Dermatomyositis is a medium-severity dermatological condition that can affect dogs of all ages and breeds. Dermatomyositis is an inherited inflammatory condition affecting the skin and muscles. It begins with skin lesions on pressure points and the face in young dogs and can progress to generalised skin disease and muscle atrophy causing difficulty eating and walking. It is documented across 3 breeds, though prevalence and severity can differ significantly between them. It typically becomes apparent at Under 6 months. Early signs to watch for include skin lesions on face, ears, and legs, muscle wasting, especially of masseters, difficulty eating in severe cases, and scarring and pigmentation changes. When treatment is required, costs are estimated at £400-£2,000/year depending on severity, location, and the specific intervention needed. Dermatomyositis has a hereditary component, so health-screening certificates from the breeder are strongly recommended for predisposed breeds. 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 Dermatomyositis in dogs. If your dog displays several of these signs, consult your vet promptly — early diagnosis typically leads to better outcomes.

• Skin lesions on face, ears, and legs
• Muscle wasting, especially of masseters
• Difficulty eating in severe cases
• Scarring and pigmentation changes
• Megaoesophagus in some cases

Treatment Overview

Mild cases may be managed with omega-3 fatty acids, vitamin E, and sun avoidance. Severe cases require pentoxifylline, tetracycline-niacinamide, or immunosuppressants. The condition is lifelong.

Typical onset: Under 6 months

Prevention & Screening

While not all cases of Dermatomyositis can be prevented, the following steps reduce risk or enable earlier intervention:

• Do not breed affected dogs
• Genetic testing available for Collies

Breeds Affected by Dermatomyositis

The following 2 breeds are documented as being susceptible to Dermatomyositis. Click any breed to view breed-specific information about this condition, including prevalence and recommended screening.

• Rough Collie (large)
• Shetland Sheepdog (small)