PulmCrit – Is piperacillin-tazobactam safe in patients with penicillin allergy?

Historically it was believed that allergic reactions could be mediated by the core structures. This would imply that a patient could be allergic to all penicillins, all cephalosporins, or even all beta-lactams. That would be hugely problematic, because a patient could simultaneously be allergic to dozens of antibiotics – greatly complicating their management.