Rheumatoid arthritis is an allergic disease and one of the main manifestations of rheumatic fever. It usually starts with acute fever and joint pain, and the typical manifestations are mild or moderate fever, migratory polyarthritis, and the affected joints are mostly large joints such as knees, ankles, shoulders, elbows, and wrists. It is common to transfer from one joint to another. The lesions are red, swollen, burning, and painful. Some patients also have several joints that are affected at the same time. Atypical patients only have joint pain without other inflammatory manifestations. Acute inflammation generally subsides in 2-4 weeks without leaving sequelae, but it often recurs. If rheumatic activity affects the heart, myocarditis may occur, and even residual heart valve disease may be left.