[Cross reactivity among proton pump inhibitors: does it exits?].

BACKGROUND: There has been little research into adverse reactions to proton pump inhibitors (omeprazole and its analogs) of suspected allergic etiology. We found nine studies in the medical literature and only two of these describe cross reactivity between proton pump inhibitors detected by skin prick tests.

CASE REPORT: We present a 24-year-old woman who twice developed total body pruritus and urticaria with facial angioedema 1-2 hours after ingesting an omeprazole capsule. In the second episode the patient also reported the sensation of having a lump in her throat.

METHODS: Skin prick and intradermal tests were performed with omeprazole, pantoprazole, and lansoprazole, which were positive for the three proton pump inhibitors. For ethical reasons, oral challenge testing was not performed.

CONCLUSION: The clinical picture and the positive skin test results suggest an IgE-mediated mechanism. Skin prick tests may be useful for the diagnosis of cases of suspected allergy to omeprazole and its analogs. We found cross reactivity between three proton pump inhibitors detected by skin tests.