Rheumatic fever is an autoimmune condition that causes inflammation of the body’s tissues - notably the joints and heart. This inflammation occurs as an overreaction to an infection from the Group A streptococcus bacteria - the pathogen that causes strep throat and scarlet fever. When these conditions go untreated or incompletely treated (for instance, if a course of antibiotics goes unfinished), the infection may progress into rheumatic fever. The Group A streptococcus bacterium contains a protein similar to a protein found in the body’s tissue. Because of this, experts believe, the immune system mistakenly attacks healthy tissue instead of the infectious pathogen.

Rheumatic fever is most common in children between the ages of 5-15, corresponding with the ages when strep throat is most likely. This condition is rare in the United States but is common in developing countries. Symptoms vary depending on the severity of the infection.

Common symptoms include:

• Fever
• Pain, tenderness, and swelling in the joints (especially the knees, elbows, and ankles)
• Chest pain
• Irregular heart rhythms or heart murmurs
• Small bumps under the skin
• A flat or slightly raised rash with a ragged edge
• Jerky movements in the hands, feet, and face (Sydenham chorea)
• Persistent headaches

If your child begins to exhibit the signs and symptoms of strep throat, seek medical attention. Strep throat can be treated easily with a course of antibiotics. Early and complete treatment can prevent the condition from progressing to rheumatic fever.

If signs or symptoms of rheumatic fever are present (such as joint pain), seek medical attention immediately. The autoimmune response that causes rheumatic fever can cause permanent damage to the heart. This is known as rheumatic heart disease and can lead to abnormal heart rhythms or heart failure.