Rheumatoid arthritis is an autoimmune disease that leads to chronic joint pain. It typically affects the small joints in a symmetrical pattern and is associated with inflammation of the joints. When uncontrolled, this can lead to joint erosions, deformities, and chronic disability. The diagnosis is made by a combination of clinical signs, laboratory data, and imaging findings. Early diagnosis is important since treatment with disease-modifying antirheumatic drugs (DMARD) can halt the progression of damage to the joints. Methotrexate is often used for initial treatment, but in refractory or progressive disease, then biologic DMARD therapies are initiated.