M33: Dermatopolymyositis

Dermatopolymyositis, represented by the ICD-10 group code M33, refers to a group of conditions often classified under idiopathic inflammatory myopathies — diseases characterized by inflammation and weakness of the muscles. These conditions can affect people of any age but tend to be common in children and in adults in their late 40s to early 60s. While the exact cause of these diseases is unclear, they could potentially involve immune system activity against the body's own tissues, possibly triggered by environmental factors in individuals with certain genetic backgrounds. Symptoms typically include muscle weakness, often in the areas closest to the center of the body, such as shoulders and thighs. Over time, this weakness can progressively worsen, making daily activities challenging. A distinct feature of this group is the simultaneous occurrence of skin rashes, with areas of redness and inflammation primarily on the face, knuckles, neck, shoulders, upper chest, and back. Both the muscle and skin involvement have implications on the person's mobility and quality of life.