D3.56 - Relevant Aspects in the Investigation of Hypersensitivity Reactions to Non-Beta-Lactam Antibiotics
Case report
Introduction:The investigation of hypersensitivity reactions to non-beta-lactam antibiotics is a challenge in clinical practice, as there is no consensus on the standardization of non-irritating concentrations in skin tests.
Case Description:A 25-year-old female patient presented with urticaria and angioedema following the use of clarithromycin and ciprofloxacin. The investigation included a prick test, which returned negative for both substances (clarithromycin 50 mg/ml and ciprofloxacin 0.2 mg/ml). However, the intradermal test was positive for clarithromycin (0.5 mg/ml) and ciprofloxacin (0.02 mg/ml). The patient subsequently underwent an open-label, simple, blinded, placebo-controlled oral provocation test with 500 mg of ciprofloxacin and 500 mg of clarithromycin, both of which were negative.
Discussion:Hypersensitivity reactions to non-beta-lactam antibiotics present challenges in clinical practice, particularly due to the lack of consensus in the literature regarding non-irritating concentrations and the predictive values of skin tests. The patient was stratified as low risk, which justified the oral provocation test; the results were negative for both drugs.
Conclusion:The open-label, simple, blinded, placebo-controlled oral provocation test is an essential tool for diagnosing hypersensitivity reactions to non-beta-lactam antibiotics. The low-risk stratification for this patient was crucial for performing the oral provocation test (the gold standard). Future studies should focus on the standardization of non-irritating concentrations in skin tests and the evaluation of their predictive value in diagnosing hypersensitivity to non-beta-lactam antibiotics.
