Guest posting:  Jason Trubiano, Antimicrobial Stewardship, Drug and Antibiotic Allergy Service and Centre for Antibiotic Allergy and
Research, Austin Health, Victoria, Australia. 

• Penicillin allergies are not always lifelong. Approximately 50% are lost over five years.
• A reaction to penicillin during a childhood infection is unlikely to be a true allergy.
• Only 1–2% of patients with a confirmed penicillin allergy have an allergy to cephalosporins.
  In patients with a low risk of severe allergic reactions, cephalosporins are a relatively safe
  treatment option.
• Patients with a history of delayed non-severe reactions, such as mild childhood rashes that
  occurred over 10 years ago, may be suitable for an oral rechallenge with low-dose penicillin. This
  should be done in a supervised hospital environment.
• In many cases, with appropriate assessment and allergy testing, it may be possible to remove the
  penicillin allergy label

Reference

• Devchand M and Trubiano J.  Australian Prescriber, December 2019: 42 : 192-99.