Differential Diagnosis for Sore Throat with Negative Strep Testing

Most Likely Diagnosis: Viral Pharyngitis

The American Heart Association suggests that the absence of fever, systemic symptoms, and negative strep testing strongly points toward a viral etiology, characterized by the lack of typical features of Group A Streptococcal (GAS) pharyngitis, which usually includes sudden-onset severe sore throat, fever, tonsillopharyngeal exudates, and tender anterior cervical lymphadenopathy 2, 3, 4, 5
The clinical presentation of viral pharyngitis often lacks the typical features of GAS pharyngitis, such as sudden-onset severe sore throat, fever, tonsillopharyngeal exudates, and tender anterior cervical lymphadenopathy, with a strength of evidence supporting viral etiology as the most likely diagnosis 2, 3, 5

The Infectious Diseases Society of America recommends considering Rhinovirus as the most frequent cause of acute pharyngitis, with Adenovirus, Parainfluenza virus, Coronavirus, Respiratory syncytial virus, Influenza virus, Epstein-Barr virus, Enteroviruses, and Herpes simplex virus as other potential viral causes 2, 5
The Centers for Disease Control and Prevention suggest that Adenovirus commonly causes pharyngitis without systemic symptoms, similar to other viral causes 2, 5

The American Academy of Pediatrics notes that Groups C and G β-hemolytic streptococci can cause pharyngitis similar to GAS but are not associated with rheumatic fever, with Arcanobacterium haemolyticum, Mycoplasma pneumoniae, and Chlamydia pneumoniae as less common bacterial causes 2, 5

The Clinical Infectious Diseases society recommends that in children and adolescents, a negative rapid antigen detection test (RADT) should ideally be confirmed with a throat culture before definitively ruling out GAS pharyngitis, due to the sensitivity of RADTs being only 70-90% compared to throat culture 6, 7, 1

The American College of Physicians advises withholding antibiotics, as up to 70% of patients with sore throats receive unnecessary antibiotic prescriptions, while only 20-30% actually have GAS pharyngitis, and providing symptomatic relief with ibuprofen or acetaminophen 1
The American Academy of Family Physicians recommends providing throat lozenges for comfort and reassurance that viral pharyngitis typically resolves in less than 1 week 1

The Infectious Diseases Society of America suggests that if the throat culture returns positive for GAS, antibiotics can be initiated at that time, with treatment within 9 days of symptom onset still effectively preventing acute rheumatic fever 1

The American Heart Association notes that development of fever, difficulty swallowing, or systemic symptoms, as well as worsening symptoms after 3-5 days, or development of respiratory distress or stridor, are red flags requiring reassessment 3, 8

The Centers for Disease Control and Prevention warn against treating based on clinical symptoms alone without laboratory confirmation, as this leads to antibiotic overuse without clinical benefit and increases the risk of adverse effects, with the specificity of RADT being ≥95%, making false positives rare 1