Rheumatic fever is an inflammatory disease that can develop when strep throat or scarlet fever isn't properly treated. Strep throat and scarlet fever are caused by an infection with streptococcus (strep-toe-KOK-us) bacteria.
Rheumatic fever most often affects children who are between 5 and 15 years old, though it can develop in younger children and adults. Although strep throat is common, rheumatic fever is rare in the United States and other developed countries. However, rheumatic fever remains common in many developing nations.
Rheumatic fever can cause permanent damage to the heart, including damaged heart valves and heart failure. Treatments can reduce damage from inflammation, lessen pain and other symptoms, and prevent the recurrence of rheumatic fever.
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:
- 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 beneath the skin
- Chest pain
- Heart murmur
- Flat or slightly raised, painless rash with a ragged edge
- Jerky, uncontrollable body movements (Sydenham chorea) — most often in the hands, feet and face
- Outbursts of unusual behavior, such as crying or inappropriate laughing, that accompanies Sydenham chorea
When to see a doctor
Have your child see a doctor for signs or symptoms of strep throat, which include:
- Sore throat that comes on suddenly
- Pain when swallowing
- Stomach pain, nausea and vomiting
Proper treatment of strep throat can prevent rheumatic fever. Also, have your child see a doctor if he or she shows other indications of rheumatic fever.
Rheumatic fever can occur after a throat infection from a bacteria 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 bacteria trick the immune system.
The strep bacteria contain a protein similar to one found in certain tissues of the body. The body's immune system, which normally targets infection-causing bacteria, attacks its own tissue, particularly tissues of the heart, joints, skin and central nervous system. This immune system reaction results in swelling of the tissues (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 aren't 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 fever can cause permanent damage to the heart (rheumatic heart disease). It usually occurs 10 to 20 years after the original illness, but severe cases of rheumatic fever can cause damage to the heart valves while your child still has symptoms. 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:
- Narrowing of the valve. This decreases blood flow.
- Leak in the valve. A leaky valve causes 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 heartbeat (atrial fibrillation)
- Heart failure
The only way to prevent rheumatic fever is to treat strep throat infections or scarlet fever promptly with a full course of appropriate antibiotics.