What is the likelihood of a 16-month-old child having streptococcal (strep) pharyngitis?

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Last updated: June 11, 2025View editorial policy

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From the Guidelines

A 16-month-old child has an extremely low likelihood of developing streptococcal pharyngitis, with the incidence of strep throat in this age group estimated to be less than 5% of all pharyngitis cases. This low prevalence is due to several factors related to early childhood development, including fewer exposures to group A streptococcus and an immature immune system and oropharyngeal receptors 1. When evaluating a 16-month-old with sore throat symptoms, other causes such as viral infections (particularly respiratory syncytial virus, rhinovirus, or adenovirus) are far more likely explanations.

Key Points to Consider

  • The American Academy of Pediatrics and the Infectious Diseases Society of America recommend against routine testing for strep throat in children under 3 years unless there are specific risk factors such as a household contact with confirmed strep infection or if the child shows classic symptoms along with high fever and tender cervical lymphadenopathy 1.
  • Diagnostic studies for GAS pharyngitis are not indicated for children <3 years old because acute rheumatic fever is rare in children <3 years old and the incidence of streptococcal pharyngitis and the classic presentation of streptococcal pharyngitis are uncommon in this age group 1.
  • Selected children <3 years old who have other risk factors, such as an older sibling with GAS infection, may be considered for testing 1.

Clinical Implications

  • Routine testing for strep throat is not recommended in children under 3 years unless there are specific risk factors, and other causes of sore throat symptoms should be considered first 1.
  • A negative test result for GAS provides reassurance that the patient likely has a viral cause of pharyngitis, and antibiotics can be safely avoided 1.

From the Research

Streptococcal Pharyngitis in Children

The likelihood of a 16-month-old child having streptococcal pharyngitis can be assessed based on various factors, including symptoms and diagnostic methods.

  • The most common bacterial cause of pharyngitis is Group A β-hemolytic streptococcus (GABHS), commonly known as strep throat 2.
  • 15-35% of children in the United States with pharyngitis have a GABHS infection 2.
  • Symptoms of GABHS overlap with non-GABHS and viral causes of acute pharyngitis, complicating the problem of diagnosis 2.
  • Clinical guidelines recommend using clinical decision rules to assess the risk of group A beta-hemolytic streptococcal infection, followed by rapid antigen testing if a diagnosis is unclear, before prescribing antibiotics 3.

Diagnostic Methods and Treatment

  • Fever, tonsillar exudate, cervical lymphadenitis, and patient ages of 3 to 15 years increase clinical suspicion of streptococcal pharyngitis 3.
  • A cough is more suggestive of a viral etiology 3.
  • Penicillin and amoxicillin are first-line antibiotics, with a recommended course of 10 days; first-generation cephalosporins are recommended for patients with nonanaphylactic allergies to penicillin 3, 4, 5.
  • There is significant resistance to azithromycin and clarithromycin in some parts of the United States 3.

Age-Specific Considerations

  • The studies do not provide specific data on the likelihood of streptococcal pharyngitis in 16-month-old children 2, 3, 4, 5.
  • However, it is known that children under the age of 3 are less likely to have streptococcal pharyngitis, and viral causes are more common in this age group 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Streptococcal Pharyngitis: Rapid Evidence Review.

American family physician, 2024

Research

Diagnosis and treatment of streptococcal pharyngitis.

American family physician, 2009

Research

Does the choice of antibiotic affect outcome in strep throat?

Annals of emergency medicine, 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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