this group. Although rare, anaphylactic reactions to PPIs have been described. They have modified benzimidazoles with a pyridine ring and chemically related structures A number of case reports suggesting cross-reactivity patterns among lansoprazole and rabeprazole, omeprazole and lansoprazole, and omeprazole and pantoprazole have been reported. Our patient had IgE-mediated anaphylactic or urticarial reactions to lansoprazole, which were confirmed by her history and positive SPT results. However, SPT and IDT were negative for other PPIs including, omeprazole, pantoprazole, esomeprazole and rabeprazole. In addition, the oral challenge test showed that our patient tolerated therapeutic doses of omeprazole, pantoprazole, esomeprazole and rabeprazole. Vovolis reported IgE mediated allergic reaction to rabeprazole with good tolerance to omeprazole and lansoprazole. To the best of our knowledge, our patient is the first reported case of anaphylaxis induced by lansoprazole with good tolerance to other PPIs including rabeprazole. In conclusion, cross-reactivity between PPIs is conflicting. We also showed that controlled oral challenge test using PPIs for which the SPT is negative is a safe approach to choose an alternative drug.