Polymyositis in the Kooikerhondje: Causes, Symptoms & Care

The Kooikerhondje dog breed originates from the Netherlands, where they were historically duck tolling dogs known from paintings dating back to the 17th and 18th centuries. Though uncommon in the UK, they make devoted pets and working companions.

Kooikerhondjes are small dogs, part of the Kennel Club’s utility dog group. They are energetic yet manageable, highly intelligent, and respond well to training. Their low-shedding coat needs minimal grooming, and they can tolerate being alone for a few hours without distress.

This breed is known for being friendly, loving, sensitive, and family-oriented, making them excellent pets for homes with children. However, their sensitivity means they thrive with kind, consistent interaction and positive reinforcement.

While generally healthy with a lifespan of 12 to 15 years, Kooikerhondjes can be predisposed to certain hereditary health conditions, one of which is polymyositis — an immune-mediated muscle inflammation disorder.

What is Polymyositis in Kooikerhondjes?

Polymyositis is a genetic condition where the dog's immune system mistakenly attacks its own skeletal muscles, causing inflammation, pain, and muscle loss. It typically presents in adult dogs rather than puppies. The disease may progress slowly or appear suddenly with acute symptoms.

This condition results from a genetic predisposition involving a specific deletion near the IL21 and IL2 immune response genes. Dogs inheriting two copies of this deletion have a higher risk (10-20%) of developing polymyositis, while those with only one copy tend to have a much lower risk.

Why Are Kooikerhondjes at Risk?

The breed's relatively small gene pool in the UK makes hereditary conditions like polymyositis more prevalent in certain lines. Responsible breeders test for genetic markers to reduce the risk, helping to maintain the breed's health and longevity.

Recognising Symptoms at Home

• Muscle weakness and tremors
• Sudden or gradual weight loss despite a good appetite
• Lethargy, depression, or disinterest in play and exercise
• Lameness or difficulty moving on one or more legs
• Loss of muscle mass and tone
• Muscle pain or discomfort

How is Polymyositis Diagnosed?

Veterinarians diagnose polymyositis through a combination of elevated creatine kinase (CK) levels—indicating muscle damage—electromyograms (EMG), and muscle biopsies from specific muscles such as the triceps or femoral biceps. Early and accurate diagnosis is essential for effective management.

Treatment and Management

Treatment primarily involves immunosuppressive medications like oral steroids given over weeks to reduce inflammation and prevent further muscle damage. Physical therapy and nutritional support may also be prescribed to aid recovery and maintain muscle strength. Though some dogs may experience recurrent episodes, early recognition and prompt veterinary care can restore quality of life.

Preventing Polymyositis Through Responsible Breeding

Genetic testing for polymyositis predisposition is crucial for breeders to avoid mating two high-risk dogs. The Kooikerhondje community encourages regular health screening and sharing of genetic information to minimise cases of this debilitating disease.

Other Health Conditions to Know

Caring owners should also be aware that Kooikerhondjes are susceptible to other hereditary conditions, including Von Willebrand disease and Hereditary Necrotising Myelopathy. Routine health checks with your vet and ongoing breeder support help maintain your dog’s wellbeing.

Conclusion

Polymyositis is a significant health concern for Kooikerhondje dogs but with careful breeding, early detection, and ongoing veterinary care, owners can help their dogs live happy, active lives. Understanding this condition encourages responsible ownership and supports the health of this charming breed.