Methods: We evaluated 20 patients with confirmed immediate allergic reactions to PPI. Patients with anaphylaxis or shock were diagnosed by clinical history, once other possible causes were ruled out, and those with urticaria by DPT. BAT with omeprazole, lansoprazole, and pantoprazole were performed in all patients and in 14 subjects with good tolerance to PPI.
Results: The PPIs involved were omeprazole (N=18) and lansoprazole (N=2). A total of 11 cases (55%) reported anaphylaxis, 7 (35%) anaphylactic shock and 2 (10%) urticaria. BAT was positive in 16 cases (66.66%): 13 (81.25%) to omeprazole, 6 (37.5%) to pantoprazole and 2 (12.5%) to lansoprazole. No differences were found in the time between the reaction and the study comparing those patients who gave a positive BAT results and those who were negative. BAT specificity was 78.57%.
Conclusions: Immediate hypersensitivity reactions to PPI do occur, with omeprazole being the drug most frequently involved and anaphylaxis the most common clinical entity. BAT is a useful method for diagnosing these patients.