A 28-year-old woman from Delhi presents to the emergency department with acute onset sore throat, fever (39.2°C), and dysphagia for 2 days. On examination, she has exudative pharyngitis with enlarged tonsils, petechial rash on the soft palate, and cervical lymphadenopathy. A rapid antigen detection test (RADT) for group A Streptococcus is positive. She has no drug allergies. What is the most appropriate immediate next step in management?

Explanation

## Acute Streptococcal Pharyngitis: Management Algorithm **Key Point:** A positive RADT for group A Streptococcus (GAS) in a symptomatic patient with acute pharyngitis is sufficient to initiate antibiotic therapy without awaiting culture confirmation. **High-Yield:** The 2021 Infectious Diseases Society of America (IDSA) guidelines recommend immediate antibiotic initiation in RADT-positive acute pharyngitis to: - Reduce symptom duration by 24–48 hours - Prevent suppurative complications (peritonsillar abscess, retropharyngeal abscess) - Reduce the risk of acute rheumatic fever (ARF) when started within 9 days of symptom onset - Reduce transmission to household contacts ### Antibiotic Selection | Agent | Dose | Duration | Notes | |-------|------|----------|-------| | **Penicillin V** (first-line) | 500 mg QID | 10 days | Oral, standard therapy; excellent GAS coverage | | Amoxicillin | 500 mg TID | 10 days | Alternative oral; better taste than penicillin V | | Cephalexin | 500 mg QID | 10 days | For penicillin-allergic (non-anaphylaxis) | | Clindamycin | 300 mg TID | 10 days | For penicillin-allergic or macrolide resistance | | Azithromycin | 500 mg daily × 5 days | 5 days | Shorter course; NOT first-line (resistance rising) | **Clinical Pearl:** Penicillin V is the gold standard because GAS has never developed resistance to penicillin, and it is inexpensive and well-tolerated. **Warning:** Azithromycin monotherapy is no longer recommended as first-line due to rising macrolide resistance in GAS (up to 30% in some regions), though it remains an acceptable alternative if penicillin allergy is documented. ### Why Immediate Therapy? ```mermaid flowchart TD A[Acute pharyngitis + RADT positive for GAS]:::outcome --> B{Start antibiotics immediately?}:::decision B -->|Yes| C[Reduce ARF risk if started within 9 days]:::action B -->|Yes| D[Prevent suppurative complications]:::action B -->|Yes| E[Shorten symptom duration]:::action C --> F[Penicillin V 500 mg QID × 10 days]:::action D --> F E --> F F --> G[Clinical improvement expected in 24-48 hrs]:::outcome ``` **Mnemonic:** **RADT-TREAT** — RADT positive = Treat immediately, do not delay for culture.