What is the most likely diagnosis and recommended management for a patient with white‑plaque‑covered tonsils, cough, and sore throat, with negative rapid tests for respiratory syncytial virus, Group A streptococcus, and SARS‑CoV‑2?

White Plaque Tonsils with Cough and Negative Testing: Diagnosis and Management

This presentation is almost certainly viral pharyngitis, and antibiotics should be withheld entirely. The presence of cough is a key distinguishing feature that strongly points away from bacterial causes toward viral infection, and the negative strep test effectively rules out Group A streptococcal pharyngitis 1, 2.

Most Likely Diagnosis: Viral Pharyngitis

The combination of cough with negative RSV, strep, and COVID testing makes viral pharyngitis from another common respiratory virus the overwhelming diagnosis. The presence of cough is particularly important because it is strongly associated with viral rather than bacterial pharyngitis 1, 3, 4.

Common Viral Causes to Consider:

• Rhinovirus is the most frequent cause of acute pharyngitis and commonly presents with cough and sore throat 5, 2
• Adenovirus frequently causes pharyngitis with tonsillar exudates (white plaques) and can mimic bacterial infection 5, 6
• Coronavirus (non-COVID strains) commonly causes pharyngitis with mild respiratory symptoms 2
• Parainfluenza virus, Influenza virus, and Enteroviruses are other potential causes 5
• Epstein-Barr virus (infectious mononucleosis) should be considered if severe pharyngitis with tonsillar exudate persists, though this typically presents with more systemic symptoms 5

Critical Point About White Plaques/Exudates

White patches and tonsillar exudates occur commonly with viral infections and do not reliably distinguish bacterial from viral causes. Clinicians consistently overestimate the probability of bacterial infection based on appearance alone 6, 7. The presence of exudates overlaps too broadly between bacterial and viral etiologies to make accurate clinical diagnosis without laboratory confirmation 6.

Why the Negative Strep Test is Definitive

• Rapid antigen detection tests have ≥95% specificity, making false-positive results rare 1
• In adults, a negative RADT alone is sufficient to rule out Group A streptococcal pharyngitis without requiring backup throat culture 1, 6
• This differs from children and adolescents, where backup throat culture is recommended because RADT sensitivity is only 80-90% 1
• The sensitivity limitation (80-90%) is acceptable in adults because of the extremely low incidence of streptococcal infection (5-10%) and virtually zero risk of acute rheumatic fever 6

Recommended Management Algorithm

Immediate Actions:

1. Withhold antibiotics entirely – up to 70% of patients with sore throats receive unnecessary antibiotic prescriptions, while only 20-30% actually have bacterial pharyngitis 5, 6
2. Provide symptomatic relief:
   • NSAIDs (ibuprofen or naproxen) or acetaminophen for pain and fever control 6, 2
   • Throat lozenges for comfort 5, 2
3. Reassure the patient that viral pharyngitis typically resolves in less than 1 week 5, 2

Patient Education:

• Explain that antibiotics provide no benefit for viral infections and carry risk of adverse effects 6
• Antibiotics shorten bacterial sore throat duration by only 1-2 days even when indicated 6
• The white plaques will resolve on their own as the viral infection clears 6

Red Flags Requiring Urgent Reassessment

Return immediately or call if any of the following develop:

• Development of fever (if currently afebrile) 5, 2
• Difficulty swallowing or breathing 5, 2
• Severe unilateral throat pain with trismus (suggests peritonsillar abscess) 2
• Neck swelling, tenderness, or painful swollen neck (raises concern for Lemierre syndrome) 2
• Worsening symptoms after 3-5 days or symptoms persisting beyond 7-10 days 5, 6

Common Pitfalls to Avoid

Do NOT:

• Prescribe antibiotics based on the appearance of white plaques alone – this leads to massive antibiotic overuse without clinical benefit 5, 6
• Order a backup throat culture in adults with negative RADT – this is not indicated and wastes resources 1, 6
• Test or treat asymptomatic household contacts – up to one-third of household members may be asymptomatic carriers, and prophylactic treatment does not reduce subsequent infection rates 1, 6
• Assume all tonsillar exudates are bacterial – viral infections frequently produce identical-appearing exudates 6, 7

Special Consideration:

If symptoms persist beyond 7-10 days or worsen significantly, consider testing for Epstein-Barr virus (infectious mononucleosis), which commonly presents with severe pharyngitis, tonsillar exudate, and white patches 6. However, most viral pharyngitis resolves well before this timeframe 5, 2.