Iodinated Contrast Media Hypersensitivity Research Articles

Intradermal testing of iodinated contrast media: Should we test up to pure or with diluted compounds only?

Intradermal testing (IDT) with iodinated contrast media (ICMs) is an established diagnostic tool in patients with ICM hypersensitivity. Currently, it is unclear which test concentration is the more useful one, up to pure or up to 1:10 diluted ICMs. We searched the literature database PubMed for eligible papers dealing with ICM allergy and their IDT results. We analyzed the data presented by the papers and compared the pooled groups tested with diluted and undiluted ICMs. We identified 29 eligible original papers, and extracted data of 1137 patients that formed the study population. Although in the cohort tested with diluted ICMs the number of tested ICMs was greater, the percentage of positive tests was significantly less (9.0% vs. 24.7%; P < 0.0001; OR 0.30 [0.26-0.34]). The frequency of positive tested culprit ICMs was also lesser in the group tested with diluted ICMs (31.0% vs. 72.5%; P < 0.0001; OR 0.17 [0.12-0.23]). The number of drug provocation tests (DPTs) was greater in patients with diluted IDTs (374 vs. 89; P < 0.0001; OR 2.54 [1.93-3.36]). We detected an increased sensitivity in patients with undiluted tests (0.774 vs. 0.282) and a nearly identical specificity in both groups (1 vs. 0.983). For the first time, we show that IDT up to pure ICM concentrations is superior to using diluted ICMs only. Possibly, we can reduce the number of DPTs when performing IDTs with pure ICMs. In the undiluted group, there were no hints for skin irritations or unspecific test reactions.

Bridging the gap between bench and clinic: the importance of understanding the mechanism of iodinated contrast media hypersensitivity.

Since the advent of CT, iodinated contract media (ICM) has become one of the most regularly administered intravenous medications in clinical settings. Although considered generally safe, ICM is one of the most common causes of adverse drug reactions in clinical practice, accounting for more than 2 million adverse reactions worldwide. Currently, there are few useful tools to diagnose patient hypersensitivity, with the major limitation being the lack of consensus regarding the mechanisms of hypersensitivity to ICM. While there is an overwhelming abundance of literature pertaining to clinical features including incidence, symptomatology, and risk, few studies have further investigated the underlying mechanisms behind their clinical observations. Of the available literature discussing pathophysiology, most primary studies were completed over 20 years ago, since which the molecular characteristics of ICM have changed. Furthermore, many reviews mentioning pathophysiology fail to adequately emphasize the clinical importance of understanding the molecular pathways involved in hypersensitivity. In this review, we aim to emphasize the clinical relevance of pathophysiology as it relates to the prediction and diagnosis of hypersensitivity reactions to ICM. To this end, we will first briefly characterize hypersensitivity reactions to ICM with respect to epidemiology and clinical presentation. We will then present the existing evidence supporting various proposed mechanisms of hypersensitivity, highlighting the gaps that remain in the mechanistic delineation of both immediate and delayed reactions. Finally, we discuss the possibility of in vitro testing as a way to predict and diagnose hypersensitivity reactions, pending a more complete elucidation of mechanisms.

Iodinated Contrast Media Substitution to Prevent Recurrent Hypersensitivity Reactions: A Systematic Review and Meta-Analysis.

Background Changing iodinated contrast media (ICM) may reduce the risk of recurrent ICM-induced hypersensitivity reactions in patients with a prior reaction. Purpose To perform a systematic review on the effectiveness of ICM change in comparison with no change to prevent recurrent ICM immediate hypersensitivity reactions. Materials and methods Multiple data bases were searched without language restriction between January 1990 and August 2021 to identify comparative studies of any design that included patients with a prior ICM hypersensitivity reaction to low-osmolality ICM and re-exposure to intravascular ICM. The methods used included a duplicate assessment of eligibility, double extraction of quantitative data, validity assessment, and random-effects meta-analysis. The primary outcome was the incidence of all-grade immediate recurrent hypersensitivity reactions. Secondary outcomes were the incidence of severe immediate recurrent hypersensitivity reactions and other adverse events associated with ICM change. Results Six retrospective observational studies at moderate to severe risk of bias assessed 7155 adult patients (4329 in the ICM change group and 2826 in the no-change group). Studies adopted nonstandardized switching methods, and the proportions of the ICM change group ranged between 19% (five of 27 examinations) and 80% (3104 of 3880 examinations). A Bayesian meta-analysis revealed that changing ICM was associated with a reduced risk of recurrent hypersensitivity reaction by 61% (risk ratio = 0.39; 95% credible interval [CrI]: 0.24, 0.58). The wide-ranging estimates of risk reduction were not explained by the risk of bias ratings, the event rates in the no-change group, the index-reaction severity, or the co-administered nonstandard premedication. Rare severe recurrent reactions (five studies with five events) precluded a conclusion (risk ratio = 0.34, favoring ICM change; CrI: 0.01, 3.74). Adverse events associated with ICM change were not reported. Conclusion In observational evidence of limited quality, iodinated contrast media (ICM)-change was associated with a reduced risk of recurrent immediate hypersensitivity reaction in patients with a prior ICM-induced hypersensitivity reaction. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by McDonald in this issue.

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.

Practice parameters for diagnosing and managing iodinated contrast media hypersensitivity.

Immediate and nonimmediate hypersensitivity reactions to iodinated contrast media (ICM) have been reported to occur in a frequency of about 0.5%-3% of patients receiving nonionic ICM. The diagnosis and management of these patients vary among guidelines published by various national and international scientific societies, with recommendations ranging from avoidance or premedication to drug provocation test. This position paper aims to give recommendations for the management of patients with ICM hypersensitivity reactions and analyze controversies in this area. Skin tests are recommended as the initial step for diagnosing patients with immediate and nonimmediate hypersensitivity reactions; besides, they may also help guide on tolerability of alternatives. Re-exposition or drug provocation test should only be done with skin test-negative ICMs. The decision for performing either re-exposition or drug provocation test needs to be taken based on a risk-benefit analysis. The role of in vitro tests for diagnosis and pretreatment for preventing reactions remains controversial.

Absence of Iodinated Contrast Hypersensitivity and Characterization of Gadolinium Utilization in an Interventional Pain Population.

Iodinated contrast media (ICM) allergy labels pose a unique clinical problem for the interventional pain physician due to the drawbacks of gadolinium for enhancement during pain procedures, as well as the reluctance to add to the cumulative steroid burden with steroid premedication. However, the risks of ICM hypersensitivity specific to this setting have not been previously described. We aimed to describe the incidence of ICM-induced hypersensitivity during the performance of epidural injections in a large healthcare system. We also sought to characterize preexisting ICM allergy labels and how these affected consequent gadolinium utilizations in this population. 6,471 epidural pain procedures requiring contrast enhancement were performed during the 18-month study period. There were no reported contrast-induced hypersensitivity reactions in this time. 108 patients (1.6%) had a preexisting ICM allergy; a shellfish/seafood allergy was recorded in 118 patients (1.82%), and 51 charts (0.78%) were labeled with "iodine" allergy. 183 individuals received gadolinium for enhancement during epidural steroid injections. 96.7% of gadolinium utilization occurred in the context of preexisting allergy labels in the electronic medical record. Of note, 20 patients (18.5%) with ICM allergy labels also received iodinated contrast, and this was uneventful in all cases. Our results suggest that ICM-associated hypersensitivity is very rare during epidural procedures and the incidence is significantly lower than expected based on reaction rates during intravascular administration. This may be related to both dose as well as route of administration. The establishment of a protocol for safe workup of ICM allergy labels would be useful in optimizing pain procedures.

Recent updates of iodinated contrast media hypersensitivity

Previously, immediate reactions to ionic high-osmolar iodinated contrast media (ICM) were regarded as nonimmunological. How ever, despite the use of lower-osmolar ICM, ICM hypersensitivity still occurs in some patients and recent studies suggest that there would be a true allergic response, especially in more severe form. Currently, it is important to identify the sensitized ICM and avoid the agent; however, the usefulness of skin tests and challenge tests has not yet been established, since there are few large-scale studies on them. Although, skin test-negative ICM can be safely used in clinical practice, conflicting results have been reported through various studies, depending on the challenge protocols used. Therefore, standard protocols need to provided. Even if a cul prit agent is not proven by skin tests, its use should be avoided. Reuse of contrast media increases the risk of occurrence of hyper sensitivity reactions. For patients with previous hypersensitivity reactions to contrast media, premedication can help prevent recur rence, but breakthrough in hypersensitivity is not fully achieved by premedication, especially when the previous reaction was a se vere form such as anaphylaxis. Therefore, it is necessary to establish an optimal strategy to choose alternative ICM and premedica tion protocols to prevent recurrence of hypersensitivity reactions to nonionic contrast media. (Allergy Asthma Respir Dis 2020;8:107-113)

Diagnostic procedures & practices in drug allergy/hypersensitivity: a survey of 13 Asian countries.

BackgroundThe issues and challenges in the diagnosis of drug allergy/hypersensitivity among children and adults in Asia are likely to be different from non-Asian countries.ObjectiveTo study the diagnostic modalities used in the evaluation and management of drug allergy/drug hypersensitivity reactions (DHRs) among member societies of the Asia Pacific Association of Allergy, Asthma and Clinical Immunology (APAAACI).MethodsA questionnaire comprising 41 questions was circulated electronically to member societies and individual members of APAAACI between January 23, 2020 and March 6, 2020.ResultsTwenty-six respondents from 15 member societies and 1 individual member responded. European DHR guidelines were most commonly used. Skin prick and intradermal testing was used by 100%, with only 60% having access to commercial penicillin skin test reagents. In vitro-specific IgE tests were used by 75%, and basophil activation test by 56.3% for immediate DHR. Patch tests were used by 75% in contrast to lymphocyte transformation tests by 25% for nonimmediate DHR. Drug provocation tests were used by 68.8%, the most common indication being to exclude hypersensitivity where history/symptoms were not suggestive of drug hypersensitivity/allergy (93.3%). Human leukocyte antigen (HLA) genotype testing was mandatory among 25% respondents before new carbamazepine prescriptions, and 8.3% for allopurinol prescriptions.ConclusionsThere was increased use of skin testing for iodinated contrast media hypersensitivity and patch testing for nonimmediate DHR. HLA genotype testing prior to new carbamazepine, allopurinol and abacavir prescriptions remain variable despite strong associations for severe cutaneous adverse reactions with Asian ethnicity. Results of this survey form a useful framework for developing educational and training needs and for improving access to drug allergy diagnostic and treatment modalities across APAAACI member societies.

Impact of short term oral steroid use for intravenous contrast media hypersensitivity prophylaxis in diabetic patients undergoing nonemergent coronary angiography or interventions.

Oral steroids are routinely administered in the United States for prophylaxis of iodinated contrast media hypersensitivity (ICMH). We studied the impact of short-term steroid use in diabetic patients with ICMH undergoing nonemergent coronary angiography. We retrospectively analyzed records of diabetic patients with and without ICMH who underwent nonemergent coronary angiography at our center. Primary study endpoint was 30-day major adverse cardiac events (MACE) and secondary endpoints were pre- and postprocedure fasting blood glucose (FBG), highest in hospital blood glucose, pre- and postprocedure systolic blood pressure (SBP), and use of intravenous insulin and antihypertensive medications. A total of 88 diabetics with ICMH (study group) and 76 diabetics without ICMH (control group) undergoing angiography were enrolled. Demographics and hemoglobin A1c values were similar in both groups. Preprocedural FBG was significantly higher in the study group. The study group had significantly higher post angiography FBG (239.93 + 96.88 mg/dl vs. 156.6 + 59.88 mg/dl) and greater use of intravenous (IV) insulin (67.27% vs. 32.43%). Further, those who received steroids had significantly higher systolic SBP postprocedure (146.16 + 25.35 mmHg vs. 130.8 + 21.59 mmHg), a higher incidence of severe hypertension and use of IV antihypertensive medications (80.95% vs. 19.05%) periprocedurally. There were no differences in 30-day MACE between groups. Short-term steroid use for ICMH results in a significant increase in surrogate markers for adverse clinical events after coronary procedures. Study findings highlight the need for better periprocedural management of these patients and to limit steroid prophylaxis to those with only true ICMH.

Immediate and delayed hypersensitivity after intra-arterial injection of iodinated contrast media: a prospective study in patients with coronary angiography

While hypersensitivity reactions (HSR) to intravenously administered iodinated contrast media (ICM) have been well studied, not much is known about HSR to intra-arterially administered ICM. A prospective observational study was performed to evaluate coronary angiography (CAG)-induced ICM hypersensitivity in patients who underwent CAG using ICM including ioversol, a low-osmolar non-ionic monomer, and iodixanol, an iso-osmolar non-ionic dimer. The HSR were investigated through in-patient monitoring after CAG and telephone interview after discharge. A total of 714 patients were enrolled during the observation period, of whom 26 (3.6%) showed immediate HSR and 108 (15.1%) showed delayed HSR. With regard to severity, proportion of immediate HSR grades 1, 2, and 3 was 57.7%, 38.5%, and 3.8%, respectively, whereas that of delayed HSR grades 1, 2, and 3 was 85.2%, 13.9%, and 0.9%, respectively. Multivariate analysis revealed that previous intra-arterial exposure to ICM was an independent risk factor for immediate HSR (odds ratio (OR) 2.92, 95% confidence interval (CI) 1.22-6.96; p = 0.015). Iodixanol was a significant risk factor for delayed HSR (OR 1.61, 95% CI 1.07-2.43; p = 0.024) and correlated with a higher incidence of delayed HSR within 24-h post-ICM administration compared to ioversol. The incidence rate of immediate and delayed HSR in intra-arterially administered ICM was 3.6% and 15.1%, respectively. Previous exposure to intra-arterially administered contrast media was a significant risk factor for immediate HSR. Compared to ioversol, iodixanol was associated with relatively earlier and more frequent delayed HSR. • In this prospective study, the incidence of immediate and delayed hypersensitivity in intra-arterial injection of contrast media during coronary angiography was 3.6% and 15.1%, respectively. • Delayed hypersensitivity reactions were more common but less severe than immediate hypersensitivity reactions during coronary angiography. • Previous exposure to ICM via intra-arterial route was a significant risk factor for immediate hypersensitivity to intra-arterial contrast medium.

Allergological workup with half‐dose challenge in iodinated contrast media hypersensitivity

Allergological workup with half‐dose challenge in iodinated contrast media hypersensitivity

Hypersensitivity Reactions to Iodinated Contrast Media: Is it a True Allergy?

Classically, hypersensitivity reactions to iodinated contrast media (ICM) have been termed pseudoallergic, allergy-like, or anaphylactoid. The origin of these terms to define ICM hypersensitivity reactions could be in relation to the use of traditional, classic, ionic ICMs. These ionic ICMs have a high osmolality, and the reactions have been considered as secondary to non-specific histamine release. Currently, ionic ICMs have been replaced by non-ionic compounds with low or iso-osmolality, which, although to a lesser extent, can also produce hypersensitivity reactions. In recent years, there has been growing evidence that some of these reactions, especially the more severe, can be triggered by an IgE-dependent mechanism. Also, in recent decades, there has been an increase in non-immediate reactions, especially in the form of maculopapular exanthems occurring up to several days after the administration of ICM. In these non-immediate reactions, the involvement of T lymphocytes has been clearly demonstrated. The finding of positive skin tests and other in vitro studies for ICMs would support a specific immunological mechanism in a percentage of ICM-induced reactions. However, although there is a body of evidence suggesting that ICMs can induce true allergy reactions, the main guidelines for contrast media management, such as those proposed by US (American College of Radiology Manual on Contrast Media) or European (European Society of Urogenital Radiology Guidelines on Contrast Media) societies, continue to consider only immediate reactions and handle them as non-allergic reactions, without any allergy testing. In ICM reactions an allergic evaluation should be mandatory, not only to study the possible mechanisms involved but also to identify the ICM involved in the reaction and to find an alternative one that could be used in future radiological explorations.

Skin Testing for Suspected Iodinated Contrast Media Hypersensitivity

The management of iodinated contrast medium (ICM) hypersensitivity has been a matter of debate. Skin testing to identify a subgroup of ICM allergic patients has been proposed, in addition to complete avoidance, provocation testing, or premedication. The objective of this study was to assess the negative predictive value (NPV) of skin testing for ICM. Patients with a hypersensitivity reaction to ICM who underwent skin testing during a 13.5-year period at a single center were evaluated for re-exposure to a negatively skin-tested ICM. Premedication, consisting of second-generation H1-antihistamines twice a day 48 hours before the examination, was advised only for patients with mast cell disorder or chronic urticaria who had negative skin tests. A total of 597 patients tested for 423 (70.9%) immediate, 118 (19.7%) nonimmediate, and 56 (9.4%) hypersensitivity reactions with undetermined chronology were included. Eighty (13.4%) patients were skin test positive. Re-exposure to ICM occurred in 233 (39.0%) patients and was tolerated in 16 of 17 (94.1%) with at least 1 positive skin test and 201 of 216 (93.1%) with all negative skin tests. Reaction intensity was similar in 4, milder in 10, unknown in 1, and worse in 1 patient although this reaction was deemed to be nonallergic in hindsight. Premedication was administered in 20.7% of patients and associated with more reactions (19.4% vs 5.7%, P= .01). The overall NPV of skin testing for ICM was 93.1% (95% confidence interval [CI] 89.1% to 96.0%), and for immediate and nonimmediate hypersensitivity reactions 94.2% (95% CI 89.6% to 97.2%) and 86.1% (95% CI 72.1% to 94.7%), respectively. We cannot exclude some challenges occurred with a different than the initial culprit ICM, possibly overestimating the NPV. Skin testing for potential ICM hypersensitivity can identify safe alternative(s) for ICM re-exposure especially in patients with an immediate hypersensitivity reaction and/or skin test-proven ICM drug allergy. Reactions on re-exposure were infrequent, mostly milder, and occurred in some patients despite premedication.

The potential utility of iodinated contrast media (ICM) skin testing in patients with ICM hypersensitivity.

Both immediate and delayed hypersensitivity reactions to iodinated contrast media (ICM) are relatively common. However, there are few data to determine the clinical utility of immunologic evaluation of ICM. To evaluate the utility of ICM skin testing in patients with ICM hypersensitivity, 23 patients (17 immediate and 6 delayed reactions) were enrolled from 3 university hospitals in Korea. With 6 commonly used ICM including iopromide, iohexol, ioversol, iomeprol, iopamidol and iodixanol, skin prick (SPT), intradermal (IDT) and patch tests were performed. Of 10 patients with anaphylaxis, 3 (30.0%) and 6 (60.0%) were positive respectively on SPTs and IDTs with the culprit ICM. Three of 6 patients with urticaria showed positive IDTs. In total, 11 (64.7%) had positive on either SPT or IDT. Three of 6 patients with delayed rashes had positive response to patch test and/or delayed IDT. Among 5 patients (3 anaphylaxis, 1 urticaria and 1 delayed rash) taken subsequent radiological examinations, 3 patients administered safe alternatives according to the results of skin testing had no adverse reaction. However, anaphylaxis developed in the other 2 patients administered the culprit ICM again. With 64.7% (11/17) and 50% (3/6) of the sensitivities of corresponding allergic skin tests with culprit ICM for immediate and delayed hypersensitivity reactions, the present study suggests that skin tests is useful for the diagnosis of ICM hypersensitivity and for selecting safe ICM and preventing a recurrence of anaphylaxis caused by the same ICM.

Diagnosis of iodinated contrast media hypersensitivity: results of a 6‐year period

Iodinated contrast media (ICM) hypersensitivity reactions represent a serious problem. Very few clinical data concerning systematic skin testing to ICM are available. To evaluate the utility of ICM skin testing in patients with ICM hypersensitivity. All patients referred over a 6-year period for ICM hypersensitivity past reactions were skin tested for (a) the implicated ICM, or (b) a set of ICM if they were positive for the implicated ICM or if its name was unknown. Forty-four patients, with a median age of 56 years, were studied (15 males, 29 females). The ICM skin tests were positive in 10 patients (23%): one had a positive skin prick test, seven an immediate positive intradermal test (IDT) and two a delayed positive IDT. Skin tests were more often positive in patients with immediate (9/32) as compared with those with non-immediate reactions (1/11). The time interval between the reaction and skin testing was shorter for those patients with an immediate ICM reaction and a positive skin test result (3 months [2.5-174.0]) as compared with those with an immediate ICM reaction and a negative skin test (48 months [6.8-159.0]), (P<0.05). Respiratory allergy was more frequent in the positive group (6/10 vs. 7/34, P<0.05). Skin tests with ICM are positive in a subgroup of patients with ICM hypersensitivity and may play an important role in the diagnosis of ICM allergy.