What is the treatment for streptococcal (strep) throat in a patient with an allergy to penicillin (PCN) and sulfonamides?

From the Guidelines

If you're allergic to penicillin and sulfa drugs, the most effective treatment option for strep throat is azithromycin, typically prescribed as a 5-day course with a higher dose on the first day (500mg) followed by 250mg daily for 4 more days, as recommended by the Infectious Diseases Society of America 1. This recommendation is based on the strongest and most recent evidence, which prioritizes morbidity, mortality, and quality of life as the outcome. The following points support this recommendation:

• Azithromycin is a macrolide antibiotic that inhibits bacterial protein synthesis, making it effective against Group A Streptococcus while avoiding allergic reactions in penicillin-sensitive patients.
• The dosage and duration of azithromycin treatment are supported by clinical practice guidelines, which recommend a 5-day course for the treatment of strep throat in penicillin-allergic individuals 1.
• Alternative treatment options, such as clindamycin and clarithromycin, are also available, but azithromycin is generally considered the first-line treatment due to its efficacy and safety profile.
• It's essential to complete the full course of antibiotics, even if symptoms improve quickly, to prevent complications like rheumatic fever or kidney inflammation.
• While taking antibiotics, it's recommended to stay hydrated, use throat lozenges or warm salt water gargles for comfort, and take acetaminophen or ibuprofen for pain and fever if not contraindicated by other medical conditions. Some key points to consider when treating strep throat in penicillin-allergic individuals include:
• The importance of selecting an antimicrobial agent that is effective against Group A Streptococcus, such as azithromycin, clindamycin, or clarithromycin.
• The need to consider the patient's allergy history and potential cross-reactivity with other antibiotics, such as cephalosporins.
• The recommendation to avoid broad-spectrum antibiotics, such as fluoroquinolones, due to their potential to promote antimicrobial resistance. Overall, the treatment of strep throat in penicillin-allergic individuals requires careful consideration of the patient's allergy history, the efficacy and safety of available antimicrobial agents, and the potential risks and benefits of different treatment options.

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

Treatment of strep throat if allergic to penicillin: Azithromycin can be used as an alternative to first-line therapy in individuals who cannot use first-line therapy, such as those allergic to penicillin.

• Key points:
  • Azithromycin is effective in the eradication of susceptible strains of Streptococcus pyogenes from the nasopharynx.
  • Susceptibility tests should be performed when patients are treated with azithromycin.
  • Data establishing efficacy of azithromycin in subsequent prevention of rheumatic fever are not available. 2

From the Research

Treatment Options for Strep Throat

If a patient is allergic to penicillin, there are alternative treatment options available for strep throat.

• First-generation cephalosporins are recommended for patients with nonanaphylactic allergies to penicillin 3.
• Azithromycin and clarithromycin can also be used, but there is significant resistance to these antibiotics in some parts of the United States 3, 4, 5.
• Clarithromycin has been shown to be as effective as penicillin in the treatment of streptococcal pharyngitis 5.
• Azithromycin has also been shown to be effective in the treatment of upper respiratory tract infections, including streptococcal pharyngitis 4.

Penicillin Allergy Evaluation

Before deciding not to use penicillin or other β-lactam antibiotics, it is important to evaluate the patient's penicillin allergy history.

• A penicillin allergy history algorithm (PAHA) can be used to identify patients who are likely to be skin-test negative and can be transitioned to first-line β-lactam antibiotic therapy 6.
• Penicillin skin testing (PST) can also be used to evaluate patients with a history of penicillin allergy 7, 6.
• Many patients who report a penicillin allergy do not have a clinically significant reaction, and evaluation of penicillin allergy can help to identify these patients and allow for the use of first-line antibiotics 7.

Considerations for Patients with a History of Penicillin Allergy

Patients with a history of penicillin allergy should be evaluated on a case-by-case basis to determine the best course of treatment.

• Patients with a low-risk history of penicillin allergy may be able to receive penicillin or other β-lactam antibiotics after evaluation with a PAHA and/or PST 7, 6.
• Patients with a moderate- or high-risk history of penicillin allergy shouldn't receive penicillin or other β-lactam antibiotics without further evaluation 7.