Anaphylaxis to omeprazole. Cross-reactivity with the other proton pump inhibitors

Hypersensitivity reactions to proton pump inhibitors. An EAACI position paper

Proton pump inhibitors (PPIs) are invaluable therapeutic options in a variety of dyspeptic diseases. In addition to their well-known risk profile, PPI consumption is related to food and environmental allergies, dysbiosis, osteoporosis, as well as immediate and delayed hypersensitivity reactions (HSRs). The latter, although a rare event, around 1%-3%, due to the extraordinarily high rate of prescription and consumption of PPIs are related to a substantial risk. In this Position Paper, we provide clinicians with practical evidence-based recommendations for the diagnosis and management of HSRs to PPIs. Furthermore, the unmet needs proposed in the document aim to stimulate more in-depth investigations in the topic.

PPI adverse drugs reactions: a retrospective study

Proton pump inhibitors (PPIs) are drugs capable of blocking the gastric pump H,K-ATPase in order to inhibit gastric acid secretion. Omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole belong to PPIs category. Although PPIs have a good safety profile, allergic reactions to these molecules can occur. The real rate of hypersensitive reactions to PPIs is unknown. The aim of this retrospective study is to evaluate the rate of hypersensitive reactions to PPIs in patients admitted to our Unit between 2008 and 2013 with a history of drug hypersensitivity. From a database of 1229 patients (921 women, 308 men) with adverse drug reaction we extrapolated the data about PPI reactions. Twelve patients (10 female, 2 men) had a positive history for hypersensitive reaction to PPI. Pantoprazole was the most frequently PPI involved. Based on patient personal history in some cases we performed an oral challenge test for an alternative anti-acid drug and none of them had adverse reactions. According to our experience and according to the literature and pharmacovigilance reports, ADR caused by PPIs are ever increasing. Adverse reactions to these drugs are still under-reported; however, considering the frequency of their prescription worldwide, the risk of severe allergic events is low. Further studies are needed to provide clearer data on the real incidence and prevalence about this matter. This should be useful to help physician in choosing the molecule to prescribe and, in case of hypersensitivity, the alternative molecule to test, also considering the possible cross-reactivity.

Rare drug allergies: Review on prevalence and test procedures

This paper gives a review on rare hypersensitivity reactions (including allergies) to drugs. Pathogenesis, allergy tests and possible therapeutic options are discussed by presenting examples out of the following group of drugs: antiinfectious (i.e. chinolones, telaprevir), oncological (i.e. platin-based cytostatics), immunologic (i.e. cetuximab, omalizumab), others (i.e. glucocorticosteroids). Usually there is no standardized allergologcial work-up procedure. Testing must therefore take into consideration previous experiences from other authors and on general recommendations.

Immediate and Delayed Hypersensitivity Reactions to Proton Pump Inhibitors: Evaluation and Management

PPIs are among the most commonly administered medications in the USA and are generally well tolerated. Immediate and delayed immune-mediated hypersensitivity reactions are rare but increasingly recognized adverse effects of proton pump inhibitors (PPIs). Immediate hypersensitivity reactions can occur due to IgE-mediated hypersensitivity to PPIs and can be evaluated by immediate hypersensitivity skin testing and oral provocation challenge testing. A desensitization protocol can be used when PPI use cannot be avoided in an allergic patient. Delayed hypersensitivity reactions to PPIs have also been reported. Occupational exposures causing cutaneous reactions to PPIs are the most commonly reported delayed hypersensitivity reaction, followed by drug-induced subacute cutaneous lupus erythematosus. This review presents a summary of the clinical presentation, diagnostic evaluation, and management of immune-mediated hypersensitivity reactions to PPIs.

Evaluation and management of hypersensitivity to proton pump inhibitors

OBJECTIVE

Proton pump inhibitors (PPIs) are widely used for the treatment of gastroesophageal reflux disease and peptic ulcer disease. PPIs are well tolerated, but they can cause hypersensitivity reactions (HSRs). Although simply avoiding a PPI after an HSR is appropriate for most patients, there are clinical scenarios that require treatment with a PPI.

DATA SOURCES

A comprehensive literature review was performed to propose an evidence-based approach to the evaluation and management of HSRs to PPIs.

STUDY SELECTIONS

Articles from June 1986 through September 2012 on PPI hypersensitivity were reviewed. Thirty-nine studies that met the search criteria were included in the review. HSRs to PPIs and skin testing protocols used to evaluate HSRs were analyzed from the 39 identified publications. For each case, the culprit drug and dose, the age and sex of the patient, and the symptoms and timing of the HSR were recorded. HSRs were classified into immune- or nonimmune-mediated categories.

RESULTS

A total of 118 cases of immune-mediated HSRs to 5 PPIs were identified, most of which were suspected IgE-mediated HSRs. Omeprazole was the culprit PPI most frequently associated with HSRs. The most common clinical manifestations of PPI HSRs were cutaneous reactions. Nonirritating concentrations for skin prick and intradermal testing were identified. Skin testing showed variable cross-reactivity patterns among the different PPIs.

CONCLUSION

The HSRs to PPIs should be formally investigated, especially when reasonable alternative therapies do not exist. The reviewers propose an evidence-based algorithm for evaluating and managing patients with an HSR to a PPI.

Immediate-type hypersensitivity reactions to proton pump inhibitors: usefulness of skin tests in the diagnosis and assessment of cross-reactivity

BACKGROUND

Data are limited about the value of skin tests in the diagnosis of proton pump inhibitor (PPI)-induced hypersensitivity reactions and the cross-reactivity between PPIs. We aimed to assess the role of skin testing in the diagnosis of PPI-related immediate hypersensitivity reactions and the cross-reactivity patterns among PPIs.

METHODS

The study was designed in a prospective, national, multicentre nature. Sixty-five patients with a suggestive history of a PPI-induced immediate hypersensitivity reaction and 30 control subjects were included. Standardized skin prick and intradermal tests were carried out with a panel of PPIs. Single-blind, placebo-controlled oral provocation tests (OPTs) with the PPIs other than the culprit PPI that displayed negative results in skin tests (n = 61) and diagnostic OPTs with the suspected PPI (n = 12) were performed.

RESULTS

The suspected PPIs were lansoprazole (n = 52), esomeprazole (n = 11), pantoprazole (n = 9), rabeprazole (n = 2), and omeprazole (n = 1). The sensitivity, specificity, and negative and positive predictive values of the skin tests with PPIs were 58.8%, 100%, 70.8%, and 100%, respectively. Fifteen of the 31 patients with a hypersensitivity reaction to lansoprazole had a positive OPT or skin test result with at least one of the alternative PPIs (8/52 pantoprazole, 6/52 omeprazole, 5/52 esomeprazole, 3/52 rabeprazole).

CONCLUSION

Considering the high specificity, skin testing seems to be a useful method for the diagnosis of immediate-type hypersensitivity reactions to PPIs and for the evaluation of cross-reactivity among PPIs. However, OPT should be performed in case of negativity on skin tests.

Hypersensitivity reactions to proton pump inhibitors

PURPOSE OF REVIEW

Proton pump inhibitors (PPI) are one of most frequently prescribed drugs in the world. The purpose of this review is to describe the hypersensitivity reactions to PPI.

RECENT FINDINGS

Hypersensitivity reactions to PPI vary from mild symptoms to life-threatening disorders. Cases of urticaria, angioedema, anaphylaxis, cytopenia, vasculitis, acute allergic interstitial nephritis, occupational contact dermatitis, photoallergic dermatitis, maculopapular eruption, erythroderma, Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome, Stevens-Johnson syndrome/toxic epidermal necrolysis, and other autoimmune reactions (including cutaneous lupus erythematosus) have been described.

SUMMARY

A high level of clinical suspicion is critical in the diagnosis of PPI-induced hypersensitivity reactions. Physicians should be aware of the possible hypersensitivity reactions due to PPI and routine/empirical prescription for PPI should only be used when clinically indicated.