Scarlet Fever Treatment
Treat scarlet fever immediately with oral Penicillin V (phenoxymethylpenicillin) 250-500 mg every 6-8 hours for a full 10-day course, regardless of symptom severity, to prevent serious complications including rheumatic fever and reduce community transmission. 1, 2
Primary Antibiotic Regimen
Penicillin V remains the gold standard first-line treatment as recommended by the American Heart Association and Infectious Diseases Society of America, with dosing of 250-500 mg (200,000-400,000 units) every 6-8 hours for 10 days in adults and children ≥12 years. 1, 2
Alternative dosing schedules include 500 mg twice daily or 250 mg three times daily, though the every 6-8 hour regimen provides more consistent drug levels. 1
The full 10-day course is mandatory to eradicate Group A Streptococcus and prevent acute rheumatic fever, even if symptoms resolve earlier. 1, 2, 3
Alternative Antibiotics for Penicillin Allergy
First-generation cephalosporins (e.g., cephalexin) are recommended for patients without immediate hypersensitivity reactions to β-lactam antibiotics. 1
Macrolides (e.g., azithromycin, clarithromycin) should be reserved for patients with true penicillin allergy, though be aware that some Streptococcus pyogenes strains demonstrate macrolide resistance. 1
Never use sulfonamide antibiotics as they are associated with increased disease severity and mortality in streptococcal infections per CDC guidance. 1
Critical Timing Considerations
Antibiotics can be initiated up to 9 days after symptom onset and still effectively prevent rheumatic fever, though earlier treatment reduces the infectivity period and overall morbidity. 1
Patients become non-contagious after 24 hours of appropriate antibiotic therapy, which is the minimum isolation period required in healthcare settings. 1
Treatment should never be delayed pending laboratory confirmation when clinical presentation is consistent with scarlet fever (fever ≥38°C, sandpaper-like rash, pharyngitis, strawberry tongue). 1
Diagnostic Confirmation
Throat culture or rapid antigen detection test (RADT) should be performed to confirm Group A Streptococcus infection, with specimens obtained from the posterior pharynx and tonsillar surfaces bilaterally. 1
Throat culture remains the reference standard, providing definitive identification of Group A β-hemolytic streptococci. 1
However, do not withhold antibiotics while awaiting culture results if clinical suspicion is high, as early treatment is critical. 1
Monitoring and Follow-Up
Assess clinical response within 48-72 hours of initiating antibiotics, looking specifically for fever resolution and improvement in throat symptoms. 1
If symptoms persist beyond 3-5 days of antibiotic therapy, reassess the diagnosis and consider alternative pathogens or complications. 1
Post-treatment throat cultures are not routinely recommended unless symptoms persist or recur. 1
Management of Household Contacts
Routine throat cultures or prophylactic treatment of asymptomatic household contacts is generally unnecessary in sporadic cases. 1
In outbreak situations (e.g., schools, daycare centers), perform throat cultures for all exposed individuals and treat only those with positive results. 1
Common Pitfalls to Avoid
Never use aspirin for fever control in children under 16 years due to the risk of Reye's syndrome; use acetaminophen or ibuprofen instead. 1
Do not assume co-amoxiclav (amoxicillin-clavulanate) is equivalent to penicillin—it has higher gastrointestinal side effects (number needed to harm of 10) and broader spectrum, making it inappropriate as first-line therapy. 1
Antipyretics provide symptomatic relief but do not replace the need for antibiotics, which are essential to prevent suppurative and non-suppurative complications. 1
The characteristic rash typically begins on the trunk and spreads to extremities with accentuation in the perineal region, and may desquamate early—this should not be confused with other exanthems. 1