What is the recommended treatment for streptococcal (strep) infection in an adult male with a hypersensitivity to penicillin (PCN)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 29, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

For an adult male with a penicillin allergy, the most appropriate treatment for strep throat is azithromycin 12 mg/kg once daily (max = 500 mg) for 5 days, as recommended by the Infectious Diseases Society of America 1. When considering treatment options for strep throat in patients with penicillin allergies, it's crucial to choose an antibiotic that is effective against Group A Streptococcus (GAS) and has a strong recommendation based on high-quality evidence.

  • The guidelines from the Infectious Diseases Society of America 1 provide recommendations for antibiotic regimens in patients with penicillin allergies, including azithromycin, clarithromycin, and clindamycin.
  • Azithromycin is a preferred option due to its once-daily dosing and shorter treatment duration of 5 days, which can improve patient compliance.
  • It's essential to note that cephalosporins, such as cephalexin, should be avoided in patients with immediate-type hypersensitivity to penicillin, as they may cross-react 1.
  • Completing the full course of antibiotics is vital to prevent complications like rheumatic fever or kidney inflammation, even if symptoms improve.
  • Supportive care, including pain and fever management with acetaminophen or ibuprofen, warm salt water gargles, and adequate hydration, is also recommended to help alleviate symptoms.

From the FDA Drug Label

Pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy. NOTE: Penicillin by the intramuscular route is the usual drug of choice in the treatment of Streptococcus pyogenes infection and the prophylaxis of rheumatic fever. Azithromycin is often effective in the eradication of susceptible strains of Streptococcus pyogenes from the nasopharynx In cases of β-hemolytic streptococcal infections, treatment should continue for at least 10 days.

Treating strep in an adult male with an allergy to penicillin can be done with azithromycin (PO) 2 or clindamycin (PO) 3 as an alternative to first-line therapy.

  • Azithromycin is often effective in the eradication of susceptible strains of Streptococcus pyogenes from the nasopharynx.
  • Clindamycin can be used to treat β-hemolytic streptococcal infections, with a treatment duration of at least 10 days. It is essential to perform susceptibility tests before treatment to determine the causative organism and its susceptibility to the chosen antibiotic.

From the Research

Treatment Options for Strep in Adult Males with Penicillin Allergy

  • For adult males with a penicillin allergy, alternative antibiotics can be used to treat strep, including erythromycin and first-generation cephalosporins 4.
  • Macrolides such as clarithromycin and azithromycin are also rational alternatives to erythromycin for streptococcal pharyngitis/tonsillitis in penicillin-allergic patients 5.
  • First-generation cephalosporins are recommended for patients with nonanaphylactic allergies to penicillin 6.
  • However, it's essential to note that there is significant resistance to azithromycin and clarithromycin in some parts of the United States 6.

Evaluation of Penicillin Allergy

  • Many patients report allergies to penicillin, but few have clinically significant reactions 7.
  • Evaluation of penicillin allergy before deciding not to use penicillin or other β-lactam antibiotics is an important tool for antimicrobial stewardship 7.
  • Penicillin testing, including skin testing, patch testing, and graded challenge, can be used to determine the severity of the allergy 8.
  • Desensitization may be used in some cases where treatment with penicillins is essential 8.

Considerations for Antibiotic Treatment

  • The modified Centor score can be used to help physicians decide which patients need no testing, throat culture/rapid antigen detection testing, or empiric antibiotic therapy 4.
  • Guidelines recommend using clinical decision rules to assess the risk of group A beta-hemolytic streptococcal infection, followed by rapid antigen testing if a diagnosis is unclear, before prescribing antibiotics 6.
  • Patients with worsening symptoms after appropriate antibiotic initiation or with symptoms lasting 5 days after the start of treatment should be reevaluated 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diagnosis and treatment of streptococcal pharyngitis.

American family physician, 2009

Research

Macrolides in the management of streptococcal pharyngitis/tonsillitis.

The Pediatric infectious disease journal, 1997

Research

Streptococcal Pharyngitis: Rapid Evidence Review.

American family physician, 2024

Research

Penicillin Allergy: Mechanisms, Diagnosis, and Management.

The Medical clinics of North America, 2024

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.