Rheumatic fever symptoms vary. You can have few symptoms or several, and symptoms can change during the course of the disease. The onset of rheumatic fever usually occurs about two to four weeks after a strep throat infection.

Rheumatic fever signs and symptoms — which result from inflammation in the heart, joints, skin or central nervous system — can include:

• Fever
• Painful and tender joints — most often in the knees, ankles, elbows and wrists
• Pain in one joint that migrates to another joint
• Red, hot or swollen joints
• Small, painless bumps (nodules) beneath the skin
• Chest pain
• Heart murmur
• Fatigue
• Flat or slightly raised, painless rash with a ragged edge (erythema marginatum)
• Jerky, uncontrollable body movements (Sydenham chorea, or St. Vitus' dance) — most often in the hands, feet and face
• Outbursts of unusual behavior, such as crying or inappropriate laughing, that accompanies Sydenham chorea

Rheumatic fever can occur after an infection of the throat with a bacterium called group A streptococcus. Group A streptococcus infections of the throat cause strep throat or, less commonly, scarlet fever. Group A streptococcus infections of the skin or other parts of the body rarely trigger rheumatic fever.

The link between strep infection and rheumatic fever isn't clear, but it appears that the bacterium tricks the immune system. The strep bacterium contains a protein similar to one found in certain tissues of the body. So immune system cells that would normally target the bacterium may treat the body's own tissues as if they were infectious agents — particularly tissues of the heart, joints, skin and central nervous system. This immune system reaction results in inflammation.

If your child receives prompt treatment with an antibiotic to eliminate strep bacteria and takes all medication as prescribed, there's little chance of developing rheumatic fever. If your child has one or more episodes of strep throat or scarlet fever that aren't treated or not treated completely, he or she might develop rheumatic fever.

Factors that can increase the risk of rheumatic fever include:

• Family history. Some people carry a gene or genes that might make them more likely to develop rheumatic fever.
• Type of strep bacteria. Certain strains of strep bacteria are more likely to contribute to rheumatic fever than are other strains.
• Environmental factors. A greater risk of rheumatic fever is associated with overcrowding, poor sanitation and other conditions that can easily result in the rapid transmission or multiple exposures to strep bacteria.

Inflammation caused by rheumatic fever can last a few weeks to several months. In some cases, the inflammation causes long-term complications.

Rheumatic heart disease is permanent damage to the heart caused by rheumatic fever. It usually occurs 10 to 20 years after the original illness. Problems are most common with the valve between the two left chambers of the heart (mitral valve), but the other valves can be affected. The damage can result in:

• Valve stenosis. This narrowing of the valve decreases blood flow.
• Valve regurgitation. This leak in the valve allows blood to flow in the wrong direction.
• Damage to heart muscle. The inflammation associated with rheumatic fever can weaken the heart muscle, affecting its ability to pump.

Damage to the mitral valve, other heart valves or other heart tissues can cause problems with the heart later in life. Resulting conditions can include:

• An irregular and chaotic beating of the upper chambers of the heart (atrial fibrillation)
• An inability of the heart to pump enough blood to the body (heart failure)