Rheumatologists specialize in the diagnosis and treatment of rheumatic diseases, which are musculoskeletal and systemic autoimmune diseases that typically cause pain, swelling and disfigurement in joints, according to the American College of Rheumatology. Specific diseases rheumatologists treat include lupus, osteoarthritis, rheumatic arthritis, tendinitis and gout.
Rheumatic diseases are chronic diseases that can cause permanent joint damage if left untreated, explains the American College of Rheumatology. A primary physician may refer a patient to a rheumatologist when muscle or joint pain does not resolve as expected or when a patient has a family history of the disease. Rheumatologists differ from orthopedists, who also treat joint disease, in that they do not perform surgery.