Distinguishing viral and bacterial causes of pharyngitis on the basis of history and physical examination alone is difficult. However, cough is not usually associated with GAS infection. Pharyngitis after several days of coughing or rhinorrhea is more consistent with a viral etiology. Headache and sudden onset are consistent with GAS infection, and vomiting is associated with various types.
In addition, these factors may help rule out or diagnose GAS pharyngitis:
Contact with others who have GAS or rheumatic fever with symptoms consistent with GAS raises the likelihood of GAS pharyngitis.
Recent orogenital contact suggests possible gonococcal pharyngitis.
A history of rheumatic fever is important.
Centor criteria for GAS pharyngitis allocate one point for each of these:
Anterior cervical lymphadenopathy
Absence of cough
A GAS infection is unlikely with a score of 0-1; a score of 4 makes it likely. The positive predictive value of these criteria is around 40% if three criteria are met in adults; this jumps to about 50% if four criteria are met.
Learn more about pharyngitis.
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Cite this: Richard H. Sinert. Fast Five Quiz: Pharyngitis (Sore Throat) - Medscape - Dec 14, 2022.