Systemic autoimmune diseases are conditions where the body's immune system mistakenly attacks its own tissues, leading to widespread inflammation and damage. These diseases can affect multiple organs and systems, causing a variety of symptoms that may vary from person to person. Common examples include lupus, rheumatoid arthritis, and scleroderma. The exact cause of systemic autoimmune diseases is not fully understood, but they are believed to result from a combination of genetic, environmental, and hormonal factors. Diagnosis often involves blood tests and clinical evaluations, while treatment typically focuses on managing symptoms and suppressing the immune response to prevent further damage.