1 - Serviço de Imunoalergologia, Hospital Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central
2 - Centro Clínico Académico de Lisboa
3 - CHRC, NOVA Medical School, Universidade NOVA de Lisboa
- Comunicação oral em congresso internacional: European Academy of Allergy and Clinical Immunology (EAACI) Annual Congress 2023
Background: Beta-lactams are the drugs more frequently responsible for hypersensitivity reactions. We aimed to characterize patients from our Allergy Department for suspected beta-lactam allergy.
Method: Retrospective study, including all patients followed for beta-lactam allergy from 2010 to 2019, submitted to skin testing. Data from electronic records were collected and analysed.
Results: Our population consisted of 582 patients (394 adults and 188 children), 406 (69.8%) females, aged (mean+SD) 35.7+23.1 years. Amoxicillin with clavulanate was the most frequently implied drug, accounting for 42.4% (n=247) of reactions. Immediate, nonimmediate, and unknown timing reactions to beta-lactams were reported by 207 (35.6%), 303 (52.1%), and 72 (12.4%) patients records. Regarding immediate reactions, 47 (22.7%) patients had positive skin tests (ST), and 32 performed a drug provocation test (DPT) with an alternative beta-lactam, which was negative in 30, positive in 1, and inconclusive in 1 case. ST were negative in 158 patients, and 120 performed a DPT, which was positive in 8 patients, 6 with the offending drug and 2 with an alternative. Concerning nonimmediate reactions, 29 patients (9.6%) had positive skin tests. Of those, 18 went through a DPT with an alternative drug, which was negative in all. Negative ST were found in 273 (90.1%) of patients reporting nonimmediate reactions, and 215 were challenged, with only 15 (7.0%) positive DPTs. In patients with unknown reaction timing, 6 (8.3%) had positive ST. Of the remaining 66 (ST negative), 49 performed a DPT, which were positive in 3 (6.1%). Overall, ST were positive in 82 (14,1%) patients, more commonly in immediate reactions (p<0.05). Only 3 (0.5%) patients suffered systemic reactions while performing ST, which were mild, and responded to oral medication. DPTs were positive in 26 of 384 (6.8%) patients with negative ST. Confirmed beta-lactam allergy was more common in adults (n=85; 21.6%) vs. children (n=23; 12.2%).
Conclusion: Beta-lactam allergy was confirmed in 108 (18.6%) of the suspected patients, mostly in adults. Skin tests seem to be a safe diagnostic method. DPT increased the diagnostic accuracy of beta-lactam allergy.
Palavras Chave:Allergy diagnosis, Drug allergy, Immunologic tests, beta-lactam allergy