Group A Streptococcal Pharyngitis in 2-Month-Old Infants
No, a 2-month-old infant is very unlikely to contract Group A streptococcal (GAS) pharyngitis, as this infection is primarily a disease of children 5 to 15 years of age and is uncommon in children younger than 3 years. 1
Age-Related Epidemiology
- GAS pharyngitis predominantly affects school-age children (5-15 years) and occurs most commonly during winter and early spring in temperate climates 1
- GAS is an uncommon cause of pharyngitis in preschool children, though outbreaks in childcare settings have been documented 1
- The low prevalence of GAS pharyngitis in children <3 years of age limits the usefulness of diagnostic testing in this age group 1
Clinical Presentation Differs in Young Infants
When GAS infection does occur in very young children, the presentation is atypical:
- Infants with GAS upper respiratory tract infections may present with excoriated nares or purulent nasal discharge rather than classic pharyngitis 1
- GAS infection in children <3 years old is often associated with fever, mucopurulent rhinitis, excoriated nares, and diffuse adenopathy 1
- Exudative pharyngitis is rare in this age group 1
Low Risk of Acute Rheumatic Fever
- Reports of acute rheumatic fever (ARF) in children <3 years of age are very rare 1
- In a study of 541 new ARF cases from Salt Lake City, only 5% involved individuals <5 years of age, with a median age of 4 years 1
- Rheumatic fever is rare in children younger than 3 years of age in the United States 1
- This low risk is thought to occur because repeated exposures to GAS or priming of the immune system may be necessary before an immune response develops that can lead to rheumatic fever 1
Important Clinical Caveat
While extremely rare, case reports do exist of streptococcal pharyngitis in 2-month-old infants, particularly when there is documented GAS infection in a parent with similar symptoms 2. In such scenarios with clear household exposure and compatible clinical findings, GAS pharyngitis should be considered as a possible differential diagnosis 2.
Practical Implications
- Routine testing for GAS pharyngitis in a 2-month-old is generally not warranted given the very low prevalence in this age group 1
- If pharyngitis symptoms occur in an infant this young, viral etiologies are far more likely, and other serious bacterial infections appropriate to this age group should be considered first 1
- The most common serious bacterial infection in febrile 2-month-old infants is urinary tract infection (17.9%), followed by bacteremia (2%) and bacterial meningitis (0.9%), with E. coli being the leading pathogen 1