ABSTRACT
Beta-lactam (BL) drugs are the antibiotics most prescribed worldwide due to their broad spectrum of action. They are also the most frequently implied in hypersensitivity reactions with a known specific immunological mechanism. Since the commercialization of benzylpenicillin, allergic reactions have been described; over the years, other new BL drugs provided alternative treatments to penicillin, and amoxicillin is now the most prescribed BL in Europe. Diagnosis of BL allergy is mainly based on skin tests and drug provocation tests, defining different sensitization patterns or phenotypes. In this study, we evaluated 619 patients with a confirmed diagnosis of BL-immediate allergy during the last 25 years, using the same diagnostic procedures with minor adaptations to the successive guidelines. The initial eliciting drug was benzylpenicillin, which changed to amoxicillin with or without clavulanic acid and cephalosporins in recent years. In skin tests, we found a decrease in sensitivity to major and minor penicillin determinants and an increase in sensitivity to amoxicillin and others; this might reflect that the changes in prescription could have influenced the sensitization patterns, thus increasing the incidence of specific reactions to side-chain selective reactions.
ABSTRACT
Gadolinium-based contrast agents (GBCAs) are frequently used in magnetic resonance imaging (MRI) examinations to increase sensitivity in diagnoses. Recently, an increase in the description of hypersensitivity reactions to GBCAs has been detected. We performed research in PubMed, PubMed, SCOPUS, and EMBASE until September 2021, searching for studies regarding immediate and delayed hypersensitivity reactions to gadolinium-based contrast agents in which an allergy study was performed. The initial research identified 149 articles written in English. After excluding articles duplicated and articles that had irrelevant designs, 26 articles were included. Finally, 17 studies concerning immediate reactions, six studies concerning non-immediate reactions, and three concerning both that performed allergy evaluations were selected. In the review, we analyzed the characteristics of immediate and delayed reactions and the results of the allergy study and cross-reactivity. Skin tests seem to have acceptable accuracy, but drug provocation tests are still needed when skin tests are negative o to find alternative agents. Although cross-reactivity patterns are not well established, cross-reactivity seems to exist among macrocyclic agents. Notwithstanding, the number of patients analyzed is low and further studies are required. A management algorithm is suggested.
