Rheumatic fever is a rare inflammatory illness that sometimes occurs in people after they have a group A streptococcal infection.
Rheumatic fever can occur in anyone who has a group A streptococcal infection.
There is no one specific laboratory test for the diagnosis of rheumatic fever. A streptococcus, or recent scarlet fever. The absence of supporting evidence of preceding streptococcal infection should make the diagnosis doubtful, except in rare cases.