Rheumatology Rheumatology is the medical specialty concerned with the study, diagnosis and treatment of various conditions that include pain or other symptoms of bone, joints, and/or muscle (musculoskeletal system). Rheumatologists treat arthritis, certain autoimmune diseases, musculoskeletal pain disordered, and osteoporosis. There are more than 100 types of these diseases, including rheumatoid arthritis, osteoarthritis, gout, lupus, back pain, fibromyalgia, and tendonitis.