What are the treatment options for streptococcal pharyngitis in patients with a penicillin (Penicillin) allergy?

From the Guidelines

For patients with strep throat who have a penicillin allergy, the recommended treatment is typically a macrolide antibiotic such as azithromycin (12 mg/kg once daily, up to a maximum of 500 mg, for 5 days) or clarithromycin (7.5 mg/kg/dose twice daily, up to a maximum of 250 mg/dose, for 10 days), as these have been shown to be effective in treating GAS pharyngitis with a strong, moderate level of evidence 1. Alternatively, clindamycin (7 mg/kg/dose 3 times daily, up to a maximum of 300 mg/dose, for 10 days) is also effective, although with a strong, moderate level of evidence as well 1. For those with non-severe penicillin allergies, first-generation cephalosporins like cephalexin (20 mg/kg/dose twice daily, up to a maximum of 500 mg/dose, for 10 days) may be used, as cross-reactivity is low (around 5-10%) 1. It's essential to complete the full course of antibiotics even if symptoms improve to prevent complications like rheumatic fever. Symptomatic relief can be achieved with acetaminophen or ibuprofen for pain and fever, along with warm salt water gargles and adequate hydration. These alternative antibiotics work by different mechanisms than penicillin but are equally effective at eliminating the Streptococcus pyogenes bacteria that cause strep throat. If symptoms don't improve within 48-72 hours of starting treatment, follow-up with a healthcare provider is recommended. Key considerations in selecting an antimicrobial for treatment of GAS pharyngitis include efficacy, safety, antimicrobial spectrum, dosing schedule, compliance with therapy, and cost, as outlined in the clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis 1. The prevention of rheumatic fever and diagnosis and treatment of acute streptococcal pharyngitis are also critical, with recommended treatment schedules including intramuscular benzathine penicillin G and oral penicillin V, except in individuals with histories of penicillin allergy 1.

Some key points to consider:

• The importance of accurate diagnosis of streptococcal pharyngitis to prevent inappropriate administration of antimicrobials to large numbers of patients with nonstreptococcal pharyngitis 1.
• The need to exclude the diagnosis of GAS pharyngitis to prevent unnecessary exposure to the expense and hazards of antimicrobial therapy 1.
• The potential for antimicrobial resistance among common pathogens, highlighting the importance of judicious use of antibiotics 1.
• The role of symptomatic relief and supportive care in managing strep throat, in addition to antibiotic treatment 1.

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 for strep throat with 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 drug label recommends azithromycin for the treatment of pharyngitis/tonsillitis caused by Streptococcus pyogenes in individuals who cannot use first-line therapy 2.
• It is essential to perform susceptibility tests before treatment to determine the causative organism and its susceptibility to azithromycin.
• Azithromycin may be initiated before results of these tests are known, and antimicrobial therapy should be adjusted accordingly if necessary.
• Data establishing efficacy of azithromycin in subsequent prevention of rheumatic fever are not available 2.

From the Research

Treatment Options for Strep Throat with Penicillin Allergy

• For patients allergic to penicillin, alternative antibiotics are required to treat strep throat, as penicillin is the primary drug of choice 3.
• Erythromycin is generally effective, but its use is often complicated by gastrointestinal side effects, especially in children 3.
• Newer macrolides, such as clarithromycin and azithromycin, offer lower rates of gastrointestinal complaints and more convenient dosing, making them rational alternatives to erythromycin for penicillin-allergic patients 3.
• First-generation cephalosporins are also options for patients with penicillin allergy, and some advocate for their use in all non-allergic patients due to better eradication of group A beta-hemolytic streptococcus (GABHS) 4.

Specific Antibiotic Recommendations

• Azithromycin is recommended for once-daily administration, with a treatment duration of 5 days, compared to 10 days for penicillin, erythromycin, and clarithromycin 3.
• A 3-day azithromycin regimen has been shown to have similar clinical efficacy to a 10-day penicillin V regimen, but with lower bacteriologic eradication rates 5.
• First-generation cephalosporins are recommended for patients with non-anaphylactic allergies to penicillin, with a 10-day course of treatment 6.

Considerations for Treatment

• The choice of antibiotic should be based on the patient's allergy status, as well as the potential for gastrointestinal side effects and the convenience of dosing 3, 4.
• Resistance to azithromycin and clarithromycin is a concern in some parts of the United States, and should be taken into account when selecting an antibiotic 6.
• Patients with worsening symptoms after antibiotic initiation or with symptoms lasting 5 days after the start of treatment should be reevaluated 6.