Scarlet Fever Treatment Guidelines

First-Line Treatment

The American Academy of Pediatrics and the Infectious Diseases Society of America recommend penicillin or amoxicillin for 10 days as the first-line treatment for scarlet fever, with penicillin V 250 mg four times daily or 500 mg twice daily for adolescents/adults, or amoxicillin 50 mg/kg once daily (maximum 1,000 mg) for children 1, 2
Penicillin remains the drug of choice due to proven efficacy, safety, narrow spectrum, and low cost, with no documented penicillin resistance in Group A Streptococcus (GAS) anywhere in the world 1, 2
Amoxicillin is often preferred in young children due to better palatability of the suspension 1, 2

For non-immediate/non-anaphylactic reactions, first-generation cephalosporins are safe and preferred, with cephalexin 20 mg/kg/dose twice daily (maximum 500 mg/dose) for 10 days 3, 2
For immediate/anaphylactic reactions, avoid all beta-lactams including cephalosporins due to up to 10% cross-reactivity risk, and use clindamycin 7 mg/kg/dose three times daily (maximum 300 mg/dose) for 10 days instead 1, 3
Azithromycin 12 mg/kg once daily (maximum 500 mg) for 5 days is an alternative, but note that macrolide resistance is 5-8% in the United States, making clindamycin more reliable 3, 2

A full 10-day course is mandatory for all antibiotics except azithromycin to achieve maximal bacterial eradication and prevent acute rheumatic fever 1, 2
Shortening the course by even a few days results in appreciable increases in treatment failure rates and risk of rheumatic fever 3
For symptom management, use acetaminophen or NSAIDs (ibuprofen) for fever and pain control, and avoid aspirin in children due to risk of Reye syndrome 3, 4
Corticosteroids are not recommended for adjunctive therapy 3

Do not use trimethoprim-sulfamethoxazole (Bactrim) due to 50% resistance rate, or tetracyclines or sulfonamides as they fail to eradicate streptococci effectively 3, 4, 2
Do not prescribe cephalosporins to patients with immediate/anaphylactic penicillin reactions due to 10% cross-reactivity risk 1, 3
Do not shorten treatment duration below 10 days (except azithromycin's 5-day course) as this increases treatment failure and complication risk 3, 2

When invasive disease is suspected, combination therapy with clindamycin plus penicillin is essential, and clindamycin suppresses streptococcal toxin and cytokine production 5
Routine post-treatment throat cultures are not recommended for asymptomatic patients who have completed therapy, but testing should be considered in special circumstances such as patients with a history of rheumatic fever 1, 3