What test should I perform to diagnose a patient with suspected viral pharyngitis presenting with jaw pain and swollen glands?

Diagnostic Testing for Viral Pharyngitis with Jaw Pain and Swollen Glands

For a patient with suspected viral pharyngitis presenting with jaw pain and swollen glands radiating under the right ear, a throat swab for rapid antigen detection testing (RADT) should be performed to rule out Group A Streptococcal (GAS) infection, with no need for backup culture if negative in adults. 1

Initial Assessment

• Clinical features of viral pharyngitis include jaw pain, swollen glands (lymphadenopathy), and often accompanying symptoms such as coryza (nasal discharge), cough, hoarseness, and possibly oral ulcers 2
• The presence of rhinorrhea, cough, hoarseness, and oral ulcers strongly suggests viral etiology rather than bacterial infection 1
• Swollen glands radiating under the ear (cervical lymphadenopathy) can occur with both viral and bacterial pharyngitis, but the pattern and associated symptoms help differentiate 2

Diagnostic Algorithm

Step 1: Clinical Evaluation

• Assess for features suggesting viral etiology:
  • Presence of cough, rhinorrhea, hoarseness, or oral ulcers strongly suggests viral cause 1
  • Absence of high fever, tonsillar exudates, or palatal petechiae makes viral etiology more likely 2

Step 2: Laboratory Testing

• Perform rapid antigen detection test (RADT) to rule out Group A Streptococcal infection 1
  • If RADT is negative in adults, no backup throat culture is necessary due to low incidence of GAS pharyngitis in adults 1
  • If RADT is negative in children/adolescents, a backup throat culture should be performed 1

Step 3: Additional Testing (if indicated)

• If mononucleosis is suspected (prolonged symptoms, significant fatigue, generalized lymphadenopathy), consider Monospot test or EBV-specific antibody testing 1
• For persistent symptoms or atypical presentation, consider throat swab for viral PCR panel to identify specific viral pathogens 1

Specific Testing Recommendations

• Primary test: Throat swab for RADT to rule out streptococcal infection 1
• For children: If RADT is negative, follow with throat culture 1
• For adults: Backup culture after negative RADT is not routinely necessary 1

Clinical Pearls and Pitfalls

• Viral pharyngitis is the most common cause of sore throat, accounting for 85-95% of cases in adults 1, 3
• The clinical presentation alone cannot definitively distinguish between viral and bacterial pharyngitis, making laboratory confirmation important 1
• Treating only confirmed cases of streptococcal pharyngitis helps prevent antibiotic resistance 1
• Jaw pain with lymphadenopathy radiating under the ear is consistent with inflammation of the tonsillar lymph nodes, common in viral infections 2, 3
• Unnecessary antibiotic use for viral pharyngitis contributes to antimicrobial resistance and should be avoided 1

Special Considerations

• In patients with recurrent symptoms, consider testing for less common causes or chronic viral infections 1
• If symptoms persist beyond 7-10 days or worsen after initial improvement, additional evaluation may be warranted 3, 4
• For patients with high risk of complications (immunocompromised, history of rheumatic fever), a lower threshold for testing and treatment may be appropriate 1