D2.413 - Diagnostic Value of the Basophil Degranulation Test in High-Risk Drug-Induced Anaphylaxis

Identification of the culprit drug in patients with drug-induced anaphylaxis may be challenging, particularly when drug provocation testing carries a high clinical risk. This study aimed to evaluate the clinical and laboratory characteristics of patients who underwent in-vitro basophil degranulation testing (BDT) due to high-risk drug anaphylaxis.

Ten patients with a history of drug-induced anaphylaxis who were considered high risk for drug provocation testing were included. Demographic data, comorbidities, characteristics of the index reaction, and laboratory parameters (baseline serum tryptase, eosinophil count and percentage, total IgE levels) were recorded. Suspected drugs and BDT positivity were analyzed.

The mean age was 46.4 ± 15.1 years, and 70% were female. Atopy was present in 30%, asthma in 20%, and chronic urticaria in 20% of patients. All patients had a history of anaphylaxis with the index drug, and BDT was positive for the culprit drug in 100% of cases. Clarithromycin and amoxicillin-clavulanate were the most frequently identified agents. Cutaneous and respiratory involvement were observed in 50% of index reactions. The mean baseline tryptase level was 3.0 ± 2.9 ng/mL, and the mean total IgE level was 466 ± 677 IU/mL.

In patients with high-risk drug-induced anaphylaxis, BDT provided diagnostic confirmation without the need for drug provocation testing. The concordance between clinical anaphylaxis and in-vitro immunologic response suggests that BDT may represent a safe and effective diagnostic approach in selected high-risk patients when performed in experienced centers.