What is the treatment for streptococcal pharyngitis in a patient with a penicillin allergy?

From the Guidelines

For patients with strep pharyngitis who have a penicillin allergy, azithromycin for 5 days is the recommended treatment option. According to the 2012 update by the Infectious Diseases Society of America 1, treatment of GAS pharyngitis in penicillin-allergic individuals should include azithromycin for 5 days, among other options. The recommended dosage is not specified in the guideline, but a common regimen is azithromycin 500 mg on day 1, followed by 250 mg daily for 4 more days.

Alternative Options

Other effective options include:

• Clindamycin for 10 days
• Clarithromycin for 10 days
• A first-generation cephalosporin for 10 days, for those not anaphylactically sensitive to penicillin, as cross-reactivity is low (around 1-10%) 1. It's essential to complete the full course of antibiotics even if symptoms improve quickly to prevent complications like rheumatic fever or kidney inflammation. Patients should also use symptomatic treatments such as acetaminophen or ibuprofen for pain and fever, salt water gargles for throat discomfort, and maintain adequate hydration. Treatment should begin promptly to reduce symptom duration and prevent complications. If symptoms don't improve within 48-72 hours of starting antibiotics, patients should follow up with their healthcare provider.

From the FDA Drug Label

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) Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30 with the following clinical success (i.e., cure and improvement) and bacteriologic efficacy rates (for the combined evaluable patient with documented GABHS): Three U. S. Streptococcal Pharyngitis Studies Azithromycin vs. Penicillin V EFFICACY RESULTS Day 14Day 30 Bacteriologic Eradication: Azithromycin323/340 (95%)255/330 (77%) Penicillin V242/332 (73%)206/325 (63%) Clinical Success (Cure plus improvement): Azithromycin336/343 (98%)310/330 (94%) Penicillin V284/338 (84%)241/325 (74%)

Azithromycin is a suitable alternative for the treatment of strep pharyngitis in patients with a penicillin allergy, with a clinical success rate of 98% at Day 14 and 94% at Day 30, and a bacteriologic eradication rate of 95% at Day 14 and 77% at Day 30 2.

• Key benefits of azithromycin include its effectiveness against Group A β-hemolytic streptococci and its relatively low incidence of treatment-related adverse events, primarily gastrointestinal.
• Common side effects include diarrhea/loose stools, vomiting, and abdominal pain.

From the Research

Strep Pharyngitis and Penicillin Allergy

• Patients with a penicillin allergy require alternative treatments for streptococcal pharyngitis, as penicillin is the primary drug of choice 3, 4, 5.
• Macrolides, such as erythromycin, clarithromycin, and azithromycin, are potential alternatives for patients with penicillin allergies 3, 6.
• First-generation cephalosporins are also recommended for patients with non-anaphylactic penicillin allergies 4, 5.
• Azithromycin has been shown to have similar clinical efficacy to penicillin, but with lower bacteriologic eradication rates 6.
• A systematic review found that cephalosporins, macrolides, and carbacephem may have similar or slightly better symptom resolution rates compared to penicillin, but the evidence is uncertain due to low-certainty studies 7.

Treatment Options

• Erythromycin is generally effective, but its use is complicated by multiple daily doses, a lengthy treatment period, and gastrointestinal side effects 3.
• Clarithromycin and azithromycin offer more convenient dosing and lower rates of gastrointestinal complaints 3.
• Azithromycin has a recommended treatment duration of 5 days, compared to 10 days for penicillin, erythromycin, and clarithromycin 3, 6.
• First-generation cephalosporins are recommended for patients with non-anaphylactic penicillin allergies, with a treatment duration of 10 days 4, 5.

Considerations

• The choice of antibiotic should be based on the patient's allergy status, the severity of symptoms, and the risk of complications 4, 5, 7.
• Patients with worsening symptoms or persistent infection after treatment should be reevaluated 5.
• Tonsillectomy is rarely recommended as a preventive measure, and only in cases with recurrent streptococcal pharyngitis 5.