In vivo diagnostic tests in adverse reactions to quinolones.

BACKGROUND AND OBJECTIVE Contradictory reports of the sensitivity of skin tests in quinolone allergy have been reported. Our objectives were to describe the outcome of quinolone skin and challenge tests in patients consulting because of a history of adverse reaction to quinolone and to compare the outcome of quinolone skin tests and challenge tests in the subsample of patients who had undergone both tests. METHODS We reviewed skin and challenge test results of all patients who consulted at our allergy service over the last 5 years because of a history of quinolone adverse reaction in the form of urticaria or anaphylaxis within 1 hour of drug intake (group 1), urticaria or maculopapular eruption between 1 and 24 hours after intake (group 2) or after 24 hours had passed (group 3), or atypical symptoms (group 4). RESULTS A total of 71 cases were identified: 27, 8, 24 and 12 in groups 1 through 4, respectively. Skin tests were performed in all patients, with positive results in 31 patients. In group 1, 62.9 % of these patients showed positive skin tests and 22.2% showed positive challenge tests, whereas in the other 3 groups, about 30% of patients had positive skin tests and a variable percentage (from 0% to 4.1% depending on the group) had positive challenge tests. Quinolone challenge tests were performed in 10 patients with positive skin tests (5 of them with positive results) and in 34 patients with negative skin tests (2 of them with positive results). CONCLUSIONS A highly suggestive history of quinolone allergy is more frequently associated with positive skin tests and positive challenge tests. Therefore, skin tests help to predict the result of the challenge test.