Exudative Tonsillitis in a 1-Year-Old with Elevated CRP and Normal WBC
In a 1-year-old with exudative tonsillitis, CRP 90 mg/L, normal leukocytes, and negative strep/adenovirus testing, you should strongly suspect a viral etiology—most likely Epstein-Barr virus (EBV) or other non-adenoviral viruses—rather than Mycoplasma pneumoniae, which is uncommon at this age.
Age-Based Pathogen Likelihood
Viral tonsillitis predominates in children under 3 years of age, with adenovirus being the most common viral agent (19% of cases), followed by EBV, parainfluenza, influenza A, herpes simplex, and RSV 1.
Group A streptococcal tonsillitis is most common in children ≥6 years, with 71% of streptococcal cases occurring in this older age group 2.
Mycoplasma pneumoniae is rare in children under 3 years, accounting for only 5% of febrile exudative tonsillitis overall, and is significantly more common in children over 5 years of age 1, 3.
EBV tonsillitis occurs across age groups but 70% of cases are in children under 6 years, making it a plausible diagnosis in your 1-year-old patient 2.
Interpretation of Laboratory Findings
The discordance between elevated CRP (90 mg/L) and normal WBC count is common in febrile children and does not reliably distinguish bacterial from viral etiology 4.
Studies demonstrate that CRP, WBC, and ESR cannot differentiate between adenoviral, EBV, and streptococcal tonsillitis in children 2, 1.
Elevated CRP alone does not indicate bacterial infection in young children with tonsillitis—viral infections, particularly non-streptococcal tonsillitis, commonly produce elevated inflammatory markers 4.
The mildly elevated LDH is nonspecific and can occur with viral infections, hemolysis, or tissue inflammation 3.
Diagnostic Approach
Obtain EBV serology (VCA-IgM and VCA-IgG) to evaluate for primary EBV infection, as this is a common cause of exudative tonsillitis in this age group with the clinical picture described 1, 2.
Consider testing for other respiratory viruses (parainfluenza, influenza, RSV, herpes simplex) if EBV testing is negative, as these account for a significant proportion of viral tonsillitis 1.
Mycoplasma serology is low yield in a 1-year-old given the rarity of this pathogen in children under 3 years 1, 3.
Blood cultures are not indicated unless the child appears toxic or has signs of systemic bacterial infection beyond tonsillitis 3.
Management Considerations
Avoid empiric antibiotics given the high likelihood of viral etiology in this age group (42% of febrile exudative tonsillitis in children is viral) 1.
Monitor clinical trajectory: viral tonsillitis typically improves within 7-10 days, whereas bacterial infections persist beyond 10 days or worsen after initial improvement 5.
Fever duration is key: fever persisting >3 days despite supportive care suggests bacterial superinfection or primary bacterial disease 5.
Serial CRP measurements can be helpful: CRP should decrease with appropriate management in viral illness, whereas persistent or rising CRP suggests bacterial infection or complications 3, 6.
Common Pitfalls to Avoid
Do not assume bacterial infection based solely on exudate and elevated CRP—exudative tonsillitis is frequently viral in children under 3 years 1, 2.
Do not rely on rapid strep testing alone—negative rapid tests should be confirmed by throat culture if clinical suspicion for strep is high, though this is less likely at age 1 year 3.
Do not overlook EBV as a cause of exudative tonsillitis in young children—while classic infectious mononucleosis is more common in adolescents, primary EBV infection occurs across all pediatric age groups 1, 2.
Recognize that normal WBC with elevated CRP is common in viral infections and does not rule out significant pathology 4.