What is the recommended treatment for a patient presenting with Scarlatina?

Treatment of Scarlet Fever

For patients presenting with scarlet fever, initiate oral Penicillin V (phenoxymethylpenicillin) 250-500 mg every 6-8 hours for a full 10-day course immediately upon diagnosis to prevent rheumatic fever and reduce infectivity. 1, 2

Primary Antibiotic Regimen

Penicillin V remains the first-line treatment as recommended by the American Heart Association and Infectious Diseases Society of America, with the following specific dosing: 1

Adults and Children ≥40 kg:

• 500 mg every 12 hours OR 250 mg every 8 hours for 10 days 2
• Alternative dosing: 500 mg twice daily or 250 mg three times daily 1

Pediatric Patients (≥3 months and <40 kg):

• 25 mg/kg/day divided every 12 hours OR 20 mg/kg/day divided every 8 hours for 10 days 2

Infants <3 months:

• Maximum 30 mg/kg/day divided every 12 hours for 10 days due to immature renal function 2

Critical Treatment Principles

The 10-day duration is non-negotiable - this full course is essential to prevent acute rheumatic fever, even if symptoms resolve earlier. 1, 2 Treatment can be initiated up to 9 days after symptom onset and still effectively prevent rheumatic fever. 1

The patient becomes non-contagious after 24 hours of appropriate antibiotic therapy, which is crucial for infection control and return-to-school/work decisions. 1

Alternative Regimens for Penicillin Allergy

For Non-Immediate Hypersensitivity (e.g., rash):

First-generation cephalosporins are recommended by the Infectious Diseases Society of America: 1

• Cephalexin or cefazolin are appropriate alternatives 3

For True Penicillin Allergy (Type I Hypersensitivity):

Macrolides are the recommended alternative, though resistance patterns must be considered: 1

• Erythromycin or azithromycin
• Important caveat: Macrolide resistance in Group A Streptococcus has increased, with erythromycin-resistant strains rising to 1.9% in some surveillance data 4
• Some strains show cross-resistance between macrolides and clindamycin 5

Clindamycin is an alternative option if local resistance rates are low (<10%). 5

When NOT to Use Certain Antibiotics

Never use sulfonamide antibiotics - the CDC explicitly advises against their use due to associations with increased disease severity and mortality in streptococcal infections. 1

Co-amoxiclav (amoxicillin-clavulanate) should NOT be used as first-line therapy despite its effectiveness, as the American Heart Association gives it a Class III recommendation due to broader spectrum coverage, higher gastrointestinal side effects (number needed to harm = 10), and increased antibiotic resistance risk. 1 It may only be considered in documented treatment failure with penicillin, which is uncommon. 1

Diagnostic Confirmation Before Treatment

Obtain throat culture or rapid antigen detection test (RADT) to confirm Group A Streptococcus before initiating antibiotics whenever possible, as recommended by the American Academy of Pediatrics and Infectious Diseases Society of America. 1 However, in typical presentations with characteristic rash, fever, and pharyngitis, empiric treatment should not be delayed while awaiting results. 6

Proper specimen collection involves swabbing the posterior pharynx and tonsillar surfaces bilaterally. 1

Monitoring and Follow-Up

Expect clinical improvement within 48-72 hours of starting antibiotics. 1 If symptoms persist beyond 3-5 days of appropriate antibiotic therapy, reassess the diagnosis and consider:

• Alternative pathogens 1
• Treatment compliance issues
• Antibiotic resistance (though rare with penicillin in Group A Streptococcus)

Post-treatment throat cultures are NOT routinely recommended unless symptoms persist or recur. 1

Symptomatic Management

Antipyretics (acetaminophen or ibuprofen) may be used for fever control but do not replace the need for antibiotics. 1

Never use aspirin in children under 16 years due to the risk of Reye's syndrome. 1

Infection Control Measures

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

Routine treatment of asymptomatic household contacts is generally not necessary unless there is an outbreak situation, in which case throat cultures should be performed and only culture-positive contacts treated. 1

Common Pitfalls to Avoid

• Do not stop antibiotics early even if the patient feels better - the full 10-day course is mandatory to prevent rheumatic fever 2
• Do not use tetracyclines in children <8 years of age 5
• Do not prescribe macrolides without considering local resistance patterns 4
• Do not use rifampin as monotherapy or adjunctive therapy for streptococcal pharyngitis 5