Dog Dermatomyositis Welfare and Management

Dermatomyositis is an inherited inflammatory disease of skin and muscle affecting Collies and Shetland Sheepdogs, causing disfiguring skin lesions, muscle wasting, and difficulty eating.

Key Facts

Dermatomyositis is autosomal dominant with variable expression in Rough Collies and Shelties
Skin lesions typically appear at 3-6 months of age on the face, ear tips, and bony prominences
Muscle atrophy — particularly of the temporalis muscles — causes a hollowed appearance and difficulty chewing
Megaesophagus can develop, causing regurgitation and aspiration pneumonia risk
Severity ranges from cosmetically mild to severely debilitating across affected individuals
Sun exposure worsens skin lesions; UV protection is a core management strategy
A genetic test exists to identify carriers, enabling responsible breeding decisions

Welfare Considerations

Dogs with moderate to severe dermatomyositis experience chronic pain from skin ulceration, difficulty eating due to muscle weakness, and — in severe cases — life-threatening aspiration pneumonia from megaesophagus. The progressive nature of the disease means welfare challenges accumulate over the animal's life. Management includes immunosuppressive therapy, nutritional support for muscle mass maintenance, and sun avoidance. For dogs with megaesophagus, upright feeding and specialized food consistency reduce aspiration risk. Breeding decisions have the greatest welfare impact: genetic testing can eliminate the disease from breeding lines over generations.

What You Can Do

Support breed clubs that require genetic testing before breeding Rough Collies and Shelties
Ask breeders about dermatomyositis genetic test results before purchasing puppies
Work with a veterinary dermatologist for management of affected dogs
Use sun-protective clothing and limit UV exposure for dogs with skin involvement
Consider adoption from rescue organizations if affected dogs are surrendered