it is thought to be an immune-related disorder — the immune system normally protects animals from infection, but sometimes attacks body systems.

Specific Symptoms of Masticatory Muscle Myositis

MMM may develop slowly or suddenly. Symptoms include drooling, swelling of jaw muscles on one or both sides — usually both —, fever, difficulty eating, and inability to close the mouth — trismus. The symptoms may result in an overall change in a dog’s personality due to discomfort. Humans who have suffered from severe TMJ — temporomandibular disorder — have a pain of a type and location of dogs suffering from MMM.

Owners can perform an initial examination by gently feeling the muscles behind the mouth to try to detect swelling. Dogs may react to the examination by resisting due to pain. The swelling can be visible depending on the breed of dog, the severity of the condition, and the amount of hair present.

MMM may occur in conjunction with extraocular myositis — protruding eyeballs — and is diagnosed and treated similarly.

Specific Symptoms of Masticatory Muscle Myositis

Specific Symptoms of Masticatory Muscle Myositis

Treatment of Masticatory Muscle Myositis

MMM sometimes clears up without treatment, but dogs are subject to recurrence of the disease. Untreated or frequent occurrences, however, can result in serious damage to the muscles involved. A veterinarian should be involved in diagnosis and treatment. Diagnosis may require blood work to isolate the condition. There are other causes for swollen jaws.

Treatment generally involves the use of corticosteroid drugs like prednisone. Treatment may last several months in order to prevent recurrence.

Recovery rates are good, although the condition may come back and require another round of drugs. Early diagnosis and treatment are important. Waiting too long can result is a chronic condition in which the muscles atrophy — degenerate or shrivel permanently.

Masticatory muscle myositis — MMM — is an auto-immune disorder that affects a dog’s ability to chew. The muscles involved become swollen and painful. Complete recovery is enhanced by early diagnosis and treatment by a veterinarian. The most recommended treatment is the administration of corticosteroid drugs like prednisone.

Treatment of Masticatory Muscle Myositis

Treatment of Masticatory Muscle Myositis