A rheumatologist is a specialist physician who deals with the diagnosis and treatment of musculoskeletal and autoimmune disorders that are commonly known as rheumatic diseases. These diseases affect the joints, tendons, bones, muscles, and other connective tissues.

Some of the diseases that a rheumatologist treat are:
Osteoarthritis
Rheumatoid arthritis
Gout
Lupus
Spondyloarthropathies
Sjogren's syndrome
Chronic back pain
Scleroderma
Lyme disease
Infectious arthritis
Osteomyelitis
Juvenile idiopathic arthritis
Iritis
Osteoporosis
Reflex sympathetic dystrophy

Some of the symptoms for which you may need to see a rheumatologist are:
Unnexplained rash
Joint pain
Recurrent fever
Arthritis
Anaemia
Weakness
Fatigue
Muscle pain
Autoimmune disease
Loss of motion in joints
Anorexia

A rheumatologist and an orthopaedic doctor are not the same. Both rheumatologists and orthopaedics focus on diseases related to a persons muscles, joints, and bones. However, a rheumatologist treats these diseases with the use of medications and other non-surgical methods. An orthopaedist, on the other hand, specialises in surgical treatments and also, in managing fractures.

A rheumatologist is not qualified to treat bone cancer. A team of doctors may usually be involved in the treatment of bone cancer, which may include an orthopaedic surgeon, an orthopaedic oncologist, a radiation oncologist and a medical oncologist.