What are the probable diagnoses for a patient presenting with a sore throat and fever for 3 days?

Probable Diagnoses for Sore Throat and Fever for 3 Days

The most likely diagnosis is viral pharyngitis, which accounts for the vast majority of acute sore throat cases and typically resolves spontaneously within 7-10 days, though bacterial pharyngitis from Group A Streptococcus must be ruled out using clinical scoring systems. 1, 2

Primary Differential Diagnoses

Viral Pharyngitis (Most Common)

• Accounts for 65-85% of all acute pharyngitis cases in adults and the majority in children 1
• Common viral causes include:
  • Rhinovirus and coronavirus (common cold viruses) 1
  • Adenovirus 1
  • Influenza and parainfluenza 1
  • Epstein-Barr virus (infectious mononucleosis) 1
  • Herpes simplex virus 1, 3
  • Coxsackie A virus (herpangina) 3
• Typical duration is 7-10 days with symptoms improving after 3-4 days 2, 4
• Associated features suggesting viral etiology include cough, nasal congestion, conjunctivitis, hoarseness, diarrhea, or oropharyngeal lesions (ulcers/vesicles) 1

Group A Streptococcal (GAS) Pharyngitis

• Causes 15-30% of pharyngitis in children and only 5-15% in adults 5
• More common in late winter and early spring 5
• Key clinical features include:
  • Fever (temperature >38°C/100.4°F) 5, 6
  • Tonsillar exudates 5, 6
  • Tender anterior cervical adenopathy 5, 6
  • Absence of cough (critical distinguishing feature) 1, 5
  • Swollen tonsils and palatal petechiae 1
  • Scarlatiniform rash in some cases 3
• Without treatment, fever and constitutional symptoms resolve spontaneously in 3-4 days 4

Clinical Decision-Making Algorithm

Step 1: Apply Modified Centor Criteria

Calculate score based on:

• Fever by history (1 point) 1
• Tonsillar exudates (1 point) 1
• Tender anterior cervical adenopathy (1 point) 1
• Absence of cough (1 point) 1

Interpretation:

• 0-2 points: Viral pharyngitis most likely - no testing or antibiotics needed 1, 7
• 3 points: Consider testing with rapid antigen detection test 1, 7
• 4 points: Test or treat empirically for streptococcal infection 1, 7

Step 2: Testing Strategy (If Indicated)

• Rapid antigen detection test (RADT) is first-line for patients with ≥3 Centor criteria 1, 7
• If RADT is negative, throat culture is not necessary in adults 7
• Do not test patients with clear viral symptoms (cough, congestion, conjunctivitis) 1

Less Common But Important Diagnoses to Consider

Infectious Mononucleosis (EBV)

• Presents with sore throat, fever, and generalized lymphadenopathy and splenomegaly 3
• More common in adolescents and young adults 1

Other Bacterial Causes

• Fusobacterium necrophorum: Implicated in 10-20% of endemic pharyngitis in adolescents 1
• Neisseria gonorrhoeae: Consider in sexually active patients with appropriate risk factors 3
• Corynebacterium diphtheriae: Rare, but suggested by typical membrane 3
• Corynebacterium haemolyticum: May present with scarlatiniform rash 3

Serious Conditions Requiring Urgent Evaluation

Red flags indicating need for immediate assessment:

• Difficulty swallowing or drooling 1
• Neck tenderness or swelling 1
• Severe unilateral throat pain (peritonsillar abscess) 1, 3
• Cherry-red epiglottis (epiglottitis from H. influenzae type b) 3
• Respiratory distress 1

Non-Infectious Causes (Rare)

• Thyroiditis 3
• Candidal infection (consider HIV if present) 3

Management Approach

For Viral Pharyngitis (Most Cases)

• Symptomatic treatment is the cornerstone 2
• NSAIDs (ibuprofen or naproxen) are more effective than acetaminophen for pain and fever 2, 5
• Throat lozenges, salt water gargles, and topical anesthetics provide temporary relief 2
• No antibiotics indicated 1, 2

For Confirmed Streptococcal Pharyngitis

• Penicillin V or amoxicillin for 10 days is first-line treatment 1, 7, 6
• Antibiotics shorten symptom duration by only 1-2 days 2, 4
• First-generation cephalosporins or macrolides for penicillin-allergic patients 1, 6

Common Pitfalls to Avoid

• Do not prescribe antibiotics for viral pharyngitis - increases resistance and adverse effects without benefit 1, 2
• Do not test patients with <3 Centor criteria - low positive predictive value wastes resources 1
• Do not assume all sore throats are streptococcal - most are viral and self-limited 4
• Do not miss severe presentations requiring urgent intervention (peritonsillar abscess, epiglottitis, Lemierre syndrome) 1
• Do not use broad-spectrum antibiotics (like amoxicillin-clavulanate or azithromycin) as first-line therapy - increases resistance without additional benefit 7