Criteria for intradermal skin testing and oral challenge in patients labeled as fluoroquinolone allergic

Abstract

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Standards for practical intravenous rapid drug desensitization & delabeling: A WAO committee statement

“…In patients with anaphylactic reactions, it could be argued that the time from the index reaction to the study could be relevant, as patients with positive ST results seem to have a more recent history of a reaction, and thus suggest that sensitization wanes over time. 204 This is in line with findings from other groups. 205,206 However, whether this means clinical allergy wanes over time is unclear, and studies have struggled to find statistical significance when comparing outcomes in patients with more recent vs more distant DHRs.…”

“…203 This has been supported by tolerance of lower dose fluoroquinolones in the vast majority of patients with allergy labels to fluoroquinolones. 204 The apparent lack of crossreactivity between fluoroquinolones may also be supported by the different affinity of fluoroquinolones for this receptor. 203 In addition, true anaphylaxis has been reported to be more common with moxifloxacin which has been estimated to cause approximately 54% of fluoroquinolone associated anaphylaxis.…”

“…However, recent studies suggest that oral DPT may be a valid mechanism to delabel fluoroquinolone IgE mediated reactions and that ST may potentially be used to differentiate IgE and non-IgE mediated mast cell activation. 204,206 These studies suggest that up to 75% or more of those with immediate reactions to fluoroquinolones will tolerate the implicated fluoroquinolone when undergoing diagnostic drug challenge. It is quite likely in these cases that the original reaction may have been more likely related to Mas-related G protein-coupled receptor-X2 (MRGPRX2) activation.…”

“…205,206 SPT and IDT with the highest nonirritating concentrations can be helpful in the diagnosis of a true IgE mediated reaction and to help characterize cross-reactivity. 204…”

Immediate Hypersensitivity to Fluoroquinolones: 
A Cohort Assessing Cross-Reactivity

“…An important distinction between the 2 reaction mechanisms is that, while IgE-antibody reactions tend to occur even with miniscule exposure to the antigen, MRGPRX2-mediated reactions are dose-dependent, and many medications have established half maximal effective concentration (EC 50 ) values [ 23–28 ]. A recent study by Krantz et al proposed new intradermal test criteria followed by single-dose oral challenge—200 mg, 250 mg, and 250 mg for moxifloxacin, levofloxacin, and ciprofloxacin, respectively—that they used for de-labeling of fluoroquinolone drug allergy [ 29 ]. The authors acknowledge, however, that the low-dose oral challenge standard to allergy testing may not account for the dose-dependent nature of non-IgE-mediated reactions.…”