The consequences of "labelling"

A label of allergy to penicillin is concerning, and, in adults (who may have been labelled as children), has been shown to delay treatment in emergency settings, result in increased frequency of admissions to hospital, prolonged stay in hospital, and worse outcomes while in hospital

The antibiotics that often replace penicillin are typically more expensive with worse side effects and can contribute to resistance and C. difficile. Penicillin allergies are not genetic, and a family history of penicillin allergy is not sufficient evidence to label a patient as such

The objective of a challenge is to safely de-label patients as having an allergy if appropriate in order that physicians feel safe prescribing penicillin or amoxicillin for patients

Actual IgE-mediated penicillin reactions are rare:

• Approximately 1/10th of the population will self-report a penicillin allergy

• When investigated, only 1/100th of the population will be confirmed to have an IgE-mediated reaction. IgE-mediated penicillin reactions rarely lead to anaphylaxis.

Further, even if a patient has a history of an IgE-mediated reaction, 80% of these patient’s IgE antibodies to penicillin will fade over 10 years

IgE-mediated symptoms typically cause:

• Acute urticaria

• Nausea

• Vomiting

• Respiratory distress

• Cardiovascular compromise