Not Just a Sore Throat: Why Group A Strep Still Belongs on Our Radar

Group A streptococcus (GAS) rarely starts in the intensive care unit (ICU) but often ends there. From toxic shock syndrome to necrotizing fasciitis, many of our sickest ICU patients trace their illness to what began as a seemingly simple sore throat. This Concise Critical Appraisal discusses the latest update from the Infectious Diseases Society of America (IDSA) on the diagnosis of GAS pharyngitis.¹ The update deserves our attention—not because intensivists diagnose sore throats every day but because our patients often face the downstream consequences when those early diagnoses are missed, delayed, or overtreated.

What the New Guidelines Say
The 2025 IDSA update focuses on risk assessment and diagnostic testing for GAS pharyngitis, addressing who should be tested, who should not be treated, and how clinical scores should guide these decisions. The key shift is toward a structured, score-based triage—specifically using the Centor or McIsaac scoring tools to decide who needs testing.^2,3 Historically, clinicians often relied on gestalt and broad rapid testing, swabbing nearly everyone with a sore throat.⁴ The new guidance explicitly discourages this practice, emphasizing structured decision-making to identify patients at low risk (in whom testing can safely be avoided) and intermediate to high risk (in whom testing is warranted).

Why It Matters
This change is not just about sore throats—it is about diagnostic precision and antibiotic stewardship, both cornerstone principles of critical care. By limiting testing in low-risk patients, the guideline reduces overdiagnosis of carriers and unnecessary antibiotic use—key drivers of antimicrobial resistance and Clostridioides difficile infection. At the same time, it preserves vigilance for high-risk or complicated patients, such as those with household exposure, prior rheumatic fever, immunosuppression, or signs of deep infection (e.g., peritonsillar or retropharyngeal abscess, neck swelling, or systemic toxicity). These exceptions ensure that clinicians do not miss the small subset of GAS infections that can spiral into invasive disease.

Comparing the New Guidance to Prior Practice
Earlier versions of GAS management—especially before rapid molecular tests became common—favored broad testing or even empiric treatment based on symptoms alone. The classic teaching was simple: if it looks like strep, test and treat it. Now, the goal is to test less but test smarter:

• Low-risk patients (score 0–1): No testing nor antibiotics.
• Intermediate-risk patients (score 2–3): Test using a rapid antigen or molecular assay.
• High-risk patients (score ≥4 or red-flag features): Test and strongly consider empiric coverage while awaiting confirmation.

The guideline also emphasizes avoiding unnecessary testing in children under age three years unless there is a clear exposure history because GAS pharyngitis is rare in that age group. This risk-based triage approach is supported by decades of validation data. In the original studies, low Centor or McIsaac scores corresponded to less than a 10% probability of GAS, while high scores approached 50% to 60%.2,3 These thresholds give clinicians a rational way to decide when a test will change management and when it will not.

In summary, these new IDSA recommendations may seem ambulatory, but they have implications across the care continuum. Emergency departments, urgent care centers, and primary care offices all serve as the front line for identifying GAS infections before they become life-threatening. The updated IDSA guideline is about precision—fewer false positives, fewer unnecessary antibiotics, and earlier recognition of true disease. For ICU clinicians, the goal is not to memorize scoring systems but to understand how disciplined decision-making reduces the cascade of antibiotic exposure, microbiome disruption, and resistance that complicates critical illness. When early decisions are guided by data, fewer “simple sore throats” end up in our units.

References:

1. Infectious Diseases Society of America. Clinical practice guideline update by the Infectious Diseases Society of America  on group A streptococcal (GAS) pharyngitis. October 14, 2025. Accessed December 8, 2025. https://www.idsociety.org/practice-guideline/streptococcal-pharyngitis2/
2. Fine AM, Nizet V, Mandl KD. Large-scale validation of the Centor and McIsaac Scores to predict group A streptococcal pharyngitis. JAMA Intern Med. 2012 Jun 11;172(11):847-852. 
3. McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE. Empirical validation of guidelines for the management of pharyngitis in children and adults. JAMA. 2004 Apr 7;291(13):1587-1595.
4. Aalbers J, O'Brien KK, Chan WS, et al. Predicting streptococcal pharyngitis in adults in primary care: a systematic review of the diagnostic accuracy of symptoms and signs and validation of the Centor score. BMC Med. 2011 Jun 1;9:67.