Introduction: Immediate hypersensitivity reactions to quinolones are rare. Moxifloxacin is a new quinolone chemically different from other fluoroquinolones. We report 6 patients diagnosed with hypersensitivity to different fluoroquinolones in whom the response to moxifloxacin and cross-reactivity with other quinolones was studied.

Material-Methods: An allergenic study was made by prick and intradermal test with different fluoroquinolones, in all the patients. Single blind oral challenge tests were performed with moxifloxacin in all the patients, with ciprofloxacin in five patients, with levofloxacin in three patients and with ofloxacin in one patient.

Results: The skin test performed with moxifloxacin was positive in five patients, and the oral challenge test was positive in all six patients. All the patients had at least one positive skin test with some of the other fluoroquinolones.

Conclusion: The skin test with different quinolones seems to be sensitive at showing group hypersensitivity, but not at predicting specific tolerance of each drug.
We found a high degree of cross-reactivity among fluoroquinolones, so we currently recommend to avoid the group. We did not find that moxifloxacin differed from other fluoroquinolones so we cannot recommend it as a valid therapeutic alternative in patients sensitized to other quinolones.

Key words: hypersensitivity, moxifloxacin, quinolones, skin test.