Objective: In our population the properties of hypersensitivity reactions to antibiotics aren`t well studied. The aim of our study is to determine the rate of hypersensitivity reactions to different antibiotics and the appropriate method to find out alternatives.
Materials and Methods: 393 patients, self reporting hypersensitivity reactions to drugs within the past year were enrolled. History was taken and the reported reactions to antibiotics were classified. Skin tests with alternative antibiotics were applied. Double-blind placebo controlled drug provocation tests were done to the patients with negative skin test results.
Results: 192 (48.9%) patients were determined as having hypersensitivity reactions to antibiotics. These reactions were not associated with atopy, asthma or chronic urticaria. The reported antibiotics were amoxicillin (15.3%), penicillin (12.5%), ampicillin (12%), quinolones (5.9%), 2nd generation cephalosporins (5.3%), clarithromycin (4.8%), sulphonamides (3.6%), clindamycin (2%), 1st generation cephalosporins (2%), 3rd generation cephalosporins (1.5%), gentamycin (1.3%), tetracycline (1.3%), and macrolides (< 1%) respectively. The most frequent reaction was urticaria, followed by anaphylaxis and other skin reactions. Thirty six out of 40 patients, 77 of 82 patients and 35 of 38 patients with negative skin test results due to ciprofloxacin, cefuroxime acetyl and clindamycin were successfully challenged with each drug respectively. Most of the patients reporting hypersensitivity reactions to amoxicillin, ampicillin and penicillin did not react to cefuroxime acetyl (29/31, 22/25, 18/20 patients, respectively) and clindamycin (21/29, 22/24, 15/17 patients, respectively) in challenge tests. None of the patients with negative challenge tests returned to the clinic due to following adverse reactions.
Conclusion: In our study population aminopenicillins and penicillin are likely to be the most frequent causes of hypersensitivity reactions and clindamycin and cefuroxime axetyl seem to be safe alternatives. Although skin test results were mostly concordant with double blind placebo controlled drug provocation tests, double-blind placebo controlled drug provocation tests must be applied in all patients as a confirmative diagnostic procedure in antibiotic allergy.