Rheumatoid arthritis is mostly related to streptococcal infections and needs to be differentiated from internal rheumatoid arthritis, ankylosing spondylitis, and other joint pains caused by autoimmune diseases. The main characteristic of rheumatoid arthritis is symmetrical pain in the joints of both hands, usually affecting multiple joints and accompanied by morning stiffness, and even systemic symptoms such as mild fever. The main features of ankylosing spondylitis are stiffness in the neck or pain in the lower back, with pain worsening after rest and alleviating after activity. Diagnosis requires a combination of CT of the sacroiliac joints and tests such as HLA-B27. Joint pain caused by other autoimmune diseases, such as systemic lupus erythematosus, often presents clinically with facial rashes, accompanied by hair loss, recurrent oral ulcers, and even Raynaud's phenomenon and mild fever. Diagnosis requires comprehensive tests including complete blood count, erythrocyte sedimentation rate, autoimmune antibodies, abnormal immunoglobulins, etc., based on the corresponding clinical manifestations and tests, to provide differential diagnosis.