The Incorrect Statement is C
Statement C is INCORRECT: Streptococcal pharyngitis CAN cause a rash, most notably scarlet fever, which is a characteristic complication of Group A Streptococcus (GAS) pharyngitis.
Analysis of Each Statement
Statement A - CORRECT
Streptococcus pyogenes (Group A Streptococcus) is indeed the most common bacterial cause of pharyngitis 1, 2. While only 10% of adults with sore throat have GAS pharyngitis, it remains the predominant bacterial etiology when bacterial infection is present 2.
Statement B - CORRECT
Centor criteria are widely used in clinical practice to assess the probability of GAS pharyngitis. The criteria include fever, tonsillar exudate, cervical lymphadenitis, and absence of cough, with patient age being an important modifier (ages 3-15 years increase suspicion) 2.
Statement C - INCORRECT (The Answer)
This statement is false because streptococcal pharyngitis commonly causes rash in the form of scarlet fever. The IDSA guidelines explicitly mention that Arcanobacterium haemolyticum can cause "a rash similar to that seen in scarlet fever" 1, directly acknowledging that scarlet fever (a sandpaper-like rash) is a well-recognized manifestation of GAS pharyngitis. The statement incorrectly suggests that only viral pharyngitis causes rashes.
Statement D - CORRECT
EBV and HIV are appropriately included in the differential diagnosis. The IDSA guidelines note that multiple viral agents including cytomegalovirus and other viruses can cause acute pharyngitis 1, and these must be distinguished from GAS pharyngitis, particularly when clinical presentation is atypical.
Statement E - CORRECT
Amoxicillin is a first-line antibiotic for GAS pharyngitis, along with penicillin 2, 3. Both narrow-spectrum penicillins (penicillin V and amoxicillin) are recommended as first-line therapy with a 10-day course 2. Recent network meta-analysis confirms penicillin should remain the preferred first-line therapy 4.
Clinical Pitfall to Avoid
Do not assume that the presence of a rash excludes streptococcal pharyngitis. Scarlet fever represents GAS pharyngitis with an erythrogenic toxin-producing strain, presenting with the classic sandpaper-textured erythematous rash, strawberry tongue, and circumoral pallor—all occurring with bacterial (not just viral) pharyngitis.