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:

• 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 beneath the skin
• Chest pain
• Heart murmur
• Fatigue
• 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
• Fever
• Headache
• 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.

Although there's no single test for rheumatic fever, diagnosis is based on medical history, a physical exam and certain test results. Tests might include:

• Blood tests. Your doctor is likely to check for inflammation by measuring inflammatory markers in your child's blood, which include C-reactive protein and the erythrocyte sedimentation rate.

  Sometimes, a blood test that can detect antibodies to the strep bacteria in the blood is done. The actual bacteria might no longer be detectable in your child's throat tissues or blood.

• Electrocardiogram (ECG or EKG). This test records electrical signals as they travel through your child's heart. The results can tell if the electrical activity of the heart is abnormal and can help your doctor determine if parts of the heart may be enlarged.
• Echocardiogram. Sound waves are used to create pictures of the heart in motion, which can help your doctor to detect heart problems.

The goals of treatment for rheumatic fever are to destroy remaining group A streptococcal bacteria, relieve symptoms, control inflammation and prevent the condition from returning.

Treatments include:

• Antibiotics. Your child's doctor will prescribe penicillin or another antibiotic to eliminate remaining strep bacteria.

  After your child has completed the full antibiotic treatment, your doctor will begin another course of antibiotics to prevent recurrence of rheumatic fever. Preventive treatment will likely continue through age 21 or until your child completes a minimum five-year course of treatment, whichever is longer.

  People who have had heart inflammation during rheumatic fever might be advised to continue preventive antibiotic treatment for 10 years or longer.

• Anti-inflammatory treatment. Your doctor will prescribe a pain reliever, such as aspirin or naproxen (Naprosyn, Naprelan, Anaprox DS), to reduce inflammation, fever and pain. If symptoms are severe or your child isn't responding to the anti-inflammatory drugs, your doctor might prescribe a corticosteroid.
• Anticonvulsant medications. For severe involuntary movements caused by Sydenham chorea, your doctor might prescribe antiseizure medications, such as valproic acid or carbamazepine (Carbatrol, Tegretol, others).

Long-term care

Discuss with your doctor what type of follow-up and long-term care your child will need.

Heart damage from rheumatic fever might not show up for years. As an adult, your child will need to be sure doctors know about the rheumatic fever and get regular heart exams.

Your doctor might recommend bed rest for your child and ask you to restrict his or her activities until inflammation, pain and other symptoms have improved. If inflammation is in heart tissues, your child might need strict bed rest for a few weeks to a few months, depending on the degree of inflammation.

If your child has signs or symptoms of rheumatic fever, you're likely to start by seeing your child's pediatrician. However, the doctor might refer you to a heart specialist (pediatric cardiologist) for some diagnostic tests.

Here's some information to help you get ready for the appointment.

What you can do

Before the appointment, make a list of:

• Your child's symptoms, including any that seem unrelated to your reason for scheduling the appointment and any that have recently been resolved
• Recent illnesses your child has had
• All medications, vitamins or other supplements your child takes or has recently taken, including doses
• Questions to ask your doctor

Take a family member or friend along, if possible, to help you remember the information you're given.

For rheumatic fever, basic questions to ask your doctor include:

• What's likely causing my child's symptoms?
• What other conditions could cause these symptoms?
• What tests will my child need?
• What is the best course of action?
• Will rheumatic fever or its treatment affect my child's other health conditions?
• How much do I need to restrict my child's activities?
• Is my child still contagious? For how long?
• What type of follow-up is needed?
• Are there brochures or other printed material that I can have? What websites do you recommend?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.

What to expect from your doctor

Your doctor is likely to ask you questions, such as:

• When did your child's symptoms begin?
• How have they changed over time?
• Has your child had a cold or flu recently? What were the symptoms?
• Has your child been exposed to strep throat?
• Was your child recently diagnosed with strep throat or scarlet fever?
• If so, did your child take all of the antibiotics as prescribed?