What are the indications for skin testing for penicillin allergy?
Skin testing for penicillin allergy is indicated in patients with a possible or definite past history consistent with immediate hypersensitivity to penicillin and in whom penicillin therapy is indicated and effective alternative antibiotic therapy is not available. Penicillin sensitization occurs by the haptenation mechanism and may involve a number of structural components (or “determinants”) of the penicillin molecule. The penicilloyl determinant is referred to as the major determinant, and the penicillin G, penicilloate, and penilloate determinants are referred to as the minor determinants. This major and minor nomenclature refers only to abundance of breakdown product and does not indicate relative clinical importance, as the minor determinants are responsible for the majority of life-threatening anaphylactic reactions.