D1.237 - What Do Drug Skin Tests Tell Us About Quinolone Allergy? Adult Allergy Reference Center Experience

Hypersensitivity reactions (HSR) to quinolones are the most common among non-beta lactam antibiotics and can develop through IgE/non-IgE-mediated mechanisms. The diagnostic importance of drug skin tests (DSTs) with quinolones varies, and the gold standard is to perform an oral provocation test (OPT).We aimed to examine the findings of HSRs developed with quinolones and the importance of DTSs in diagnosis.

A total of 2365 hospital records of the patients who were administered to our adult allergy outpatient clinic for drug allergy and underwent DSTs between January 2020 and April 2024 were retrospectively reviewed. 29 cases who underwent DST due to quinolone HSRs were included in the study; demographic data, the results of the drug DSTs, and OPTs were examined.

Of the patients with quinolone HSRs, 69% were female (n=20) and the mean age was 46.4 (19-81) years. The most common clinical presentation was isolated angioedema (31%). Twenty-three of the cases had concomitant non-quinolone drug allergy and 7 had a history of atopic disease (Table 1). Immediate HSRs were observed in 93% of the cases and were most commonly presented as isolated cutaneous reactions (n=22). The most common culprit according to the the patients’ history was ciprofloxacin (58%), followed by moxifloxacin (n=8) and levofloxacin (n=6) (2 cases had experienced HSRs with 2 different quinolons). As we investigated the anaphylaxis (4/8) and urticaria-angioedema (9/18) presentations, the most common culprit was ciprofloxacin. Anaphylaxis was not described with levofloxacin (Table 2). A total of 19 DSTs were applied to 16 cases (4 with culprits; ciprofloxacin:2, levofloxacin:2, and 15 with alternatives; moxifloxacin:6, ciprofloxacin:4, levofloxacin:5). All DSTs were positive with levofloxacin; 50% were positive with ciprofloxacin and moxifloxacin. DSTs were positive in 12 cases (3 with culprits and 9 with alternatives). OPTs were performed with 1 culprit and 2 alternatives. 1 OPT with alternative resulted in positive. Direct OPTs (10 with alternatives, 1 with culprit; levofloxacin:8, moxifloxacin:2, and ciprofloxacin:1) were performed in 11 cases. Two OPTs performed with levofloxacin (1 with a culprit and 1 with an alternative) resulted in positive (Table 3). When we consider the patients with negative DSTs, all of the OPTs resulted without any HSRs. Seventy-eight percent  (11/14) of our cases received the alternative quinolone without any HSRs.

While the high positivity rates in DSTs performed with alternative quinolones made us think of non-IgE-mediated reactions (such as MGRPX2-mediated), the safe results of OPTs in all DST-negative cases showed us that the negative predictive value of our DSTs is high. Cross-reactions between quinolones were rare, showing us that all of them should not be considered as risky as this group of antibiotics has very high importance in recent therapies.