Polymyositis in Dogs
Polymyositis is a high-severity autoimmune condition that can affect dogs of all ages and breeds. Polymyositis is an immune-mediated inflammatory disease affecting skeletal muscles throughout the body, causing generalised weakness, muscle atrophy, and pain. It can be idiopathic or occur secondary to neoplasia or other immune-mediated diseases. It is documented across 4 breeds, though prevalence and severity can differ significantly between them. It typically becomes apparent at 5-10 years. Early signs to watch for include generalised muscle weakness, exercise intolerance, stiff gait, and muscle wasting. When treatment is required, costs are estimated at £800-£2,500/year depending on severity, location, and the specific intervention needed. This page covers symptoms, treatment options, and preventive steps — along with breed-specific information where available.
Signs & Symptoms
The following symptoms are commonly associated with Polymyositis in dogs. If your dog displays several of these signs, consult your vet promptly — early diagnosis typically leads to better outcomes.
- Generalised muscle weakness
- Exercise intolerance
- Stiff gait
- Muscle wasting
- Megaoesophagus (if oesophageal muscles involved)
- Dysphagia
Treatment Overview
Immunosuppressive therapy with prednisolone is the mainstay. Azathioprine is added for steroid-sparing effect. Underlying neoplasia must be ruled out and treated. Prognosis is variable.
Typical onset: 5-10 years
Prevention & Screening
While not all cases of Polymyositis can be prevented, the following steps reduce risk or enable earlier intervention:
- No proven prevention
- Exclude underlying neoplasia with thorough work-up
Estimated Treatment Cost
Treatment for Polymyositis is estimated at £800-£2,500/year, depending on severity, the specific intervention required, and your location. Costs may be higher for surgical procedures or ongoing management. Comprehensive pet insurance covering this condition is strongly recommended.
Breeds Affected by Polymyositis
The following 5 breeds are documented as being susceptible to Polymyositis. Click any breed to view breed-specific information about this condition, including prevalence and recommended screening.
Looking for more information? Browse all dog health conditions or explore the health guides for in-depth breed care advice.