Dermatomyositis in Dogs: Causes, Symptoms & Care
Dermatomyositis in dogs is a genetic and autoimmune inflammatory disorder affecting the skin, muscles, and blood vessels, primarily seen in specific breeds. It leads to painful skin lesions and muscle weakness, often noticed early in young dogs, particularly collies, Shetland sheepdogs, and Australian cattle dogs. Rough Collie puppies and Shetland Sheepdog puppies are especially predisposed to this condition.
Breeds Most at Risk of Dermatomyositis
This inherited condition mainly affects certain herding breeds, notably:
The disease appears to be inherited, usually showing signs within the first six months of life. Responsible breeders test for dermatomyositis to help reduce its occurrence.
Recognising Symptoms of Dermatomyositis
Dogs with dermatomyositis may exhibit a range of symptoms, including:
- Stiff, stilted gait and muscle weakness
- Muscle swelling and pain when touched
- Intolerance to exercise and general lethargy
- Skin lesions such as crusted sores and ulcers, especially on the face, ears, lips, and tail
- Enlargement of the oesophagus (megaesophagus) causing regurgitation and risk of aspiration
- Swollen oesophagus leading to difficulty swallowing
Dogs may develop hair loss, footpad ulcers, nail abnormalities, and may suffer from muscle atrophy affecting facial muscles and jaw strength.
Causes and Underlying Factors
Dermatomyositis in dogs is primarily an autoimmune disease with a hereditary basis. It involves the immune system mistakenly attacking the body's own muscle and skin tissues.
Other contributing factors can include:
- Immune-mediated responses triggered by infections or cancer
- Reactions to certain medications
Environmental stressors, vaccinations, or infections may exacerbate the disease in predisposed dogs.
Diagnosis: How Vets Confirm Dermatomyositis
Veterinarians require a detailed history and a thorough physical examination. Diagnosis may involve several tests to assess muscle and skin health, including:
- Complete blood count and biochemistry profile
- Urinalysis
- Creatine kinase enzyme levels to detect muscle damage
- X-rays to check for oesophageal enlargement or tumours
- Skin and muscle biopsies for definitive diagnosis
Early and accurate diagnosis improves management and outcomes.
Treatment Options for Dermatomyositis
Treatment focuses on suppressing the immune system and managing symptoms:
- Immunosuppressive drugs such as corticosteroids
- Antibiotics if secondary infections are present (complete the course as prescribed)
- Supportive care for oesophageal issues, including specialised feeding techniques
- Physical therapy and gradual exercise to strengthen muscles as inflammation reduces
Living with a Dog Diagnosed with Dermatomyositis
With good veterinary care, many dogs respond well to treatment. Owners might need to adapt feeding methods for dogs with megasophagus, including hand-feeding or feeding from an elevated position to reduce the risk of regurgitation.
Skin lesions require ongoing management to prevent infection and discomfort. Regular veterinary check-ups and supportive care are crucial for quality of life.
Prognosis: What to Expect
The outlook varies depending on underlying causes:
- Dogs with immune-mediated dermatomyositis often have a positive prognosis with proper treatment
- Prognosis is more guarded if the condition is linked to cancer or severe immune disorders
Early detection and responsible breeding significantly improve chances for affected breeds.
What is Dermatomyositis in Dogs?
Quick Answer: Dermatomyositis is an inherited autoimmune disease causing inflammation and lesions on the skin and muscles of certain dog breeds, including Rough Collies and Shetland Sheepdogs.
Dermatomyositis causes painful symptoms such as skin sores, muscle weakness, and difficulty moving or swallowing. It is a lifelong condition requiring veterinary diagnosis and ongoing management to ensure the best possible quality of life. Responsible breeders screen for this disorder to reduce its prevalence in at-risk breeds.
