Skin testing with penicilloyl-polylysine (PPL) and minor determinant mixture (MDM) does not contribute to evaluation of nonimmediate reactions

Contribution of skin testing with PPL and MDM in diagnosing cell-mediated hypersensitivity reactions to penicillins actually was "null" in a recent study.

"In cases of nonimmediate reactions (i.e., occurring more than one hour after the drug administration), it is mandatory to test the suspected penicillin (e.g., amoxicillin, ampicillin, etc.)."

All but 4 patients (97.5%) had positive responses to the responsible penicillins. Only 5.5% were positive to PPL (all immediate-reading) and only 10.5% were positive to MDM.

Manifestations of beta-lactams hypersensitivity: MAUS (click to enlarge the images).

Mnemonics for penicillin allergy skin testing

Major penicillin determinant test detects

Majority of patients with penicillin allergy

Minor determinant test

Minorizes the risk

References:

Recommended Tests Not Useful for Gauging Nonimmediate Penicillin Reactions. Medscape.

Adverse Reactions to Drugs: A Short Review
Mind Maps: Drug Allergy
Mnemonics: Drug Allergy

Pearls and Pitfalls of Allergen Testing - JCAAI http://goo.gl/6ThcC and http://goo.gl/Bfnhn

Image source: Penicillin nucleus, Wikipedia, GNU Free Documentation License.