Rheumatic fever and rheumatic heart disease

Lesion

After a strep throat, the immune system can attack the heart. Repeated attacks scar the valves, especially the mitral valve.

Updated Nov 12, 2026

Key points

Onset about 2 to 4 weeks after group A streptococcal pharyngitis (not skin infection); children 5 to 15.
Jones major criteria: carditis, migratory polyarthritis of large joints, Sydenham chorea, erythema marginatum, subcutaneous nodules; plus evidence of recent strep infection.
Aschoff bodies: foci of T cells, plasma cells and activated macrophages (Anitschkow ‘caterpillar’ cells) around fibrinoid necrosis.
Acute valvulitis: small warty vegetations along lines of closure; MacCallum plaques in the left atrium.
Chronic disease: mitral stenosis with fused commissures and thick, short, fused chordae (‘fish-mouth’ or ‘buttonhole’ valve); mitral is affected almost always, aortic often.
Chronic mitral stenosis leads to left atrial dilation, atrial fibrillation, mural thrombi, pulmonary hypertension and right heart failure.

What it is

Acute rheumatic fever is an immune-mediated multisystem disease that follows group A streptococcal pharyngitis by a few weeks in susceptible children. Antibodies and T cells against streptococcal M protein cross-react with heart, joint, skin and brain proteins (molecular mimicry). Acute carditis involves all three layers (pancarditis). Recurrent episodes cause chronic rheumatic heart disease, a fibrotic deformity of valves, mainly the mitral, that remains the commonest acquired heart disease of children and young adults in low- and middle-income countries, including parts of Latin America.

Structure

Acute: fibrinous pericarditis; Aschoff bodies in the myocardium; small verrucae along valve closure lines.
Chronic mitral valve: thick, fibrotic leaflets, commissural fusion, shortened thickened fused chordae, calcification; neovascularisation of the leaflets.

Step by step

Group A streptococci infect the pharynx of a genetically susceptible child.
The immune response targets M protein and other bacterial antigens.
Antibodies and CD4 T cells cross-react with cardiac myosin, valve proteins and other tissues.
Acute inflammation affects pericardium, myocardium (Aschoff bodies) and valves (verrucous vegetations).
Repeated infections cause repeated attacks; valves heal by fibrosis, fusion and calcification.
Years later the scarred valves narrow or leak: chronic rheumatic heart disease.

Clinical notes

Secondary prophylaxis with penicillin prevents recurrences and progression.
Rheumatic heart disease is still common in parts of Latin America and the Caribbean and among underserved communities.

Test yourself

Think of the answer, then tap the question to see it.

What are Aschoff bodies?

Inflammatory foci in acute rheumatic carditis: T cells, plasma cells and plump macrophages (Anitschkow cells) around fibrinoid necrosis.

Which valve is almost always involved in chronic rheumatic heart disease?

The mitral valve, typically with stenosis and a fish-mouth deformity.

What is the mechanism of rheumatic fever?

Molecular mimicry: antibodies and T cells against streptococcal M protein cross-react with heart and other host proteins.

Which infection precedes rheumatic fever?

Group A streptococcal pharyngitis, a few weeks earlier.

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Connections

Microorganisms1

Streptococcus pyogenes

← All of general pathology

Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: Rheumatic fever: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025); Current Situation of Acute Rheumatic Fever and Rheumatic Heart Disease in Latin America and the Caribbean: A Systematic Review (Global heart, 2022).

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Representative model, for educational purposes only.