What is the most likely diagnosis and recommended management for a patient with a scratchy throat and pharyngeal inflammation extending beyond the tonsils, in the absence of red‑flag symptoms?

Scratchy Throat with Pharyngeal Inflammation Beyond the Tonsils

This presentation most likely represents viral pharyngitis, and you should withhold antibiotics and provide symptomatic care only unless microbiologic testing confirms Group A streptococcus (GAS). 1, 2

Differential Diagnosis

The key distinction is whether this is bacterial (requiring antibiotics) or viral (self-limited):

• Viral pharyngitis accounts for 70–95% of acute pharyngitis cases and causes diffuse pharyngeal inflammation that commonly extends beyond the tonsillar pillars 3, 4
• Group A β-hemolytic streptococcus (GAS) causes only 10% of adult pharyngitis but is the primary bacterial pathogen requiring treatment 2, 5
• Groups C and G streptococci produce identical clinical pictures to GAS and should be treated identically if confirmed 2
• Epstein-Barr virus (infectious mononucleosis) frequently causes exudative pharyngitis with generalized lymphadenopathy and splenomegaly 2
• Adenovirus and other respiratory viruses (parainfluenza, RSV) can cause pharyngeal inflammation extending beyond the tonsils 2

Clinical Assessment Using Modified Centor Criteria

Calculate the Centor score to determine testing strategy 2, 5:

• Fever (temperature >38°C): +1 point 1
• Tonsillar exudates: +1 point 1
• Tender anterior cervical lymphadenopathy: +1 point 1, 2
• Absence of cough: +1 point 1, 2

Clinical features strongly suggesting viral etiology (do NOT test or treat):

• Cough, coryza (runny nose), hoarseness, conjunctivitis, or diarrhea 1, 3
• Gradual onset of symptoms 3
• Oral ulcers or viral exanthem 3

Management Algorithm Based on Centor Score

Centor Score	Action
0–1 points	No testing or antibiotics needed; provide symptomatic care only [2,6]
2–3 points	Perform rapid antigen detection test (RADT) or throat culture; treat only if positive [2,5]
≥4 points	Either obtain confirmatory testing OR consider empiric antibiotics [2]

Critical point: Never start antibiotics based on clinical impression alone without microbiologic confirmation, as this leads to massive overtreatment 6

Diagnostic Testing When Indicated

• Rapid antigen detection test (RADT) has >95% specificity but variable sensitivity 2
• In children and adolescents: A negative RADT must be confirmed with throat culture because of rheumatic fever risk 2, 6
• In adults: A negative RADT may be accepted without backup culture because rheumatic fever risk is low 2
• Throat culture remains the gold standard with 90–95% sensitivity when performed correctly (vigorous swabbing of both tonsils and posterior pharynx) 2, 7

Antibiotic Treatment for Confirmed GAS (If Testing Positive)

First-line for non-penicillin-allergic patients:

• Amoxicillin 500 mg PO twice daily for 10 days (preferred) 2, 6
• Penicillin V 500 mg PO twice daily for 10 days (acceptable alternative) 2, 6
• Benzathine penicillin G 1,200,000 U IM single dose (for patients ≥27 kg; preferred when compliance is questionable) 2, 6

For penicillin-allergic patients:

• Non-anaphylactic/delayed reactions: First-generation cephalosporins (e.g., cephalexin 500 mg PO twice daily for 10 days); cross-reactivity is only ≈0.1% 2
• Immediate or anaphylactic reactions: Clindamycin 300 mg PO three times daily for 10 days (preferred; only ~1% resistance) 2
• Alternative for penicillin allergy: Azithromycin 500 mg PO once daily for 5 days (acceptable but resistance is rising to 5–8%) 2, 8

Complete the full 10-day course to achieve pharyngeal eradication and prevent acute rheumatic fever 2, 6

Symptomatic Care (For All Patients)

• Ibuprofen or acetaminophen for fever and throat pain 2, 3, 6
• Warm salt water gargles for throat discomfort 3, 6
• Adequate hydration and rest 3
• Expected improvement timeline: 3–7 days 3

Critical Pitfalls to Avoid

• Do NOT use cephalosporins in patients with immediate/anaphylactic penicillin reactions (≈10% cross-reactivity risk) 2
• Do NOT prescribe antibiotics for viral pharyngitis; they provide no benefit and may cause harm 3
• Do NOT shorten therapy below 10 days (except the 5-day azithromycin regimen) 2
• Avoid aspirin in children because of Reye syndrome risk 2, 3
• Avoid amoxicillin or ampicillin if infectious mononucleosis is suspected; a maculopapular rash occurs in 80–100% of such patients 2
• Do NOT perform follow-up throat cultures on asymptomatic patients who completed appropriate therapy 1, 6

Special Considerations

• Children younger than 3 years have very low incidence of GAS and acute rheumatic fever; routine testing/treatment is unnecessary 2
• Asymptomatic household contacts do not require testing or prophylactic antibiotics 2
• Chronic GAS carriers with intercurrent viral infections test positive but do not require antibiotic treatment 3, 6