Rheumatic fever and rheumatoid arthritis are two completely different diseases, but both are rheumatic in nature. Rheumatic fever is primarily a disease closely related to streptococcal infections, and its main symptom lies in the heart, which means that severe carditis can occur. Arthritis, chorea, and skin lesions, such as erythema annulare and subcutaneous nodules, may also occur, as well as fever. Arthritis due to rheumatic fever usually starts acutely and is only a temporary lesion. Its severity is far less than that of the heart, and there will be wandering redness, swelling, heat, and pain in the large joints, and joint function can usually be fully restored after effective treatment. Unlike rheumatoid arthritis, which is a chronic autoimmune disease, rheumatoid arthritis is mainly in the joints, and eventually leads to disability or dysfunction of the joints. It is usually characterized by symmetrical and multiple joint swelling, pain, and limitation of movement, so there is a big difference between the two.