D3.59 - Insights from Drug Provocation Testing in Quinolone Allergy

Quinolones are widely prescribed antibiotics known for their broad-spectrum antimicrobial activity and ease of administration. However, allergic reactions to quinolones have become increasingly common, driven by a rise in prescriptions and the introduction of more immunogenic agents such as moxifloxacin. Quinolones are now the third most frequent cause of drug allergies and the second most common in hospitalized patients, accounting for approximately 4.5% of drug-induced anaphylaxis cases. 

In this study, we collected all quinolone provocation tests performed at our hospital in 2024 and assessed their concordance with skin tests (ST) results. Additionally, we explored the prevalence of cross-reactivity between quinolones of different generations, aiming to improve the understanding of diagnostic challenges in managing quinolone hypersensitivity.

We retrospectively collected a sample of 43 patients who underwent a drug provocation test (DPT) with a quinolone at our hospital in 2024. The aim was to demonstrate the validity of skin testing (ST), their correlation with the results of DPT, and the prevalence of cross-reactivity between quinolones from different generations.

Out of the 43 patients, 29 were women and 14 were men. Of these, 24 had experienced an initial reaction with ciprofloxacin, 16 with levofloxacin, and 3 with moxifloxacin. Skin tests were performed on 29 patients, and only 3 of them were positive. In contrast, 5 patients with negative ST had positive DPT. 9 patients with positive DPT were subsequently challenged with another quinolone from a different generation. 4 of these patients also exhibited positive reactions to the second quinolone.12 patients underwent DPT with levofloxacin and 5 of them had a positive reaction. Furthermore, 3 of them experienced severe reactions.

Based on our experience, skin tests are of limited help for diagnosing quinolone hypersensitivity. Although cross-reactivity between quinolones of different generations has been shown to be low, a significant percentage of our patients exhibited positive DPT results to more than one quinolone from different generations. Although the literature identifies levofloxacin as the safest alternative in cases of reactions to other quinolones, among all the patients who underwent a drug provocation test at our hospital, levofloxacin was the quinolone that caused the most positive results.