Guideline‑Recommended Management of Treatment‑Failure Group A Streptococcal Tonsillitis

1. Why Cephalexin Is Inappropriate

The Infectious Diseases Society of America (IDSA) does not recommend cephalexin for streptococcal pharyngitis; instead it endorses cefadroxil as the first‑generation cephalosporin of choice, with a strong recommendation based on high‑quality evidence for a 10‑day course at 30 mg/kg once daily. 1

Persistent throat pain, purulent drainage, and systemic chills after 3 days of therapy indicate treatment failure and ongoing bacterial infection, warranting a change in antibiotic. 3

Amoxicillin 50 mg/kg/day divided twice daily (maximum 500 mg twice daily or 1000 mg once daily) for a full 10‑day course is the IDSA first‑line regimen for Group A streptococcal tonsillitis, supported by strong evidence. 2
In patients with a suspected penicillin allergy, cefadroxil 30 mg/kg once daily (maximum 1 g) for 10 days is the recommended alternative, endorsed by the IDSA with a strong recommendation. 1

A mandatory 10‑day antibiotic course is essential; shorter courses (e.g., 5 days) are associated with markedly higher recurrence rates (≈ 27 % vs 6 % within 1 week; ≈ 55 % vs 24 % within 2 months) and do not prevent acute rheumatic fever. 1
Once‑daily or twice‑daily amoxicillin dosing (50 mg/kg once daily or 25 mg/kg twice daily) provides equivalent efficacy to more frequent regimens and improves patient adherence compared with four‑times‑daily cephalexin. 2

Evaluate for peritonsillar abscess (quinsy) when purulent drainage, persistent pain, and systemic symptoms are present; look for unilateral tonsillar swelling, uvular deviation, trismus, or “hot‑potato” voice. 3
Recognize that quinsy is often polymicrobial, with Group A streptococcus as the predominant pathogen, which may explain failure of narrow‑spectrum agents such as cephalexin. 3

Immediate referral for drainage is required when a peritonsillar abscess is suspected, in addition to appropriate antibiotic therapy. 3

If symptoms persist after 48–72 hours of appropriate first‑line therapy, obtain an ENT consultation to assess for complications or infection with other streptococcal groups (e.g., Group C or G). 3

Do not continue cephalexin after documented treatment failure, as it lacks FDA endorsement for streptococcal pharyngitis and is ineffective in this context. 3
Do not attribute purulent tonsillitis with systemic signs to a viral etiology; bacterial infection (primarily Group A streptococcus) is the likely cause. 3