Connective tissue disease refers to a group of disorders that affect the tissues supporting organs and other parts of the body. These diseases can impact the skin, joints, blood vessels, and internal organs. Common types include lupus, rheumatoid arthritis, and scleroderma. The exact cause of these diseases is often unknown, but they can involve an autoimmune response where the body mistakenly attacks its own tissues. Symptoms of connective tissue diseases vary widely but may include joint pain, fatigue, and skin rashes. Diagnosis typically involves a combination of physical examinations, blood tests, and imaging studies. Treatment often focuses on managing symptoms and may include medications, physical therapy, and lifestyle changes.