What are the signs and symptoms of strep throat?

Signs and Symptoms of Strep Throat

Strep throat typically presents with sudden onset of severe sore throat, fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and notably the ABSENCE of cough—while viral pharyngitis is characterized by the presence of cough, rhinorrhea, and other upper respiratory symptoms. 1

Classic Bacterial (Streptococcal) Presentation

Cardinal Features

• Sudden onset of severe sore throat with pain on swallowing 1, 2
• High fever (typically >38°C or by history) 1
• Tonsillopharyngeal erythema with or without patchy exudates 1, 3, 4
• Tender, enlarged anterior cervical lymph nodes (lymphadenitis) 1, 3
• Notably ABSENT cough—this is a key distinguishing feature and part of the Centor criteria 1, 5

Additional Suggestive Findings

• Palatal petechiae ("doughnut lesions")—highly suggestive when present 1, 3
• Beefy red, swollen uvula 3
• Swollen tonsils with or without exudate 1, 4
• Scarlatiniform rash (sandpaper-like rash) 1
• Headache 1, 3, 4
• Nausea, vomiting, and abdominal pain (especially in children) 1, 3

Age and Seasonal Context

• Primarily affects children 5-15 years of age 1, 3
• More common in winter or early spring in temperate climates 1, 3
• History of exposure to documented strep throat increases likelihood 1, 3

Viral Pharyngitis Features (What Strep Throat is NOT)

Key Distinguishing Features

When these features are present, strep throat is UNLIKELY and testing is not indicated 1, 5:

• Cough (strongly suggests viral etiology) 1, 5, 6
• Nasal congestion or rhinorrhea (coryza) 1, 5, 3, 6
• Conjunctivitis 1, 3
• Hoarseness 1, 3, 6
• Diarrhea 1, 5
• Discrete oral ulcers (ulcerative stomatitis) 1, 3, 6
• Viral exanthem (characteristic viral rash) 1, 3

Clinical Decision Algorithm Using Modified Centor Criteria

The Four Core Criteria 1, 5:

1. Fever (by history or >38°C)
2. Tonsillar exudates
3. Tender anterior cervical adenopathy
4. ABSENCE of cough

Risk Stratification by Score 1:

• Score ≥4: 51-56% risk of strep throat
• Score 3: 28-35% risk
• Score 2: 11-17% risk
• Score 1: 5-10% risk
• Score ≤0: 1-2.5% risk

Management Based on Score 1, 5:

• <3 criteria: No testing needed—likely viral
• ≥3 criteria: Perform rapid antigen detection test (RADT) or throat culture
• Positive RADT: Diagnostic for strep throat
• Negative RADT in children/adolescents: Backup throat culture recommended 1, 6
• Negative RADT in adults: Backup culture generally not necessary (low incidence and rheumatic fever risk) 1, 6

Critical Diagnostic Pitfalls

Common Mistakes to Avoid

• Clinical features alone cannot definitively diagnose strep throat—even experienced clinicians cannot reliably distinguish bacterial from viral pharyngitis without laboratory confirmation 1, 3
• Only 20-30% of patients present with "classic" disease—physicians significantly overdiagnose strep throat clinically, leading to unnecessary antibiotic use 4
• Do NOT test patients with obvious viral features (cough, rhinorrhea, conjunctivitis)—this leads to false positives and inappropriate antibiotic prescribing 1, 5
• Tonsillar exudates are NOT specific for strep throat—they can occur with viral infections, particularly Epstein-Barr virus (mononucleosis) 7

Red Flags Requiring Urgent Evaluation 1:

Patients with these features need evaluation for serious complications:

• Difficulty swallowing or drooling
• Neck tenderness or swelling
• Unusually severe symptoms
• Consider peritonsillar abscess, parapharyngeal abscess, epiglottitis, or Lemierre syndrome

Age-Specific Considerations

Children <3 Years 1, 3:

• Classic findings may be less apparent
• Infants may present with excoriated nares or purulent nasal discharge rather than typical pharyngitis
• Testing generally not recommended unless specific risk factors present

Adolescents and Young Adults 1:

• Consider Fusobacterium necrophorum (implicated in 10-20% of endemic pharyngitis)
• Remain vigilant for Lemierre syndrome in patients with severe pharyngitis
• Higher risk for complications if untreated

Diagnostic Accuracy of Individual Findings 7:

Most Useful Positive Findings (Likelihood Ratios):

• Tonsillar exudate: 3.4
• Pharyngeal exudate: 2.1
• Exposure to strep in previous 2 weeks: 1.9

Most Useful Negative Findings (Likelihood Ratios):

• Absence of tender anterior cervical nodes: 0.60
• Absence of tonsillar enlargement: 0.63
• Absence of exudate: 0.74

No single finding is sufficiently accurate to rule in or rule out strep throat—use validated clinical prediction rules and laboratory confirmation. 7