Which antibiotic is the best choice for a patient with a severe allergy to penicillin and strep throat?

Azithromycin is the best choice for a patient with a severe allergy to penicillin who has strep throat due to its effectiveness against Streptococcus pyogenes, the bacteria commonly responsible for this infection. Azithromycin is a macrolide antibiotic that can be used as an alternative in patients who cannot tolerate penicillin. It works by inhibiting bacterial protein synthesis, thereby hindering the growth and replication of the bacteria.

In the context of a severe allergy to penicillin, using cephalexin and cefuroxime axetil is generally contraindicated because these cephalosporin antibiotics share a similar beta-lactam structure with penicillin and may also pose a risk of cross-reactivity in patients with severe penicillin allergies.

Levofloxacin, while effective against various bacterial infections, is not typically the first-line treatment for strep throat due to concerns about broader-spectrum antibiotics contributing to antibiotic resistance, and its use may be reserved for more complicated cases or when other antibiotics are not suitable.

Overall, azithromycin is preferred in this scenario because it provides a targeted approach to treating strep throat while minimizing the risk associated with the patient's penicillin allergy.