Diagnosis of Quinolone Hypersensitivity: An EAACI Position Paper

Hypersensitivity reactions to quinolones (QHRs) have been increasing in frequency, thus classifying them as the second most frequently implicated class of antibiotics in hypersensitivity reactions (HRs). It is noteworthy that quinolones (Qs) have been observed to predominantly trigger immediate hypersensitivity reactions (IHRs). These reactions are categorized as either IgE-mediated or non-IgE-mediated, attributable to the off-target occupation of the recently described receptor, Mas-related G-protein coupled receptor member X2 (MRGPRX2), on effector cells. The increasing trend of HRs underscores the necessity for enhanced diagnostic and management strategies. The present position paper aims to shed light on the key mechanisms involved in immediate and non-immediate QHRs. The clinical spectrum of these reactions is discussed, as well as the utility of skin tests, in vitro diagnostic tests, and drug provocation tests in diagnosis. A further focal point of this study is the analysis of cross-reactivity between various Qs. The paper concludes with the presentation of diagnostic algorithms for both immediate and non-immediate QHRs. The paper's findings aid clinical practice for QHRs and address unmet needs, which should stimulate more in-depth investigations into the mechanisms and clinical practice of QHRs.