ABSTRACT
Anaphylaxis to proton pump inhibitors (PPIs) has rarely been reported. Different patterns of cross-reactivity between PPIs have also been demonstrated using skin tests. Here, we report a case of anaphylaxis to lansoprazole with tolerance to other commercially available PPIs, which was proved by skin tests and oral provocation tests (OPTs). A 47-year-old female patient visited our Emergency Department with a sudden onset of whole body urticaria, facial swelling, dyspnea, and loss of consciousness that developed 1 hour after ingestion of 30 mg of lansoprazole for her episodic epigastric soreness. The skin prick test (SPT) and the intradermal test (IDT) with lansoprazole, esomeprazole, rabeprazole, and pantoprazole were performed. Lansoprazole showed positive reactions in both the SPT (3 mg/mL) and the IDT (0.003 mg/mL). Rabeprazole (3 mg/mL) showed a positive reaction only in IDT. The SPT and the IDT with esomeprazole and pantoprazole were all negative. The OPT with 30 mg of lansoprazole was positive (showing generalized rash and facial swelling 30 minuites after ingestion), while OPTs with esomeprazole, pantoprazole, and rabeprazole were all negative. Other PPIs could be safe alternatives in cases of anaphylaxis to 1 PPI. Skin tests seem to be helpful to define cross-reactivity between PPIs.