Management of Hypersensitivity Reactions to Proton Pump Inhibitors: A Retrospective Experience.

BACKGROUND We previously reported perfect specificity and low sensitivity of skin tests in proton pump inhibitor (PPI)-induced immediate hypersensitivity reactions in a prospective multicenter study. Here, in a retrospective study, we aimed to further evaluate the diagnostic workup procedures and characteristics of the patients with suspected PPI hypersensitivity. METHODS This national multicenter study was conducted as a retrospective chart review of patients with a history of PPI-induced immediate hypersensitivity reaction. A total of 60 patients were included. Results of diagnostic workup procedures (standardized skin-prick, intradermal, and oral-provocation tests with PPIs) and the characteristics of the patients were analyzed. RESULTS Lansoprazole was the most commonly suspected drug with 41 patients (68.3%), followed by pantoprazole in 12 patients (20.0%), esomeprazole in 6 (10.0%), rabeprazole in 4 (6.7%), and omeprazole in 1 (1.7%). Anaphylaxis (40 patients, 66.7%) was the most common clinical presentation followed by urticaria (17 patients, 28.3%). Diagnostic skin tests with the culprit PPI were positive in 13/26 patients (50.0%). Diagnostic oral-provocation tests were negative in 6/8 patients; 5 of these 6 patients had skin test results with the culprit PPI, and all were negative. Ten patients had at least 1 cross-reactivity. Extensive cross-reactivity (between >2 PPIs) was detected in 4 patients. CONCLUSIONS Lansoprazole was the most frequently implicated drug and anaphylaxis was the most frequent manifestation of PPI-induced hypersensitivity reactions. Physicians should be aware of the possible cross-reactivity among PPIs; however, a safe, alternative PPI can usually be detected by a thorough drug allergy workup.