1- Immunoallergology Department, Hospital de Dona Estefânia, Centro Hospitalar de Lisboa Central, EPE, Rua Jacinta Marto, Lisbon, Portugal
2- CEDOC, Integrated Pathophysiological Mechanisms Research Group, Nova Medical School, Campo dos Mártires da Pátria, 1150-190 Lisbon, Portugal
- XXXVI European Academy of Allergology Clinical Immunology, Helsínquia, 17-21 Junho 2017
- Apresentação sob a forma de comunicação oral; publicação de resumo
- Reunião internacional
Introduction: Beta-lactams are the most frequent cause of drug reactions mediated by specific immunological mechanisms. Drug provocation tests (DPT) are considered the gold standard in the diagnosis of drug allergy, though in nonimmediate drug reactions reactions (NIR) it is not consensual its optimal duration.
Objectives: To compare two distinct protocols of DPT in patients with history of NIR to beta-lactams.
Methods: A retrospective study of patients with history of beta-lactam NIR (>1 hour after last administration) was conducted in our Department, between January 2014 and June 2016. Data was collected from patients' electronic medical records. The protocols consisted in: Protocol 1 – administration of beta-lactam in gradually increasing doses, in hospital setting, until treatment dose was reached. Protocol 2 - administration of beta-lactam in gradually increasing doses, in hospital setting, until treatment dose was reached, followed by continuation of medication at home (minimum 3 days).
Results: During the referred period 111 DPT, with the characteristics described above, were performed. The majority of patients were female (53%). Median age at time of reaction was 4 years (p25-p75: 2-14.5 years). In terms of severity, 44% had history of mild reaction, 54% moderate and 3% of severe reaction. Mean day of occurrence of self-reported reaction was 3 days (p25-p75: day 3 – day 5). The antibiotics associated with the reactions, and used in the DPT, were in 51% of cases amoxicillin-clavulanic acid, 46% amoxicillin and in 3%, cephalosporins. 57 patients followed protocol 1 and 54 protocol 2. From those 57 patients on protocol 1, four (7.5%) had a positive DPT and from those 54 following protocol 2, five DPT were positive (10.2%). There were no statistically significant differences between protocols in regards to DPT outcome (p=0.931), severity of the reaction (p=0.934) or age at the time of self-reported reaction (p=0.734).
Conclusions: In our sample the frequency of positive DPT was low. There were no statistically significant differences in relation to positivity of DPT between protocols. These results suggest that both protocols may be valid options in the work-up of NIR, however more studies with a larger population are needed.
Palavras Chave: Drug allergy, Beta-lactam allergy, Drug provocation challenge