Published: 18 Jun 2025

ICD9: 390      ICD10: 8.9.1      ICD11: 1B40

Rheumatic fever is a serious inflammatory condition that can develop as a complication of a streptococcal (strep) throat or scarlet fever infection, both caused by *Streptococcus pyogenes* bacteria.
It primarily affects children aged 5-15 but can occur in adults, though less frequently.

Here's a breakdown of key aspects of rheumatic fever:

Cause:

Untreated or inadequately treated Strep Throat or Scarlet Fever: Rheumatic fever doesn't happen *during* a strep infection. It's a delayed immune response *after* the strep infection. If strep throat or scarlet fever isn't treated with antibiotics, or is treated late, the body's immune system can mistakenly attack its own tissues.
Autoimmune Response: The antibodies produced to fight the strep bacteria begin to target tissues in the body that have similar proteins to the strep bacteria. This is known as molecular mimicry.

Organs Affected:

Rheumatic fever can affect multiple organs, but the most significant concern is the heart. Other affected areas include:

Heart: This is the most serious manifestation. Inflammation can affect the heart valves (leading to rheumatic heart disease, a chronic condition), heart muscle (myocarditis), and the outer lining of the heart (pericarditis). Damage to the heart valves can lead to narrowing (stenosis) or leaking (regurgitation), which can cause heart failure.
Joints: Arthritis is a common symptom, typically affecting large joints like knees, ankles, elbows, and wrists. The pain is usually migratory, meaning it moves from one joint to another.
Brain: Sydenham's chorea is a neurological disorder characterized by involuntary, jerky movements, often affecting the face, arms, and legs. It can also cause emotional lability (mood swings).
Skin:
*Erythema marginatum:* A painless, ring-shaped rash with a pale center and slightly raised edges. It's not always present.
*Subcutaneous nodules:* Small, painless lumps under the skin, usually near joints. These are also less common.

Symptoms:

Symptoms typically develop 1-5 weeks after a strep throat infection. Not all individuals will experience all symptoms. Common symptoms include:

Fever
Painful, tender joints (arthritis) - often migratory
Chest pain or shortness of breath (if the heart is affected)
Fatigue
Unusual movements (Sydenham's chorea)
Rash (erythema marginatum)
Nodules under the skin
Heart murmur

Diagnosis:

Diagnosis is based on the *Jones Criteria*, which include:

Evidence of a recent strep infection: This is confirmed by a throat culture, rapid strep test, or elevated levels of anti-streptolysin O (ASO) or other streptococcal antibodies in the blood.
Major Criteria: Two major criteria OR one major criterion plus two minor criteria must be present.

Major Criteria:
Carditis (inflammation of the heart)
Polyarthritis (inflammation of multiple joints)
Sydenham's chorea
Erythema marginatum
Subcutaneous nodules

Minor Criteria:
Fever
Arthralgia (joint pain, but not inflammation)
Elevated erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) - inflammatory markers
Prolonged PR interval on ECG (electrocardiogram)

Treatment:

The goals of treatment are:

Eradicate the strep infection: Antibiotics (usually penicillin or amoxicillin) are given to eliminate any remaining strep bacteria.
Reduce inflammation: Anti-inflammatory medications, such as aspirin or corticosteroids, are used to reduce inflammation and relieve symptoms.
Manage symptoms: Medications may be needed to manage heart failure, chorea, or other complications.
Prevent recurrent attacks: Long-term antibiotic prophylaxis (usually penicillin injections or oral penicillin) is crucial to prevent future strep infections and subsequent episodes of rheumatic fever. The duration of prophylaxis depends on the severity of the initial attack and the presence of heart involvement.

Prevention:

The best way to prevent rheumatic fever is to promptly diagnose and treat strep throat and scarlet fever with antibiotics. This is why it's so important to see a doctor when you suspect you or your child has strep throat.

Prognosis:

The long-term outlook depends on the severity of the heart involvement. Rheumatic heart disease, a chronic condition resulting from heart valve damage, can lead to significant disability and even death. However, with proper treatment and prevention, many people with rheumatic fever can live relatively normal lives. Regular follow-up with a cardiologist is essential, especially for those with rheumatic heart disease.