Implications of a Negative Oral Challenge Test

If the oral drug provocation challenge is negative, one should clearly indicate on the prescription that a challenge was done and there was no reaction, to avoid ongoing mislabeling in community pharmacies

The allergies section in the patient chart should also be updated (i.e. Penicillin allergy removed or updated to indicate that oral challenge was tolerated). This does not need to be repeated unless a subsequent episode takes place

If negative, it strongly suggests that your patient will not react to penicillin, amoxicillin or any cephalosporins and that these can safely be given

In 2016, Mill et al published a cohort study of over 800 children that had a label of a suspected penicillin allergy. Each patient was assessed directly with a graded oral provocation challenge:

• 94% of the patients tolerated the provocation challenge with no reaction

• 2.1% developed an immediate reaction, while 3.8% developed a delayed reaction. In these, skin prick testing for penicillin was completed within 2-3 months and only 1 patient tested positive on skin prick testing

Therefore, in children, skin prick and intradermal testing seems unnecessary for penicillin allergy investigations, and a graded oral provocation challenge can be recommended for these patients