is a delayed, immune-mediated complication of group A streptococcal pharyngitis. Unlike most rheumatic disease of childhood it has a known trigger, and that makes it preventable at two separate points: the first attack, by treating the pharyngitis properly, and every attack after that, by protecting the child from further streptococcal infections. Prevention matters out of proportion to the discomfort of a sore throat because the valves that are scarred during an attack do not recover, and each recurrence adds to the damage.
Primary prevention: treat the pharyngitis properly
This is the single most effective intervention. Antibiotic treatment for streptococcal pharyngitis started within 9 days of the onset of the sore throat prevents the first episode of rheumatic fever; treatment started later still treats the infection but no longer prevents the rheumatic complication. There is therefore time to confirm the diagnosis with a culture or rapid test rather than treating blindly.
Regimens used for group A streptococcal pharyngitis include:
| Regimen | Dose | Duration |
|---|---|---|
| Amoxicillin, oral | 50 mg/kg once daily (maximum 1,000 mg), or 25 mg/kg twice daily (maximum 500 mg per dose) | 10 days |
| Penicillin V, oral | 250 mg two to three times daily (children) | 10 days |
| Benzathine penicillin G, intramuscular | 600,000 units if 27 kg or under; 1,200,000 units if over 27 kg | Single dose |
Group A Streptococcus has never been shown to be resistant to penicillin, so amoxicillin is sufficient and clavulanate adds nothing; its wider spectrum is unnecessary and works against antibiotic stewardship, the practice of using the narrowest antibiotic that will work. For children with penicillin allergy, a cephalosporin, clindamycin or a macrolide can be used, with local resistance patterns in mind.
Screening scores such as the (absence of cough, tender anterior cervical nodes, fever, tonsillar exudate or swelling, and age 3-14 years) help decide who should be tested, but they are triage tools rather than diagnostic rules, and clinical judgement overrides them.
Secondary prevention: prevent recurrence
Once a child has had rheumatic fever, each subsequent streptococcal infection risks another attack and further valve damage. Secondary prophylaxis — regular antibiotics given to prevent new streptococcal infections — is therefore long-term, and the standard regimen is intramuscular , a long-acting injectable form of penicillin:
| Weight | Dose | Interval |
|---|---|---|
| 27 kg or under | 600,000 units | Every 4 weeks; every 3 weeks in settings of high streptococcal exposure |
| Over 27 kg | 1,200,000 units | Every 4 weeks; every 3 weeks in settings of high streptococcal exposure |
Oral penicillin V twice daily is an alternative where injections are not feasible, and sulfadiazine or a macrolide is used in penicillin-allergic patients.
Duration is decided by the cardiac findings and by local guidelines, which differ in detail; the widely followed thresholds are:
| Cardiac status | Duration |
|---|---|
| No carditis | 5 years after the last attack, or until 21 years of age, whichever is longer |
| Carditis with no residual valvular disease | 10 years after the last attack, or until 21 years of age, whichever is longer |
| Carditis with persistent valvular disease | 10 years after the last attack, or until 40 years of age, whichever is longer; lifelong prophylaxis is sometimes recommended |
Some national protocols use 18 rather than 21 years as the age threshold and 21-30 days rather than 28 days as the injection interval, so the schedule in use where the patient is being managed determines the exact numbers. If a further episode of rheumatic fever occurs during prophylaxis, prophylaxis continues and is usually intensified.
Prevention works here because the trigger is a known bacterium that can be found and treated. A chronic arthritis that begins without any identifiable trigger cannot be approached that way, and has to be recognised from its pattern instead.