Allergic reactions to penicillins and cephalosporins: diagnosis, assessment of cross-reactivity and management.

Introduction: Beta-lactams (BL) are the main cause of allergic drug reactions mediated by specific immunological mechanisms. Reactions can be IgE or effector T-cell mediated. The new antigenic determinants are recognized by the immunological system in the context of the common beta-lactam structure or the specific differences in the side chains of the antibiotics of this family plus the protein carrier. Areas covered: We have reviewed the recent clinical literature concerning new clinical entities, the progress in diagnosis including the difficulties for in in vivo and or in vitro testing as well as the new algorithms proposed for delabelling subjects classified as allergic to beta-lactams, and recommendations for desensitization procedures. Expert opinion: The knowledge gained over the last years on beta-lactam hypersensitivity has enabled a better understanding and management of cases with allergic reactions to beta-lactams.