Streptococcal Pharyngitis ('Strep Throat')

ENT / Infectious Disease

Overview

Definition

An acute infection of the pharynx and palatine tonsils caused by Group A Streptococcus.

Epidemiology

Most common in children ages 5-15, particularly during winter and early spring.

Etiology & Risk Factors

  • Group A beta-hemolytic Streptococcus (Streptococcus pyogenes)

Clinical Symptoms

  • Sudden onset of severe sore throat and odynophagia (painful swallowing)
  • Fever
  • Tonsillar exudates (white/yellow patches on red, swollen tonsils)
  • Tender anterior cervical lymphadenopathy
  • ABSENCE of cough (viral pharyngitis usually has cough, rhinorrhea, and conjunctivitis)

Clinical Approach

Diagnosis

  • Centor Criteria (Fever, Exudates, Tender anterior cervical adenopathy, NO cough): Used to risk-stratify
  • Rapid Antigen Detection Test (RADT): Initial test of choice
  • Throat Culture: Gold Standard (performed if RADT is negative in children/adolescents to avoid missing the diagnosis)

Management

  • Penicillin V (oral) or Amoxicillin for 10 days
  • Cephalexin or Azithromycin for Penicillin-allergic patients
  • Goal of treatment: Accelerate symptom resolution AND prevent Acute Rheumatic Fever

Complications

  • Acute Rheumatic Fever (molecular mimicry affecting the heart valves, prevented by antibiotics)
  • Post-Streptococcal Glomerulonephritis (PSGN - NOT prevented by antibiotics)
  • Peritonsillar Abscess (Quinsy)