Acute rheumatic fever is the most common cause of acquired heart disease in children, especially in poor, overcrowded communities. It is a complication of pharyngitis (a throat infection) caused by Streptococcus bacteria. An unusual immune response by the body to this bacterial infection damages the joints, heart and other tissues of the body. The exact mechanism whereby this happens is still not fully understood. Acute rheumatic fever is usually seen in children aged 5 to 15 years.
Many strains of Group A beta haemolytic Streptococcus can cause rheumatic fever which is a multisystem disease affecting the heart, joints, skin and brain. Recent studies suggest that skin infections (impetigo) may also cause rheumatic fever.
Rheumatic fever is the most common cause of acquired heart disease in children in developing countries.