What is the likely diagnosis and treatment for a 7-year-old male patient with a recent history of pneumonia, now presenting with fever, severe sore throat, exudate on the right tonsil, and a white coating on the tongue?

Likely Diagnosis and Treatment for a 7-Year-Old with Exudative Tonsillitis

This child most likely has Group A streptococcal (GAS) pharyngitis and should be treated with high-dose oral amoxicillin (90 mg/kg/day in 2 divided doses) after confirmation with rapid antigen detection testing or throat culture. 1

Clinical Assessment Using Modified Centor Score

This patient presents with several key features that increase the probability of bacterial pharyngitis:

• Tonsillar exudate (present on right tonsil)
• Fever (present for 3-4 days)
• Severe sore throat (very sore throat reported)
• Minimal cough (only mild cough, lungs clear)
• Age 7 years (school-age child in highest risk group)

Using the modified Centor criteria, this child likely scores 3-4 points, placing the probability of GAS infection at 28-53%. 1 The white coating on tongue and unilateral tonsillar exudate are consistent with bacterial pharyngitis, though these findings alone are not specific for GAS. 2

Critical Diagnostic Requirement

Microbiological confirmation with either rapid antigen detection testing (RADT) or throat culture is mandatory before initiating antibiotic therapy. 1, 3 Clinical findings alone predict positive bacterial cultures only 80% of the time at best, and experienced clinicians consistently overestimate bacterial pharyngitis when relying on clinical impression alone. 3 The presence or absence of fever should not be used to diagnose bacterial pharyngitis or decide on antibiotic therapy, as fever is not a constant finding in GAS pharyngitis. 3

Recommended Empiric Treatment

For confirmed GAS pharyngitis in this 7-year-old:

• First-line therapy: Oral amoxicillin 90 mg/kg/day divided into 2 doses (maximum 4 g/day) 1, 4
• Alternative: Oral amoxicillin-clavulanate (amoxicillin component 90 mg/kg/day in 2 doses) 1
• For penicillin allergy: Azithromycin 10 mg/kg on day 1, followed by 5 mg/kg/day once daily on days 2-5 (maximum 500 mg day 1, then 250 mg days 2-5) 1, 4

Penicillin by intramuscular route remains the usual drug of choice for GAS infection and rheumatic fever prophylaxis, though oral amoxicillin is highly effective and more practical. 4

Important Considerations Given Recent Pneumonia History

The recent pneumonia treatment (1 month ago) raises two critical concerns:

1. Atypical pathogen consideration: Given the recent pneumonia, consider whether Mycoplasma pneumoniae or Chlamydia pneumoniae could be contributing to current symptoms. 1 These organisms have been associated with non-streptococcal acute pharyngitis in pediatric patients and can cause recurrent respiratory symptoms. 1

2. Recurrent infection risk: This represents a second respiratory infection within a short timeframe. While two episodes separated by 1 month with an asymptomatic interval can occur normally, recurrent pneumonia (defined as two or more episodes) warrants consideration of underlying structural abnormalities, immunological deficiencies, or chronic conditions if this pattern continues. 5

When to Add Macrolide Coverage

If this child does not have clear clinical, laboratory, or radiographic evidence distinguishing bacterial pharyngitis from atypical pneumonia, a macrolide (azithromycin) can be added to the β-lactam antibiotic for empiric therapy. 1 This is particularly relevant given:

• Recent pneumonia history suggesting possible atypical pathogen exposure
• White coating on tongue (though non-specific)
• School-age child at risk for Mycoplasma infection

Alternative Diagnoses to Consider

Group C streptococci can cause severe or recurrent pharyngitis with exudative tonsillitis and anterior cervical adenopathy. 1, 6 However, there is insufficient evidence for routine treatment differences from GAS.

Group B streptococcus (Streptococcus agalactiae) is not typically a significant cause of tonsillitis in children and is primarily associated with neonatal infections and infections in adults with comorbidities. 6

Common Pitfalls to Avoid

• Do not treat based on clinical findings alone without microbiological confirmation 1, 3
• Do not assume absence of fever rules out bacterial infection 3
• Do not use azithromycin monotherapy without susceptibility testing when available, as some GAS strains are resistant 4
• Do not forget that azithromycin efficacy data for preventing rheumatic fever are not available 4

Follow-Up Considerations

If symptoms persist or worsen despite appropriate antibiotic therapy, consider:

• Throat culture to confirm pathogen and susceptibility
• Evaluation for peritonsillar abscess or other suppurative complications
• Assessment for viral co-infection (though viral pharyngitis typically resolves without antibiotics)
• Re-evaluation for atypical pathogens requiring macrolide therapy