What is the treatment for scarlatina in a child?

Treatment of Scarlatina (Scarlet Fever) in Children

Oral amoxicillin at 50-75 mg/kg/day divided into 2 doses (or penicillin V at 50-75 mg/kg/day in 3-4 doses) for 10 days is the definitive first-line treatment for scarlatina in children, with oral clindamycin 40 mg/kg/day in 3 doses reserved for penicillin-allergic patients. 1

First-Line Antibiotic Treatment

Penicillin remains the gold standard for Group A Streptococcus (the causative organism of scarlatina) because these bacteria demonstrate nearly 100% sensitivity to beta-lactam antibiotics, with no documented resistance. 2

Preferred Oral Regimens:

• Amoxicillin 50-75 mg/kg/day divided into 2 doses for 10 days (better palatability and compliance than penicillin V) 1, 3
• Penicillin V 50-75 mg/kg/day divided into 3-4 doses for 10 days (traditional first-line agent) 1, 3

Duration of Therapy:

• The full 10-day course is critical to prevent suppurative complications and acute rheumatic fever, even though clinical improvement typically occurs within 24-48 hours 3, 4
• Bacteriologic failure rates with penicillin have increased to approximately 30% when the full 10-day course is not completed, primarily due to non-compliance 4

Treatment for Penicillin-Allergic Patients

For children with documented penicillin allergy, oral clindamycin 40 mg/kg/day divided into 3 doses for 10 days is the preferred alternative. 1, 5

Alternative Options Based on Allergy Severity:

• Non-immediate hypersensitivity (rash): First-generation cephalosporins such as cephalexin 75-100 mg/kg/day in 3-4 doses may be used under supervision 1, 6
• Immediate Type I hypersensitivity (anaphylaxis): Clindamycin is mandatory; cephalosporins are contraindicated 1, 5

Important Caveat About Macrolides:

• Macrolides (azithromycin, clarithromycin, erythromycin) should NOT be used routinely for scarlatina, despite being commonly prescribed 3, 7
• Erythromycin-resistant Group A Streptococcus cultures have increased 9-fold, reaching resistance rates of up to 26% in some regions 2, 7
• Macrolides should be reserved only for patients with proven severe beta-lactam allergy where clindamycin is not available 3, 7

Severe or Hospitalized Cases

For severe scarlatina requiring hospitalization (toxic appearance, inability to tolerate oral intake, complications), intravenous penicillin G 100,000-250,000 U/kg/day every 4-6 hours or ampicillin 200 mg/kg/day every 6 hours is preferred. 1

Parenteral Alternatives:

• Ceftriaxone 50-100 mg/kg/day every 12-24 hours (convenient once-daily dosing for outpatient parenteral therapy) 1, 6
• Cefotaxime 150 mg/kg/day every 8 hours 1
• Clindamycin 40 mg/kg/day every 6-8 hours IV for penicillin-allergic patients 1, 5

Critical Clinical Considerations

Common Pitfalls to Avoid:

• Underdosing amoxicillin: Using 40-45 mg/kg/day instead of the recommended 50-75 mg/kg/day leads to treatment failure 1
• Incomplete treatment course: Stopping antibiotics when symptoms resolve (typically 2-3 days) rather than completing the full 10-day course increases risk of rheumatic fever 4
• Inappropriate macrolide use: Prescribing azithromycin or clarithromycin as first-line therapy when penicillin/amoxicillin should be used 3, 7

When to Reassess:

• If no clinical improvement occurs within 48-72 hours, consider treatment failure, non-compliance, reinfection from household contacts, or alternative diagnosis 4, 7
• Bacteriologic failure may occur even with clinical improvement; this is more common with macrolides than beta-lactams 7

Household Contact Management:

• Reexposure to Streptococcus-infected family members is a major cause of treatment failure 4
• Consider treating symptomatic household contacts simultaneously to prevent ping-pong reinfection 4