Penicillin Allergy

Guideline for peri-operative care

Cephalosporins may be prescribed to patients with reported penicillin allergy if physicians use this clinical decision support algorithm.

If the reaction to penicillin occurred more than 10 years ago, the likelihood of a reaction to cephalosporin is low due to diminished IgE levels (1).

Only 10% of all patients who report a penicillin allergy are diagnosed as skin-test positive (2). Of those who are skin test positive, there is only 2% cross-reactivity rate with cephalosporins for patients who have a true penicillin allergy (3) (i.e. 0.2% of all patients reporting allergy).

Overall there is less than a 1 in 100,000 risk of anaphylaxis with a cephalosporin in patients reporting a penicillin allergy.

(1) Sullivan, et al. Skin testing to detect penicilin allergy; Journal of Allergy and Clinical Immunology, Vol 68, 1981

(2) Solensky, et al. Drug allergy: an updated practice primer: Annals of Allergy, Asthma & Immunology, Vol 105, Oct 2010

(3) Apter, et al. Is there cross-reactivity between penicillins and cephalosporins?; The American Journal of Medicine, Vol 119, April 2006