Hypersensitivity reactions to cephalosporins: prevalence, classification, and diagnostic challenges

Cephalosporins are among the most frequently used antibiotics, and hypersensitivity reactions to them can significantly com­pli­cate the therapeutic management, especially in acute clinical settings. Accurate identification of allergic patients is essential to avoid mislabeling and unjustified restriction of β-lactam antibiotic treatment.Skin testing (prick and intradermal), used for immediate reac­tions, has variable sensitivity depending on the con­cen­tra­tion employed and the chemical structure of the cephalo­sporin. In vitro tests are limited in availability and utility. For delayed reactions, patch testing or intradermal testing with late reading may be used; however, data on their accuracy are insufficient. Drug provocation testing remains the gold stan­dard for confirming the diagnosis, being particularly recom­men­ded when allergy tests are negative and depending on the severity of the index reaction. Further studies are needed to validate sensitivity and specificity in different pa­tient sub­groups and to optimize testing strategies (Khan et al., 2019; Touati et al., 2020).This paper aims to synthesize, based on the existing literature, the main data regarding the prevalence of hypersensitivity reactions to cephalosporins, associated risk factors, structural classification, current diagnostic methods (both in vivo and in vitro), as well as key aspects related to cross-reactivity with other β-lactams.