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Masticatory Muscle Myositis in Dogs: Jaw Welfare

MMM is an immune-mediated inflammatory disease of the jaw muscles causing trismus and welfare impacts. This guide covers recognition and management.

Key Facts

MMM involves immune-mediated inflammation of the jaw-closing muscles
Affected dogs cannot open their mouth normally — trismus is the cardinal sign
German Shepherds, Dobermanns, and large breed dogs are most commonly affected
Acute phase presents with swollen, painful jaw muscles
Chronic phase causes muscle atrophy and jaw fixation through fibrosis
Early immunosuppressive treatment prevents permanent jaw restriction

Welfare Considerations and Management

Welfare-centred MMM management requires prompt diagnosis and immunosuppression. The 2M antibody test confirms the diagnosis. High-dose prednisolone is the cornerstone of treatment. Feeding soft food and using syringe feeding if needed maintains nutrition during the acute phase. Azathioprine or mycophenolate are added as steroid-sparing agents for long-term management. Physiotherapy with gentle jaw opening exercises prevents fibrosis in chronic cases.

What You Can Do

Seek prompt veterinary assessment for any dog unable to open its mouth normally
Begin high-dose immunosuppression early to prevent permanent jaw restriction
Feed soft food or use a syringe to maintain nutrition during treatment
Continue physiotherapy jaw exercises under veterinary guidance to prevent fibrosis