A 28-year-old woman from rural Maharashtra presents with a 3-day history of severe sore throat, fever (39.5°C), and difficulty swallowing. On examination, she has exudative pharyngitis with enlarged tonsils, petechial rash on the soft palate, and tender cervical lymphadenopathy. A rapid antigen detection test (RADT) is positive. She has no penicillin allergy. Which of the following is the most appropriate immediate management?

Explanation

## Streptococcus pyogenes Pharyngitis: First-Line Treatment **Key Point:** Penicillin V (oral) or penicillin G (IM) remains the gold-standard first-line therapy for Group A Streptococcus (GAS) pharyngitis, with a 10-day course required to eradicate the organism and prevent suppurative and non-suppurative sequelae. ### Clinical Presentation Recognition This patient has classic acute streptococcal pharyngitis: - Exudative pharyngitis with tonsillar enlargement - Petechial rash on soft palate (pathognomonic for GAS) - Tender cervical lymphadenopathy - Positive RADT (high specificity for GAS) ### Treatment Algorithm ```mermaid flowchart TD A[Acute pharyngitis + RADT positive]:::outcome --> B{Penicillin allergy?}:::decision B -->|No allergy| C[Penicillin V 250 mg QID x 10 days]:::action B -->|Non-severe allergy| D[Cephalosporin 1st/2nd gen]:::action B -->|Severe allergy| E[Azithromycin or clindamycin]:::action C --> F[Prevents rheumatic fever & suppurative complications]:::outcome D --> F E --> F ``` ### Why Penicillin V (Oral) Is Preferred Here | Feature | Penicillin V | Cephalosporin | Azithromycin | |---------|-------------|---------------|---------------| | **First-line status** | Yes (gold standard) | Second-line (allergy only) | Third-line (allergy/resistance) | | **Dosing** | 250 mg QID × 10 days | 1 g IV/IM (overkill for uncomplicated pharyngitis) | 5-day course (shorter, but inferior efficacy) | | **Cost** | Lowest | Higher | Moderate | | **GAS resistance** | Rare (<1%) | Rare | Increasing (10–15% in some regions) | | **Indication** | First choice, no allergy | Mild penicillin allergy | Allergy or intolerance | **High-Yield:** The 10-day duration is non-negotiable — shorter courses (even 5 days) fail to prevent acute rheumatic fever (ARF), which occurs in 3% of untreated cases and 0.5% of inadequately treated cases. **Clinical Pearl:** Cephalosporins (option A) are reserved for penicillin-allergic patients with non-severe (non-IgE-mediated) allergy; cross-reactivity is <2%. They are NOT first-line and represent overtreatment in a patient with no allergy. **Warning:** Azithromycin (option C), while acceptable in allergy, is inferior to penicillin for GAS and carries a higher failure rate due to emerging resistance. It should not be used as first-line in non-allergic patients. ## Rationale for Rejecting Other Options - **Option A (Cephalosporin IV):** Unnecessarily escalated; reserved for penicillin allergy or severe invasive disease (e.g., necrotizing fasciitis). Oral dosing is also more practical for uncomplicated pharyngitis. - **Option C (Azithromycin):** Inferior to penicillin; higher failure rates and emerging resistance. Only used if penicillin allergy. - **Option D (Supportive care alone):** Risks suppurative complications (abscess, epiglottitis) and non-suppurative sequelae (ARF, post-streptococcal glomerulonephritis). RADT-positive cases mandate antibiotic therapy. **Mnemonic — GAS Complications (RASH):** Rheumatic fever, Abscess (peritonsillar), Scarlet fever, Hemolytic uremic syndrome / post-streptococcal glomerulonephritis — all prevented by timely penicillin.