Dermatomyositis (DMS)

Dermatomyositis (DMS) is an autoimmune inflammatory disease that affects a dog’s skin and muscles. This disease is typically diagnosed in Collies and Shetland Sheepdogs and is thought to be caused by a combination of genetic and environmental factors. Skin lesions can present anywhere from 3-6 months of age and can consist of hair loss and skin crusts on areas such as the face, ear tips, legs, feet, the tip of the tail, or any other bony prominences. The lesions begin as areas of swelling that become ulcers and develop into crusty hairless regions. The disease has been seen to peak around 1 year of age and may improve over time. A definitive diagnosis of DMS can be made with a skin biopsy and potential treatment options do exist to minimize symptoms. Some dogs with DMS may develop muscle inflammation leading to muscle atrophy. Although most dogs will respond to treatment, relapses can be common with lesions eventually resulting in scarring. Mutations in three different genes have been identified that combined provide an associated risk level for the development of DMS as detailed in the chart below under result explanations.  Resources for DMS breeding probabilities and additional information can be found at:

https://www.colliehealth.org/collie-health-101/dermatomyositis/

https://www.americanshetlandsheepdogassociation.org/dermatomyositis/

Additional Details

Publication:

Evans JM, Noorai RE, Tsai KL, Starr-Moss AN, Hill CM, Anderson KJ, Famula TR, Clark LA. Beyond the MHC: A canine model of dermatomyositis shows a complex pattern of genetic risk involving novel loci. PLOS Genetics. 2017 Feb 3; 12(2) [PubMed: 28158183]