Rheumatic fever is an inflammatory disease that occurs following a streptococcal throat infection. It is believed to be caused by an autoimmune response where antibodies generated to fight the streptococcal infection cross-react with tissues in the heart, joints, skin, and brain. This causes inflammation and damage, particularly to the heart valves. If not properly treated, rheumatic fever can lead to chronic rheumatic heart disease where repeated valve damage and scarring occurs.