Immediate hypersensitivity to iodinated contrast media: diagnostic accuracy of skin tests and intravenous provocation test with low dose

Objective assessment of immediate iodine-based contrast media hypersensitivity reactions using skin and drug provocation testing

BackgroundWith increasing importance of iodine-based contrast media (ICM) in radiology, a label of allergy to ICM has significant impact on patient management, and objective testing for ICM allergy can help guide subsequent administration.PurposeTo correlate skin testing with drug provocation test (DPT) outcomes and determine cross-reactivity between our institution's three available ICMs.Material and MethodsEligible patients who presented to our institution's radiology department within a 3-year period with suspected ICM allergy were referred to the allergist for evaluation with skin testing ± DPT. Patients who tested negative were followed up to evaluate for any reaction after ICM re-exposure in subsequent contrast-enhanced computed tomography scans.ResultsA total of 72 cases underwent testing. Concordance between skin testing and DPT was 85.7% (6/7) for iohexol, 65.1% (28/43) for iodixanol, and 100% (2/2) for iopromide. Cross-reactivity was in the range of 59.6%-75.9% between iohexol and iodixanol, 75.0%-77.4% between iohexol and iopromide, and 43.3%-60.0% between iodixanol and iopromide. Only 1/14 patients who were skin test and DPT negative developed a reaction on re-exposure to ICM after testing.ConclusionObjective testing for ICM hypersensitivity, particularly within 6 months of initial exposure, allows the majority of patients to be administered the same or an alternative ICM with no adverse reaction, with iodixanol having the lowest cross-reactivity.

Hypersensitivity reactions after diagnostic nonvascular administration of iodine-based contrast media and gadolinium-based contrast agents and the role of the drug allergy specialist

The risk of hypersensitivity reactions (HSR) following nonvascular administration of contrast media (CM) for diagnostic studies is very low, likely due to minimal absorption into the systemic circulation. Most published individual cases of HSR after nonvascular CM administration are immediate reactions caused by ionic high-osmolar CM, few by nonionic low-osmolar CM, and none by gadolinium-based contrast agents. Measures to prevent recurrent HSR following nonvascular administration are similar to those recommended to prevent HSR after intravascular CM administration. Premedication as preventive measure has been abandoned, while switching to an alternative CM, preferably based on the results of an allergological analysis, is increasingly advocated. In selected scenarios, preventive measures may be minimized.

Drug provocation tests (DPTs) of contrast media: Useful or not useful? - A narrative review

Drug provocation tests (DPTs) are also used in some patients with a history of a contrast medium (CM)-hypersensitivity reaction. Since the use of contrast agents requires special knowledge that is present in radiology but not necessarily in allergology, this overview should close the knowledge gaps. The literature, and the package inserts of the industry dealing with DPTs in contrast hypersensitivity reactions was analyzed and the results presented. Historical analyses revealed that provocation tests were already done in the past, and called pre-testing. Due to disadvantages, this diagnostic tool was abandoned. A few years later, DPT was introduced as an innovative diagnostic procedure. The DPT has the 3 main disadvantages: a missing standardization, patients at risk (such as compromised renal function) are rarely taken into account, and a negative DPT does not exclude a subsequent CM reaction. DPTs (formerly called pre-testing) are a well-known method for diagnosing CM-related hypersensitivity reactions. Since the disadvantages of this diagnosis outweigh the advantages, we propose replacing DPT with routine contrast-enhanced imaging examination in radiology.

Research progress on desensitization of hypersensitivity reaction to iodinated contrast media

Desensitization therapy for iodinated contrast media (ICM) aims to induce drug tolerance in patients with a history of severe allergic reactions to ICM in a short time. Currently, there is no widely accepted consensus on inducing desensitization to avoid severe allergic responses to ICM. The clinically successful cases have shown that prophylactic use of antihistamines and glucocorticoids can increase the desensitization effect; repeatedly desensitizing and gradually increasing the dose can be conducive to establishing better tolerance to ICM. Most desensitization effects, including stress resistance, can endure 24-48 h. The mechanisms of desensitization therapy remain unclear, the initial dose, administration interval and dose gradient are largely based on clinical experiences and the reaction of patients. This article reviews the current research progress on ICM-related allergies, desensitization methods and related mechanisms, as well as the benefits and hazards of desensitization, to provide a reference for desensitization treatment of hypersensitivity to ICM .

Validation of Practical Pathway in Patients With Anaphylaxis to Low Osmolar Contrast Media: A Retrospective Cohort Study

BACKGROUND

An optimal strategy for choosing safe alternative low osmolar contrast media (LOCM) has not yet been established in patients with a history of LOCM-induced anaphylaxis.

OBJECTIVES

To validate the practical pathway in patients with anaphylaxis to LOCMs and to compare 2 different doses of challenge testing with skin test-negative LOCM.

METHODS

A retrospective cohort study was performed in patients with LOCM-induced anaphylaxis. Patients were challenged with intravenous LOCMs showing negativity in the skin test according to 2 different protocols: low-dose and high-dose (maximum dose 10 and 30 mL, respectively). Challenge-negative LOCMs were selected for use during computed tomography scans, and patients received intravenous pretreatment with 4 mg chlorpheniramine and 40 mg methylprednisolone.

RESULTS

Of the 110 challenge tests, there were 4 (3.6%) positive challenges. Among 106 enhanced computed tomography scans performed using challenge-negative LOCMs, breakthrough reactions occurred in 8 (7.6%). Breakthrough reaction rates were not statistically different between the 2 protocols (8.9% and 6.0% in the low-dose challenge and the high-dose challenge, respectively). Compared with the low-dose protocol, the number needed to test of the high-dose challenge test decreased 2.5-fold. Moreover, none of the patients in the high-dose challenge group incurred severe reactions during computed tomography scans with challenge-negative LOCM, whereas 80% of reactions were severe in the low-dose challenge group.

CONCLUSIONS

We validated a pathway consisting of a battery of skin testing to LOCMs and challenge with skin test-negative LOCM in patients with LOCM-induced anaphylaxis.

Hypersensitivity Reactions to Iodinated Contrast Media

At present, iodinated contrast media (ICM) are mostly non-ionic, have low osmolality, and are safe. Even if adverse drug reactions (ADRs) occur, most are chemo-toxic symptoms and require only observation or H1 antihistamines. However, rare, unpredictable, and even life-threatening hypersensitivity can still occur. The aim of this review is to summarize the issues that all relevant staff need to know about and be able to respond to. The most significant risk factor for ICM hypersensitivity is a history of ICM hypersensitivity. For high-risk populations, we must cautiously weigh the advantages and disadvantages of premedication and be aware that breakthrough reactions may still occur. The best policy for patients with a history of severe ICM hypersensitivity is to avoid the same ICM. If ICM are inevitable, skin tests, in vitro tests, and drug provocation tests may help to find a feasible alternative that is safer. The severity of the hypersensitivity is correlated with the positivity rate of these tests, so there is no need for further investigations for patients with only mild reactions. We should also keep in mind that even excipients in ICM may induce hypersensitivity. Detailed, standardized documentation is essential for correct diagnosis and the prevention of future occurrence.

Contrast Medium Hypersensitivity: A Large Italian Study with Long-Term Follow-Up

Hypersensitivity reactions (HRs) to contrast media (CM) are a major problem. We compared differences of HRs to iodinated contrast media (ICM) versus gadolinium-based contrast media (GBCM), collecting data on prevalence, type, latency and severity. Secondly, the predisposition to perform new contrast tests, use of premedication and possible appearance of new reactions were explored in a long-term follow-up of 5 years. Clinical data, comorbidities, skin test (ST) results, re-exposure to CM procedures with any new reactions, premedication and CM used were collected. In a retrospective single-center study, 350 patients with mild to moderate HRs were enrolled. Asthma, food allergy, non-allergic drug hypersensitivity and neurologic disease were significantly more frequent in patients with HRs to GBCM compared to the high evidence of cardiovascular disease and history of cancer in patients with HRs to ICM. A marked delay in performing STs was reported by patients with negative results (66 months, p < 0.01). Iomeprol, iopamidol and gadobenic acid were the culprit CM most involved in HRs in patients with positive STs. During follow-up, 7.1% of responders reported new HRs to CM despite negative STs, premedication and infusion of alternative CM in most cases.

Lidocaine: A Local Anesthetic, Its Adverse Effects and Management

The most widely used medications in dentistry are local anesthetics (LA), especially lidocaine, and the number of recorded adverse allergic responses, particularly of hazardous responses, is quite low. However, allergic reactions can range from moderate to life-threatening, requiring rapid diagnosis and treatment. This article serves as a review to provide information on LA, their adverse reactions, causes, and management.

Assessment of immediate and non-immediate hypersensitivity contrast reactions by skin tests and provocation tests: A review

INTRODUCTION

Allergic and nonallergic hypersensitivity reactions to iodinated contrast media (ICM) and gadolinium-based contrast media are classified as immediate or non-immediate hypersensitivity reactions (IHR and NIHR), respectively. Skin tests and provocation tests are recommended for the evaluation of hypersensitivity reactions to contrast agents; however provocations are not common in clinical practice.

METHODS

A MEDLINE search was conducted to investigate studies comprising both skin tests and provocation tests that evaluated hypersensitivity reactions to ICM.

RESULTS

Nineteen studies were identified that reported on skin tests, followed by provocations. In the case of IHR to ICM, 65/69 (94%) patients with a positive skin test for the culprit media tolerated a challenge with a skin-test-negative alternative ICM. In IHR to ICM with a negative skin test for the culprit media, provocations were positive in 3.2%-9.1% patients. In the case of a NIHR to ICM with a positive skin test, provocation with a skin-test-negative agent was tolerated in 75/105 (71%) of cases. In NIHR with a negative skin test for the culprit agent, re-exposure to the culprit or an alternative was positive in 0%-34.6% patients. Provocations with the same ICM in skin test positive patients with IHR or NIHR were positive for a majority of the patients, although such provocation tests were rarely performed. Data on hypersensitivity reactions, skin tests and provocations with gadolinium-based contrast media were limited; however, they exhibited a pattern similar to that observed in ICM.

CONCLUSION

In both ICM and gadolinium-based contrast media, the risk of an immediate repeat reaction is low when skin tests are negative. In contrast, a provocation with a skin-test-positive contrast medium showed a high risk of an immediate repeat hypersensitivity reaction. Therefore, a thorough medical history is necessary, followed by skin tests. A provocation is recommended, for diagnostic work-up, when the diagnosis is uncertain.

Oral premedication in patients with a history suggesting hypersensitivity to iodinated contrast media

Introduction

Iodinated contrast media (ICM) are pharmaceuticals widely used in diagnostic procedures. Adverse effects associated with their administration are quite frequent and mostly mild. However, they raise concerns in patients and doctors in the context of their future use.

Aim

To determine efficacy of premedication before medical procedures with the use of iodinated contrast media in patients with a history suggesting a hypersensitivity reaction after their past use.

Material and methods

Out of 152 patients consulted due to adverse reactions after ICM (85 women and 67 men, aged 43–90), 101 were selected with the history suggesting a mild hypersensitivity reaction (urticaria, itching, skin redness, malaise etc.). All the patients had health problems requiring a procedure with ICMadministration in the near future. The premedication was given with cetirizine (10 mg) and prednisone (20 mg or 50 mg, randomly assigned) 13, 7 and 1 h before the ICM administration. Presence of adverse events was compared between the subgroups with χ² test and efficacy of premedication – with Wilcoxon test.

Results

Seventy-six patients underwent the radiologic procedure with premedication with antihistamine and a lower (40 patients) or higher dose (36 patients) of prednisone. Four of them reported a cutaneous hypersensitivity reaction (urticaria, itching, redness) and one – dyspnoea. There was no statistically significant difference in relation to the premedication protocol (p = 0.1306).

Conclusions

Premedication with cetirizine and prednisone before radiologic procedures proved to be efficient in patients with a history suggesting hypersensitivity to iodinated contrast media. There was no significant difference in efficacy related to the dose of prednisone (20 mg vs. 50 mg).

Hypersensitivity Reactions to Multiple Iodinated Contrast Media

The incidence of hypersensitivity reactions (HSRs) to iodinated contrast media (ICM) has risen over last years, representing an important health problem. HSRs to ICMs are classified into immediate reactions (IRs) and non-immediate reactions (NIRs) according to if they occur within 1 h or longer after ICM administration. The diagnosis of HSRs to ICM is complex as skin test (ST) sensitivity ranges widely, and drug provocation test (DPT) protocols are heterogeneous. In this manuscript, we describe the clinical characteristics of a series of patients confirmed as HSR to ICM and the diagnosis procedure carried out, looking into those cases confirmed as HSRs to multiple ICMs. For this purpose, we prospectively evaluated patients suggestive of HSRs to ICMs and classified them as IRs or NIRs. STs were carried out using a wide panel of ICMs, and in those with a negative ST, a single-blind placebo controlled DPT was performed with the culprit. If ST or DPT were positive, then tolerance was assessed with an alternative negative ST ICM. We included 101 cases (12 IRs and 89 NIRs) confirmed as allergic. Among them, 36 (35.64%) cases were allergic to more than one ICM (8 IRs and 28 NIRs). The most common ICM involved were iomeprol and iodixanol. Although not statistically significant, the percentage of patients reporting anaphylaxis was higher in patients allergic to multiple ICMs compared with patients allergic to a single ICM (50 vs. 25%). Likewise, the percentage of positive results in STs was higher in patients allergic to multiple ICMs compared with those allergic to a single ICM (for IR 62.5 vs. 25%, p > 0.05; and for NIR, 85.71 vs. 24.59%, p < 0.000). In cases allergic to more than one ICM, DPT with negative-ST ICM was positive in more than 60% (24/36) of cases. Therefore, allergy to multiple ICMs is common, associated to severe reactions in IRs, and confirmed frequently by positive STs. The allergological work-up should include DPT not only to establish the diagnosis but also to identify safe alternative ICM, even if ICM is structurally unrelated and ST is negative. More studies are needed to clarify mechanisms underlying cross-reactivity among ICMs.

SIRM-SIAAIC consensus, an Italian document on management of patients at risk of hypersensitivity reactions to contrast media

Hypersensitivity reactions (HRs) to contrast media (CM) can be distinguished in immune-mediated (including allergic reactions) and non-immune-mediated reactions, even if clinical manifestations could be similar. Such manifestations range from mild skin eruptions to severe anaphylaxis, making it important for radiologists to know how to identify and manage them. A panel of experts from the Società Italiana di Radiologia Medica e Interventistica (SIRM) and the Società Italiana di Allergologia, Asma e Immunologia Clinica (SIAAIC) provided a consensus document on the management of patients who must undergo radiological investigations with CM. Consensus topics included: the risk stratification of patients, the identification of the culprit CM and of a safe alternative by an allergy workup, as well as the use of premedication and the correct procedure to safely perform an elective (i.e., scheduled) or urgent examination. The most important recommendations are: (1) in all patients, a thorough medical history must be taken by the prescribing physician and/or the radiologist to identify at-risk patients; (2) in patients with hypersensitivity reactions to CM, the radiologist must consider an alternative, non-contrast imaging study with a comparable diagnostic value, or prescribe a different investigation with another class of CM; (3) if such options are not feasible, the radiologist must address at-risk patients to a reference centre for an allergy evaluation; (4) if timely referral to an allergist is not viable, it is recommended to use a CM other than the responsible one, taking into account cross-reactivity patterns; in the case of patients with histories of severe reactions, the presence of an anesthesiologist is also recommended and a premedication is suggested.

Subsequent MRI of pediatric patients after an adverse reaction to Gadolinium-based contrast agents

Background

Gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance imaging (MRI) scans often must be used repeatedly in pediatric oncologic patients. Although GBCAs are usually well tolerated, severe and life-threatening allergic reactions might occur, which can result in overly cautions adherence to special precautions in patients.

Purpose

To evaluate the management of the reported GBCA-associated adverse reactions in subsequent contrast-enhanced MRIs in pediatric patients, distinguishing non-allergic and allergic reactions.

Materials and methods

In this retrospective, cross-sectional study, consecutive pediatric neurooncological patients who underwent GBCA-enhanced MRI at our university hospital, between 2007 and 2016, were eligible. The patients’ history was evaluated with regard to any adverse events after GBCA administration. In a subset of patients with reported adverse reactions, the institutional premedication regime or an allergy work-up in clinical practice were performed, using either skin-prick tests or intravenous provocation tests in a double-blind procedure.

Results

Included were 8156 contrast-enhanced MRI scans in 2109 patients. Nineteen acute adverse events (19/8156; 0.23%) in 17 patients (17/2109; 0.81%) were reported. Despite a premedication regime in 14 patients, three patients (3/14; 21.4%) reported a breakthrough reaction. None of the 12 patients who underwent skin-prick tests or intravenous provocation tests showed allergic reactions. At least one well-tolerated GBCA was identified in almost every tested patient.

Conclusion

A fast-track allergy work-up can help to distinguish non-allergic and allergic reactions and to identify a well-tolerated GBCA, thus avoiding unnecessary premedication for subsequent GBCA administrations.

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.

Adverse reactions during procedures: Hypersensitivity to contrast agents and dyes

OBJECTIVE

This review provides an overview of the literature on hypersensitivity reactions during procedures to commonly used contrast agents and dyes. A synthesis of current knowledge on clinical symptoms, epidemiology and risk factors, pathomechanism, and management of hypersensitivity reactions to these substances is presented.

DATA SOURCES

A literature search was conducted through Medline. Included were peer-reviewed articles written in English between 2000 and 2019.

STUDY SELECTIONS

Relevant clinical studies, experimental studies, and review articles have been selected. Additionally, case reports have been included if they carried significant information about rare clinical forms of hypersensitivity reactions, disease mechanisms, or therapy.

RESULTS

An allergological workup is only indicated for patients with a history of immediate (IHR) and nonimmediate hypersensitivity reactions (NIHR) but not for toxic or unrelated adverse events. Skin tests with or without experimental cellular laboratory tests in patients with previous reactions can provide evidence for an allergic mechanism. Positive skin tests indicating allergy are more common in severe reactions. If the adverse event was allergic, skin testing of alternatives is helpful for the selection of other contrast agents for future procedures. Premedication alone may be insufficient in these cases, and breakthrough reactions occur. For nonallergic reactions, change of contrast agent and premedication is often but not always sufficient to suppress reactions.

CONCLUSION

Patients with previous NIHR or IHR, especially moderate and severe IHR, needing potential re-administration of contrast agents should be skin tested to identify an allergic mechanism as well as alternative agents to be used for future procedures.

Patients with a history of hypersensitivity reaction to iodinated contrast medium and given iodinated contrast during an interventional pain procedure

In patients with a history of a hypersensitivity reaction to iodinated contrast medium, iodinated contrast medium is avoided, antihistamine and steroid premedication are given, or a gadolinium-based contrast agent is employed. Six patients with a history of a hypersensitivity reaction to iodinated contrast medium and who were not premedicated had an unintentional injection of iodinated contrast. None of the patients developed a moderate or severe reaction. All patients had gadopentetate dimeglumine in one of their injections; three had repeated injections of the gadopentetate. The lack of a significant reaction may be due to any or all of the following: questionable history of iodinated contrast reaction, low dose of iodinated contrast given, concomitant injection of (epidural) steroid, and slower absorption from epidural compared with intravenous injection. While it is reassuring to know that there is a low possibility of a moderate to severe reaction in these patients, every effort should be made to avoid this scenario, appropriate drugs and resuscitation equipment should be immediately available, and the patients should be observed adequately and followed for the possibility of late reactions. Recent publications have called for caution in the use of gadolinium-based contrast agents.

Immediate Hypersensitivity to Contrast Agents: The French 5-year CIRTACI Study

BACKGROUND

Iodinated and gadolinium-based contrast media (ICM; GBCM) induce immediate hypersensitivity (IH) reactions. Differentiating allergic from non-allergic IH is crucial; allergy contraindicates the culprit agent for life. We studied frequency of allergic IH among ICM or GBCM reactors.

METHODS

Patients were recruited in 31 hospitals between 2005 and 2009. Clinical symptoms, plasma histamine and tryptase concentrations and skin tests were recorded. Allergic IH was diagnosed by intradermal tests (IDT) with the culprit CM diluted 1:10, "potentially allergic" IH by positive IDT with pure CM, and non-allergic IH by negative IDT.

FINDINGS

Among 245 skin-tested patients (ICM = 209; GBCM = 36), allergic IH to ICM was identified in 41 (19.6%) and to GBCM in 10 (27.8%). Skin cross-reactivity was observed in 11 patients with ICM (26.8%) and 5 with GBCM (50%). Allergy frequency increased with clinical severity and histamine and tryptase concentrations (p < 0.0001). Cardiovascular signs were strongly associated with allergy. Non-allergic IH was observed in 152 patients (62%) (ICM:134; GBCM:18). Severity grade was lower (p < 0.0001) and reaction delay longer (11.6 vs 5.6 min; p < 0.001). Potentially allergic IH was diagnosed in 42 patients (17.1%) (ICM:34; GBCM:8). The delay, severity grade, and mediator release were intermediate between the two other groups.

INTERPRETATION

Allergic IH accounted for < 10% of cutaneous reactions, and > 50% of life-threatening ones. GBCM and ICM triggered comparable IH reactions in frequency and severity. Cross-reactivity was frequent, especially for GBCM. We propose considering skin testing with pure contrast agent, as it is more sensitive than the usual 1:10 dilution criteria.

Developments in the field of allergy in 2016 through the eyes of Clinical and Experimental Allergy

In this article, we described the development in the field of allergy as described by Clinical and Experimental Allergy in 2016. Experimental models of allergic disease, basic mechanisms, clinical mechanisms, allergens, asthma and rhinitis, and clinical allergy are all covered.

Immediate reactions to iodinated contrast media

BACKGROUND

Immediate hypersensitivity reactions (IHRs) to iodinated contrast media (ICMs) remain a common clinical concern. Positive skin test and basophil activation test results suggest a specific IgE-mediated mechanism in some cases. Skin test and controlled challenge test (CCT) are useful to manage these patients.

OBJECTIVE

To study clinical and allergologic features of IHRs to ICMs in a Spanish tertiary hospital during a 7-year period.

METHODS

Demographic and clinical data concerning the reaction were recorded. Patients treated at the Allergy Department of Hospital General Universitario Gregorio Marañón, Madrid, Spain, underwent skin tests. In those with positive results, CCTs with an alternative skin-test-negative ICM was performed. Global reaction rate was calculated and compared for each ICM.

RESULTS

A total of 342 reactions occurred in 329 patients. Cutaneous symptoms were the most common (87.7%). A total of 196 patients underwent an allergy workup, 15 (7.6%) of whom had positive skin test results. Reactions were more severe in patients with positive vs negative skin test results (grade 1, 46.7% vs 73.6%; grade 2, 33.3% vs 20.9%; grade 3, 20% vs 5.46%; P < .05). Three patients had cross-reactivity to 3 ICMs, all including ioversol and iomeprol. Six patients allergic to iopamidol tolerated ioversol and 1 tolerated iomeprol. Four patients allergic to ioversol and 1 allergic to iomeprol tolerated iopamidol. The global reaction rate was 0.2%, differing for each ICM (iopamidol, 0.14%; ioversol, 0.2%; and iomeprol, 0.4%; P < .001). Positive skin test results were found in a low percentage of patients in whom skin test-based CCT identified an alternative non-cross-reactive ICM. Low-grade cross-reactivity was found, especially between iopamidol and ioversol. Reactions were more severe in patients with positive skin test results. The reaction rate was greater for iomeprol compared with iopamidol (reaction rate, 2.8%) and ioversol (reaction rate, 2%).

CONCLUSION

This study identified a possible underlying specific IgE-mediated mechanism by positive skin test result in a low percentage of patients with IHRs to ICMs. In these patients, the CCT based on skin test results was useful for identifying an alternative non-cross-reactive ICM. More studies are needed to investigate the underlying mechanism in patients with IHRs and negative skin test results.

Pro and Contra: Provocation Tests in Drug Hypersensitivity

Drug provocation test (DPT) is the controlled administration of a drug to diagnose immune- or non-immune-mediated drug hypersensitivity and the last step for accurate recognition of drug hypersensitivity reactions when the previous diagnostic evaluations are negative or unavailable. A DPT is performed only if other conventional tests fail to yield conclusive results. In each clinical presentation, "to provoke or not to provoke" a patient should be decided after careful assessment of the risk-benefit ratio. Well-defined benefits of DPT include confirmative exclusion of diagnoses of drug hypersensitivity and provision of safe alternatives. However, disadvantages such as safety, difficulty in interpretations of results, lack of objective biomarkers, risks of resensitization, efficiency in daily practice, and lack of standardized protocols, are poorly debated. This review summarizes the current published research concerning DPT, with particular emphasis on the advantages and disadvantages of DPT in an evidence-based manner.