KEY POINTS
- Benzylpenicilloyl polylysine (PRE-PEN) is the major determinant used to perform a penicillin skin test
- Can be used with the minor determinant (penicilloate or penilloate) to increase the reliability of penicillin skin testing
- Penicillin skin testing can identify the presence of an IgE-mediated penicillin allergy
- Patients with history of severe non-IgE mediated reactions such as Steven Johnson Syndrome or Toxic Epidermal Necrolysis should not be tested
- The predictive value of penicillin skin testing when using both the major and minor determinants is reported between 97% and 99%
- Typically done as a puncture (i.e., scratch) test followed by an intradermal test
- An oral challenge can be given if the scratch and intradermal tests are negative, which increases the predictive value of the penicillin skin testing
- See below link for how to test
- Concurrent antihistamine use may confound testing
- Penicillin skin testing has been performed by a variety of healthcare practitioners, from allergists to nurses to pharmacists
- Use of penicillin skin testing is only effective if the patient is aware of the result, the test is documented in the medical chart and the chart is updated appropriately to show the patient’s correct allergy status. If these tasks are not completed the allergy label may go unchanged after a negative result, therefore serving to be of no benefit of the patient.
RESOURCES