Background: Proton-pump inhibitors (PPI) are one of the most commonly prescribed drugs, and they are generally well tolerated. However, several immediate and delayed hypersensitivity reactions due to PPIs have been reported. Objective: To review the clinical
characteristics and management of immune-mediated immediate and delayed hypersensitivity reactions to PPIs. Methods: We performed a search of a medical literature data base from January 1980 to October 2019 by using keywords that included “proton-pump inhibitors”
and “hypersensitivity.” Results: Anaphylaxis is the most-common clinical presentation in patients with immediate hypersensitivity reactions to PPIs, followed by urticaria and/or angioedema. Occupational contact dermatitis, maculopapular eruption, fixed drug
eruption, symmetrical drug-related intertriginous and flexural exanthema, and severe cutaneous adverse reactions, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms, and acute generalized exanthematous pustulosis have also been reported
with PPIs. Conclusion: The current knowledge and severity of the reported reactions indicated the importance of consideration of a causal relationship between hypersensitivity reactions and PPIs, and awareness of the existence of cross-reactivity among PPIs.
The presence of delayed hypersensitivity reactions in patients toward cellular extracts of their malignant tumors 2.A correlation between the histologic picture of lymphocyte infiltration of the tumor stroma, the presence of such a reaction, and a discussion of the significance of this phenomenon
