An 18-year-old with Streptococcus pyogenes pharyngitis and an anaphylactic reaction to penicillin; most appropriate treatment?

An 18-year-old with Streptococcus pyogenes pharyngitis and an anaphylactic reaction to penicillin; most appropriate treatment?

• A. Doxycycline 100 mg bid x 10 days
• B. Gargle with salt water
• C. Keflex 250 mg qid x 10 days
• D. Clarithromycin 250 mg bid x 10 days

Answer: (D)

When treating strep throat in someone with a history of anaphylaxis to penicillin, avoid beta-lactams entirely and choose a non–beta-lactam antibiotic with solid Streptococcus pyogenes coverage. Clarithromycin, a macrolide, fits this need well: it reliably covers GAS and is approved for penicillin-allergic patients. The dosing of 250 mg twice daily for about 10 days provides an effective course to eradicate the infection while avoiding the offending penicillin. Other options don’t fit as well. Doxycycline can be used in penicillin allergy but is not preferred for streptococcal pharyngitis due to rising resistance and less ideal activity against GAS. Gargling with salt water is supportive care and insufficient as sole therapy. Keflex (cephalexin) is a beta-lactam and should be avoided in a true penicillin allergy with anaphylaxis.

When treating strep throat in someone with a history of anaphylaxis to penicillin, avoid beta-lactams entirely and choose a non–beta-lactam antibiotic with solid Streptococcus pyogenes coverage. Clarithromycin, a macrolide, fits this need well: it reliably covers GAS and is approved for penicillin-allergic patients. The dosing of 250 mg twice daily for about 10 days provides an effective course to eradicate the infection while avoiding the offending penicillin.

Other options don’t fit as well. Doxycycline can be used in penicillin allergy but is not preferred for streptococcal pharyngitis due to rising resistance and less ideal activity against GAS. Gargling with salt water is supportive care and insufficient as sole therapy. Keflex (cephalexin) is a beta-lactam and should be avoided in a true penicillin allergy with anaphylaxis.