Differential Diagnosis for Sore Throat with Negative Strep Testing
This 11-year-old most likely has viral pharyngitis and requires only symptomatic treatment with analgesics such as ibuprofen or acetaminophen, with no antibiotics indicated. 1
Most Likely Diagnosis: Viral Pharyngitis
The absence of fever, systemic symptoms, and negative strep testing strongly points toward a viral etiology. 2 The clinical presentation lacks the typical features of Group A Streptococcal (GAS) pharyngitis, which usually includes:
- Sudden-onset severe sore throat
- Fever (typically 101°F-104°F)
- Tonsillopharyngeal exudates
- Tender anterior cervical lymphadenopathy
- Absence of viral features 2
Comprehensive Differential Diagnosis List
Viral Causes (Most Common)
- Rhinovirus - the most frequent cause of acute pharyngitis 2
- Adenovirus - commonly causes pharyngitis without systemic symptoms 2
- Parainfluenza virus 2
- Coronavirus 2
- Respiratory syncytial virus 2
- Influenza virus 2
- Epstein-Barr virus (infectious mononucleosis) - though typically presents with generalized lymphadenopathy and splenomegaly 2
- Enteroviruses (coxsackievirus, ECHO viruses) 2
- Herpes simplex virus 2
Bacterial Causes (Less Likely Given Negative Testing)
- Groups C and G β-hemolytic streptococci - can cause pharyngitis similar to GAS but not associated with rheumatic fever 2
- Arcanobacterium haemolyticum - particularly in teenagers and young adults, often with scarlatiniform rash 2, 3
- Mycoplasma pneumoniae - uncommon cause 2
- Chlamydia pneumoniae - uncommon cause 2
Other Considerations
- Allergic pharyngitis - environmental allergens causing throat irritation 4
- Irritant exposure - dry air, pollutants, or mouth breathing 4
- Gastroesophageal reflux - can cause chronic throat irritation 4
Important Clinical Caveat About Negative Strep Testing
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. 2, 1 The sensitivity of RADTs is only 70-90% compared to throat culture, meaning they miss 10-20% of true strep infections. 2, 1 However, if a backup throat culture was not sent and the clinical presentation strongly suggests viral etiology (as in this case), symptomatic treatment is appropriate. 1
Recommended Management Approach
Immediate Management
- Withhold antibiotics - up to 70% of patients with sore throats receive unnecessary antibiotic prescriptions, while only 20-30% actually have GAS pharyngitis 1
- Provide symptomatic relief with ibuprofen or acetaminophen 1
- Throat lozenges for comfort 1
- Reassurance that viral pharyngitis typically resolves in less than 1 week 1
If Backup Culture Was Sent
- If the throat culture returns positive for GAS, antibiotics can be initiated at that time 1
- Treatment within 9 days of symptom onset still effectively prevents acute rheumatic fever 1
Red Flags Requiring Reassessment
- Development of fever, difficulty swallowing, or systemic symptoms 2
- Worsening symptoms after 3-5 days 4
- Development of respiratory distress or stridor (suggests epiglottitis or other serious condition) 5
Key Pitfall to Avoid
Do not treat based on clinical symptoms alone without laboratory confirmation, as this leads to antibiotic overuse without clinical benefit and increases the risk of adverse effects. 1 The specificity of RADT is ≥95%, making false positives rare, so a negative test is highly reliable for ruling out GAS in the appropriate clinical context. 1