D1.380 - Hypersensitivity reactions with proton pump inhibitors: five years of clinical experience

Proton pump inhibitors (PPIs) are generally well tolerated and are frequently prescribed drugs because their risk of adverse effects is 1–3%. Although PPIs have a good safety profile, allergic reactions to these molecules can occur. We aimed to investigate hypersensitivity reactions in patients who underwent oral provocation tests with PPIs in our clinic.

In all, 58 subjects who applied to allergy clinic between January 2018 and December 2023 with a history of early allergic reactions with PPIs and subsequently underwent oral provocation testing to find a diagnostic or safe alternative PPI were included in our study. Information on the subjects' demographic and clinical data and the results of provocation tests was recorded by reviewing patient records.  

Of the 58 subjects included in the study, 44 (75.9%) were females. The mean age of the patients was 54.4 ± 13.8 years. Fifty-three (91.4%) subjects had a history of allergic reactions to a single PPI and 5 (8.6%) subjects had a history of allergic reactions to two different PPIs, such as lansoprazole, pantoprazole, rabeprazole, esomeprazole, and omeprazole. Intradermal skin testing was performed in 51 (87.9%) of the subjects and all were found to be negative. After the provocation test, only two patients (3.4%) developed early-onset hypersensitivity reactions, one with lansoprazole and the other with esomeprazole.

Skin testing is a valuable tool in predicting hypersensitivity reactions associated with PPIs. Although rare, hypersensitivity reactions may occur in patients with negative skin tests.