Rheumatic fever is an autoimmune disease that can develop as a result of a streptococcal throat infection. It causes inflammation of the heart, joints, brain, and skin. The disease is most common in children ages 5-15 in developing countries. It is diagnosed using the Modified Jones Criteria which looks for major criteria like heart inflammation, arthritis, subcutaneous nodules, and minor criteria like fever and joint pain along with evidence of a prior streptococcal infection. Treatment involves antibiotics to treat the infection as well as medications for symptoms while long term prevention relies on regular antibiotics.