Centor’s Corner: Thoughts on Diagnosis and Management of Pharyngitis

Thoughts on diagnosis and management of pharyngitis from Dr. Centor, the creator of the Centor Score for Strep Pharyngitis.

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First, we must define acute pharyngitis: no more than 3-5 days of symptoms.

Second, we should understand that pre-adolescent pharyngitis has major differences from adolescent/young adult pharyngitis (Mitchell 2011).

Here are the differences: Pre-adolescent pharyngitis is group A strep vs viral. In contrast, adolescent/young adult pharyngitis has a much broader differential: GAS, group C/G strep, Fusobacterium necrophorum, infectious mononucleosis, acute HIV. Antibiotics decrease duration of symptoms for GAS pharyngitis in adolescents/adults but not pre-adolescents (Zwart 2000; Zwart 2003).

Current guidelines for children are logicalCurrent guidelines for adolescent/adults follow from an assumption that I am happy to argue against.

Third, all guidelines recommend not to test or treat for Centor scores (with or without McIsaac modification) of 0 or 1. The pre-test probabilities are very low and most positive tests are false positives. Unfortunately, many urgent care centers and emergency departments perform a rapid strep test prior to the treating practitioner spending 3-5 minutes doing a quick history and exam. Testing wastes resources in 40-50% of patients presenting with a sore throat complaint and leads to unnecessary antibiotics. This is the biggest mistake that I see!

The controversy for adolescents/adults with pharyngitis and Centor scores of 2-4 involves the concept of lack of proof. Why treat pharyngitis with antibiotics? 

There are 5 potential reasons to treat pharyngitis with antibiotics: 

  1. Prevent spread. Untreated group A strep and group C/G strep can lead to the spread of infection to those the patient come into contact with. We have no data for Fusobacterium necrophorum.
  2. Decrease duration of symptoms. In adults with scores of 3 or 4, Zwart et al (2000) found that both group A strep and group C/G strep had decreased symptom duration. Again we do not know for Fusobacterium necrophorum.
  3. Prevent non-suppurative complications. Antibiotics decrease the risk of acute rheumatic fever (ARF) for group A strep. We are not sure about group C/G strep (although it is likely since those bacteria can also cause ARF). We do not believe that Fusobacterium necrophorum causes any non-suppurative complications.
  4. Prevent suppurative complications. The Cochrane collaboration found that antibiotics decrease peritonsillar abscess regardless of pharyngitis etiology. My big concern is Lemierre syndrome. We have no PROOF that timely antibiotics will prevent the syndrome, but we must remember that lack of proof does not equal proof against that hypothesis. Many who study Fusobacterium necrophorum pharyngitis believe that appropriate antibiotics would decrease the probability of this severe complication. I believe Lemierre syndrome is the most important reason to treat adolescent/adult pharyngitis (Centor 2009).
  5. Prevent death from streptococcal shock syndrome. Very rare.

Therefore, I would give penicillin, amoxicillin, or clindamycin (if the patient has a true penicillin allergy) to adolescent/young adult patients with scores of 3 or 4 and some 2s (and use clinical judgment on how sick they look). Unpublished data suggest that tonsillar exudates are both a predictor of empiric antibiotics and significant infection.

Please, please never use macrolides for adolescent/adult pharyngitis. They do not cover Fusobacterium necrophorum. While we do not have full proof, a significant number of patients who develop the Lemierre syndrome received macrolides empirically. Macrolides are never the correct antibiotics for empiric treatment of adolescent/adult pharyngitis

Centor’s Corner is a Paging MDCalc column featuring our favorite pharyngitis guru, blogger extraordinaire, and Scientific Advisory Board member Dr. Robert Centor, with regular insights from Dr. Centor on the applications of evidence to practice and musings from an experienced clinician. To comment on Centor’s Corner articles, please e-mail the editor at rachel@mdcalc.com or tweet directly to Dr. Centor @medrants.