Rheumatic fever is a delayed immune response that can occur after certain group A streptococcal infections. It causes damage to certain organs, particularly the heart.

What is going on in the body?

Strep throat and scarlet fever are two types of infections that precede rheumatic fever. If a person is not treated effectively with antibiotics for these infections, he or she may have an immune response. The effects of this response can be seen in the heart, joints, brain, and skin. The most serious effect of rheumatic fever is a heart valve defect known as mitral valve prolapse. Rheumatic fever was more common before antibiotics were available to treat infections.

What are the causes and risks of the disease?

Rheumatic fever is an immune response to an infection with group A streptococcus. The same bacteria causes strep throat and scarlet fever. While streptococcal skin infections are fairly common, they have not been linked to rheumatic fever.

Rheumatic fever is most prevalent in school-age children who are 5 to 15 years old. It is seen most often in the cold winter months when strep throat is also most common. Rheumatic fever may also occur in adults. It is seen with equal frequency in men and women. However, women with rheumatic fever are more likely to develop Sydenham chorea and mitral valve prolapse.