Most common manifestation of rheumatic fever –
Arthritis in RF 

It is the most frequent major manifestation (75% of cases).
It is migratory polyarthritis, i.e., several joints are involved in quick succession and each for a brief period of time.
Any joint may be affected but involvement of large joints such as knee, anlde, elbow, and wrist is common.
Small joints of hands and feet are not involved.
Inflammation of any one joint subside spontaneously within a week and the entire bout of polyarthritis rarely last more than 4 weeks.
Resolution is complete with no residual joint damage.
A striking feature is dramatic response to salicylates.
Arthritis
Carditis
Chorea
Nodules