From the Guidelines
For patients with a penicillin allergy who have Group A Streptococcus (Strep A) infection, the most appropriate treatment is Cephalexin, 20 mg/kg/dose twice daily (max = 500 mg/dose) for 10 days, as recommended by the Infectious Diseases Society of America 1.
Treatment Options
When considering treatment for Strep A infection in patients with a penicillin allergy, several alternatives are available:
- Cephalexin, an oral cephalosporin, is a strong, high-recommended option 1.
- Cefadroxil, another oral cephalosporin, is also a strong, high-recommended option 1.
- Clindamycin, an oral antibiotic, is a strong, moderate-recommended option 1.
- Azithromycin and Clarithromycin, oral macrolides, are strong, moderate-recommended options, but resistance to these agents is well-known and varies geographically and temporally 1.
Important Considerations
It is essential to note that cephalosporins should be avoided in individuals with immediate-type hypersensitivity to penicillin 1. Completing the full course of antibiotics is crucial to prevent complications like rheumatic fever or kidney inflammation, even if symptoms improve quickly. If symptoms worsen or don't improve within 48-72 hours, medical attention should be sought. Verifying penicillin allergies when possible is also important, as many patients labeled as allergic can actually tolerate penicillins, and having an accurate allergy history improves future 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 Azithromycin is often effective in the eradication of susceptible strains of Streptococcus pyogenes from the nasopharynx 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. In three double-blind controlled studies, conducted in the United States, azithromycin (12 mg/kg once a day for 5 days) was compared to penicillin V (250 mg three times a day for 10 days) in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S. pyogenes)
Treatment for Group A Streptococcus (Strep A) infection in a patient with a penicillin allergy:
- Azithromycin can be used as an alternative to first-line therapy in individuals who cannot use first-line therapy, such as those with a penicillin allergy.
- The recommended dosage of azithromycin for the treatment of pharyngitis/tonsillitis caused by Streptococcus pyogenes is 12 mg/kg once a day for 5 days 2.
- It is essential to perform susceptibility tests to ensure the effectiveness of azithromycin against the specific strain of Streptococcus pyogenes 2.
- Azithromycin has been shown to be effective in eradicating susceptible strains of Streptococcus pyogenes from the nasopharynx 2.
From the Research
Treatment Options for Group A Streptococcus Infection in Patients with Penicillin Allergy
- For patients allergic to penicillin, alternative antibiotics such as macrolides (e.g., erythromycin, clarithromycin, azithromycin) can be used to treat Group A Streptococcus (Strep A) infection 3.
- However, it is essential to note that there is significant resistance to azithromycin and clarithromycin in some parts of the United States, which may limit their use 4.
- First-generation cephalosporins can be recommended for patients with nonanaphylactic allergies to penicillin 4.
- Azithromycin has been shown to be safe in patients allergic to penicillin and/or cephalosporin, with no reactions observed in a study of 48 patients 5.
- A penicillin allergy screening algorithm and penicillin skin testing can be used to transition hospitalized patients from second-line to first-line antibiotic therapy, including β-lactam antibiotics 6.
Considerations for Antibiotic Selection
- The choice of antibiotic should be based on the patient's allergy history, the severity of the infection, and the potential for resistance 3, 4.
- A 10-day treatment course is typically recommended for Strep A infection, but azithromycin may be effective with a shorter treatment duration of 5 days 3.
- It is crucial to follow clinical guidelines and consider the latest evidence when selecting an antibiotic for patients with penicillin allergy 4, 7.