Dermatomysitis (DMS) is an autoimmune disease with a genetic background and additional environmental triggers. The disease is characterized by lesions of the skin on body-parts with minimal muscle overlay in affected Collies and Shetland Sheepdogs. While the onset of the disease is very variable, first symptoms might occur at about 12 weeks of age. Typical symptoms include hair loss and crusts in areas of legs and feet, the face and ears and the tail. In some cases, those symptoms weaken or disappear, sometimes even reappear during the life of a dog. In contrast to Shetland Sheepdogs, Collies often exhibit muscular dysfunctions like a high stepping gait, difficulties to swallow, drink and eat or muscle atrophy of the head and neck.