Centor Score (Modified/McIsaac) for Strep Pharyngitis

Age

Exudate or Swelling on Tonsils

Tender/Swollen Anterior Cervical Lymph Nodes

Temperature >38°C (100.4°F)

Cough

Centor Score (Modified): 0

–

Estimates probability that pharyngitis is streptococcal, and suggests management course.

Why Use

Most pharyngitis is viral and does not respond to antibiotic treatment. The Centor Score attempts to predict which patients will have culture-confirmed streptococcal infections of their pharynx to help determine which patients to test in the first place. The newer FeverPAIN Score is similar, but the Centor Score distinguishes between adolescents/young adults and pre-adolescents—important because strep carrier rates are higher in preadolescents than adolescents/young adults, and older patients are more likely to have severe symptoms and develop suppurative complications ( Mitchell 2011 ).

When to Use

Children with pharyngitis, primarily; the risk of GAS decreases significantly with age into adulthood.

Formula

Addition of the selected points: Criteria Points Age 3-14 years +1 15-44 years 0 ≥45 years -1 Exudate or swelling on tonsils No 0 Yes +1 Tender/swollen anterior cervical lymph nodes No 0 Yes +1 Temp >38°C (100.4°F) No 0 Yes +1 Cough Cough present 0 Cough absent +1

Pearls / Pitfalls

The Centor Score correlates directly with risk of positive throat culture for GAS (Group A Streptococcus). New 2012 guidelines from the IDSA (Infectious Disease Society of America) no longer recommend empiric treatment for patients alone; they recommend testing patients that are at higher risk for strep pharyngitis, but not giving antibiotics until a rapid test is positive or a throat culture is positive. The modified criteria by McIsaac et al include an age component, along with tonsillar swelling, as part of the rule. GAS is incredibly rare in patients under 3 and less common in older adults, so this can help clinicians risk stratify patients. Most cases of pharyngitis are viral in origin, and with the rare incidence of rheumatic fever, along with the questionable benefits of early antibiotics to prevent sequelae like peritonsillar abscess, antibiotics are prescribed much less often. Steroids (like dexamethasone) and NSAIDS often provide similar pain relief and resolution of symptoms to antibiotics.

Critical Actions

Carefully consider patients with symptom duration longer than 3 days, even though the Centor Score does not apply. While symptoms are not compatible with a diagnosis of acute pharyngitis, these patients require evaluation for suppurative complications (peritonsillar abscess or Lemierre syndrome), or viral infections in adult patients (infectious mononucleosis or acute HIV) (Centor 2017).

Advice

Steroids and NSAIDS improve symptoms; antibiotics are often indicated in streptococcal pharyngitis, but do not prevent its suppurative complications, like peritonsillar abscess.

More Information

Interpretation: Centor Score Probability of strep pharyngitis Recommendation 0 1-2.5% No further testing or antibiotics. 1 5-10% 2 11-17% Optional rapid strep testing and/or culture. 3 28-35% Consider rapid strep testing and/or culture. ≥4 51-53% Consider rapid strep testing and/or culture. Empiric antibiotics may be appropriate depending on the specific scenario.