Allergologic tests for drug hypersensitivity: The use of serial dilutions and a patient case

Skin testing for drug hypersensitivity reactions is a valuable diagnostic tool. Various forms of skin testing may be performed, depending on the allergic condition. One variant, intracutaneous testing with injections of suspected allergens, is commonly applied in allergologic practice to evaluate skin reactivity to various allergens. Hospital pharmacists may be frequently confronted with prescriptions for extemporaneous serial dilutions for sterile intradermal injections. Since compounding of such dilutions may be complicated and time-consuming, pharmacists are likely to question the rationale behind such prescriptions. In this paper we provide an overview of the diagnostic options available for drug hypersensitivity reactions and we illustrate the importance of intracutaneous tests by discussing a recent clinical case from our hospital.