Approach to the patient with drug allergy

Clinicians commonly encounter patients who report to have drug allergy. In a large part, such allergy corresponds to adverse drug reactions, which are not immune mediated. The incriminated drug need not always be avoided for further therapy. On the other hand, drug allergy may manifest in many unexpected clinical pictures and thus not be recognized. There is no single standardized diagnostic test to confirm the immune-mediated mechanism and to identify the causative drug. Therefore, immune-mediated drug hypersensitivity reactions and their causative drugs have to be considered by the constellation of exposure, timing, and clinical features, including the pattern of organ manifestation. Prior experience with the drug is also an important feature. An allergologic workup with additional investigation may provide some help. Patients should be informed carefully about their drug allergy, whereby symptoms, drug that elicits reaction, modes of diagnosis of drug allergy, and possibly alternatives should be indicated in their allergy passport.

Approach to the patient with drug allergy

Drug allergies are adverse drug reactions mediated by the specific immune system. Despite characteristic signs (eg, skin rash) that raise awareness for possible drug allergies, they are great imitators of disease and may hide behind unexpected symptoms. No single standardized diagnostic test can confirm the immune-mediated mechanism or identify the causative drug; therefore, immune-mediated drug hypersensitivity reactions and their causative drugs must be recognized by the constellation of exposure, timing, and clinical features including the pattern of organ manifestation. Additional allergologic investigations (skin tests, in vitro tests, provocation tests) may provide help in identifying the possible eliciting drug.