What is the recommended treatment for a child diagnosed with Scarlet fever?

Scarlet Fever Treatment in Children

Treat all children with scarlet fever immediately with oral Penicillin V (phenoxymethylpenicillin) 250-500 mg every 6-8 hours for a full 10 days, regardless of illness severity, to prevent serious complications including acute rheumatic fever and reduce transmission. 1, 2

First-Line Antibiotic Treatment

Penicillin V remains the gold standard treatment for scarlet fever caused by Group A Streptococcus (GAS). 1 The FDA-approved dosing for streptococcal infections including scarlet fever is:

• Adults and children ≥12 years: 125-250 mg (200,000-400,000 units) every 6-8 hours for 10 days 2
• Alternative dosing: 250-500 mg every 6-8 hours depending on severity 1, 2

The Infectious Diseases Society of America emphasizes that completing the full 10-day course is critical to prevent rheumatic fever, as shorter durations lack supporting evidence. 1 Antibiotics can be started up to 9 days after symptom onset and still effectively prevent rheumatic fever. 1

Alternative Antibiotics for Penicillin Allergy

For patients with penicillin allergy:

• First-generation cephalosporins are recommended for those without immediate hypersensitivity to β-lactam antibiotics 1
• Macrolides (azithromycin, clarithromycin) are appropriate for patients with true penicillin allergy 1

Important caveat: Some strains of Streptococcus pyogenes demonstrate macrolide resistance, which should be considered when selecting alternative therapy. 1

When Co-Amoxiclav May Be Considered

Co-amoxiclav is NOT a first-line agent for scarlet fever. 1 The American Heart Association recommends against using co-amoxiclav as first-line treatment due to its broader spectrum and higher risk of promoting antibiotic resistance. 1

Co-amoxiclav may only be considered if:

• Documented treatment failure with penicillin occurs (uncommon) 1

If co-amoxiclav is used:

• Children: 40 mg/kg/day of the amoxicillin component in 2-3 divided doses for 10 days 1
• Adults: 500 mg twice daily for 10 days 1

Critical warning: Co-amoxiclav has significantly higher rates of gastrointestinal side effects, particularly diarrhea (number needed to harm = 10), compared to penicillin. 1

Diagnostic Confirmation Before Treatment

Always confirm GAS infection before initiating antibiotics using throat culture or rapid antigen detection test (RADT). 1 The proper technique involves:

• Swab the posterior pharynx and tonsillar surfaces bilaterally 1
• If RADT is negative in children/adolescents, obtain backup throat culture (gold standard) 1
• In adults with negative RADT, backup culture is generally unnecessary due to low rheumatic fever risk 1

Do NOT test or treat if viral features predominate: conjunctivitis, coryza, cough, hoarseness, discrete ulcerative stomatitis, viral exanthem, or diarrhea. 1

Clinical Monitoring and Follow-Up

Monitor for clinical improvement within 48-72 hours of starting antibiotics. 1 If symptoms persist beyond 3-5 days of antibiotic therapy, reassess the diagnosis and consider alternative pathogens. 1

The patient becomes non-contagious after 24 hours of antibiotic therapy, allowing return to school/activities. 1

Symptomatic Management

• Antipyretics (ibuprofen or acetaminophen) for fever and pain relief 1
• NEVER use aspirin in children under 16 years due to Reye's syndrome risk 1
• Antipyretics provide symptomatic relief but do not replace the need for antibiotics 1

Critical Complications if Untreated

Early antibiotic treatment is essential to prevent:

• Suppurative complications: peritonsillar abscess 1
• Non-suppurative complications: acute rheumatic fever, acute glomerulonephritis 1, 3, 4
• Invasive disease: bacteremia, pneumonia, endocarditis, meningitis 3

The re-emergence of scarlet fever in recent years, particularly post-COVID-19 pandemic, makes early recognition and treatment increasingly important. 4, 5

Infection Control

Isolate patients for minimum 24 hours of effective antibiotic therapy. 1 Healthcare workers must use disposable gloves and aprons with strict hand hygiene before and after patient contact. 1

Routine throat cultures or treatment for asymptomatic household contacts is generally not necessary unless outbreak situations exist, in which case only those with positive cultures should be treated. 1

Common Pitfalls to Avoid

• Do not use sulfonamide antibiotics - they are associated with increased disease severity and mortality in streptococcal infections 1
• Beware of asymptomatic GAS carriers who may have positive throat cultures during viral pharyngitis episodes, mimicking acute infection; look for viral features and lack of sudden onset to differentiate 1
• Post-treatment throat cultures are not routinely recommended unless symptoms persist or recur 1