Anaphylaxis Following Contrast-Enhanced CT with Iodixanol: A Case Report and Literature Review.

Background: Iodixanol-induced anaphylactic reaction is a well-known adverse event of contrast agents, which are generally well-tolerated and reversible. Serious and fatal reactions such as anaphylactic shock after computed tomography (CT) enhancement have been described. However, there is no data on these events in the literature. Objective: This report describes a case of a serious anaphylactic reaction, possibly related to iodixanol and provides an overview of case reports. Case Summary: A 47-year-old women who experienced persistent abdominal pain for more than one month, was proposed of hiatal hernia with CT images taken two weeks previously and was admitted to the gastrointestinal surgery department. The patient underwent contrast-enhanced abdominal CT for the evaluation of multiple intraperitoneal hemodynamic features. A few minutes after abdominal enhanced CT scan, the patient was pale, sweating, had muscle tension and trembling, even coma and profound hypotension with 90/43 mm Hg. Immediately she was supported with oxygen inhalation, was treated with adrenaline subcutaneously, dexamethasone intravenously, and rapid intravenous drip of compound sodium chloride. Ten minutes later, the patient was in respiratory and cardiac arrest and the pupils were dilated. CPR and intermittant static push of 1 mg adrenaline were immediately carried. After endotracheal intubation, the patient's spontaneous heart rate and pupils recovered, and her blood pressure recovered to 105/53 mm Hg. It was suggested that the patient was suffering from iodixanol-induced anaphylactic shock and nephropathy, and she was transferred to the intensive care unit. Despite immediate treatment, the patient died. Conclusion: A 47-year-old female patient with no history of allergies developed severe fatal anaphylactic shock after receiving iodixanol. Although contrast agents induced anaphylactoid/anaphylactic reactions do not often occur, clinicians should be conscious of the potentially serious anaphylactic reaction, which could lead to a life-threatening or fatal event.

Hypersensitivity reactions to iodinated radiocontrast media: Cluster analysis reveals distinct clinical phenotypes.

Background: Drug hypersensitivity reaction (DHR) to iodinated radiocontrast media (iRCM) is reported in 1%-3% of injections. Risk assessment of patients with suspicion of DHR to iRCM relies solely on clinical phenotyping and drug allergy workup. Using a novel unsupervised TwoStep cluster analysis, we aimed to identify prototypic patterns within a large cohort of patients evaluated for a potential iRCM DHR. Methods: A retrospective study was conducted using data from the Drug Allergy and Hypersensitivity Database of the Allergy Unit, University Hospital of Montpellier, Montpellier, France. All referred patients during February 2001 to December 2019 with suspicion of iRCM DHR with either confirmed positive or confirmed negative skin tests were included in the analysis. Results: A total of 1439 patients were evaluated. The chronology of the index reaction was immediate and nonimmediate in 77.1% and 22.4%, respectively. Cluster analysis categorized the total study population in 5 clusters. Cluster 1 compiled all nonimmediate and cluster 2-5 almost all immediate reactors. Cluster 1 and 2 had recent reactions (<1 y) with mostly known iRCMs and the highest iRCM allergy prevalence (16-17%). In the other clusters, more remote reactions, unknown iRCMs and a lower allergy prevalence (3-8%) was observed. Chronology and semiology of the index reaction were the factors most strongly differentiated among clusters. History of anaphylactic shock and chronology of immediate hypersensitivity reactions were shown to be independent predictors of allergy with adjusted OR (aOR) of 4.68 (95%CI: 3.01-7.27, p < 0.001) and 2.51 (95%CI: 1.67-3.78, p < 0.001), respectively. Conclusions: Unsupervised cluster analysis identified 5 prototypic patterns within patients with a suspected DHR to iRCMs. Well-phenotyped patients cluster together in 2 groups in which the prevalence of allergy is approximately 1 in 6. However, this value decreases for patients with reactions dating back to more than a decade.

Evaluating pharmacists' knowledge, attitude, and practices toward amiodarone cross-reactivity with iodine: a cross-sectional pilot study.

Introduction: Iodine is a vital mineral of the human body that acts by maintaining the health of the thyroid gland. Research has shown that iodine-rich food allergy (i.e., seafood allergy) is not caused by iodine itself; instead, it is caused by other proteins including tropomyosin and parvalbumin in shellfish and fish, respectively. Amiodarone is a commonly used antiarrhythmic agent containing a significant amount of iodine. Objective: This study's objective was to assess pharmacists' knowledge, attitude, and practices toward the misconception of iodine allergy and the cross-reactivity with amiodarone. Methods: In February 2020, a cross-sectional study was conducted by sending out an online survey to three pharmaceutical organizations (Saudi Pharmaceutical Society, Kuwait Pharmaceutical Association, and Oman Pharmaceutical Society). Additionally, an electronic questionnaire was administered to pharmacists attending the Dubai International Pharmaceuticals and Technologies Conference and Exhibition 2020 (DUPHAT). Chi-square or Fisher's exact test, when appropriate, were used to compare categorical variables. The statistical analyses were carried out using SPSS software. Results: Data were collected from 66 respondents. However, only 61 (92.4%) were included in the final analysis following the exclusion of incomplete responses. The mean age of participants was 35 ± 8.48 years. The majority of participants did not have the Board of Pharmacy Specialties Certification (54.1%). Moreover, (41%) of participants licensed as pharmacists with more than 10 years of initial pharmacy licensure. Forty-three (70.5%) of participants had the misconception that iodine allergy should be considered before amiodarone administration, 20/32 (62.5%) of whom considered iodine allergy alone thought that premedication with corticosteroids and/or antihistamines is necessary. Concerning iodine allergy and amiodarone use, there was no significant difference in knowledge between the pharmacists who have board certification and those who did not. Conclusion: Pharmacists' misconception concerning iodine allergy and cross-reactivity with amiodarone was evident. Implementation of educational programs targeting pharmacists is necessary to correct these misconceptions.

Allergy to Radiocontrast Dye.

Radiocontrast media (RCM) are common elicitors of immediate and nonimmediate hypersensitivity reactions, manifesting predominantly as urticaria/anaphylaxis or exanthems, respectively. In the minority of patients with immediate hypersensitivity reactions to RCM allergy is demonstrated by positive skin tests. However, data show that assessment by an allergist/immunologist is beneficial for managing patients with previous immediate and nonimmediate hypersensitivity reactions. For future RCM-enhanced examinations in patients with previous reactions, structurally different, skin test-negative preparations should be applied. The efficacy of this strategy is confirmed by drug provocation tests or exposures confirming or excluding RCM hypersensitivity and demonstrating tolerability of alternative RCM.

Radiocontrast Media Hypersensitivity Reactions in Children.

Hypersensitivity reactions to radiocontrast media seem to be rare in children. Furthermore, the use of radiocontrast media in children remains quite safe in terms of the severity of reactions. Since pediatric guidelines are lacking, the diagnostic workup employed in adults could be adapted to children, taking into account that results have not yet been validated in this age group. Specific protocols for risk stratification and management of severe reactions have been proposed so far.

Successful Desensitization to the Radiocontrast Material Iohexol (Omnipaque™).

Adverse reactions to radiocontrast media (RCM) are rare and occur predominantly in association with intravenous administration but may also occur with intra-arterial and nonvascular injections (e.g., retrograde pyelography, intra-articular injections) of RCM. This article reports the case of a 52-year-old lady who was known to have amyloidosis secondary to rheumatoid arthritis and was on regular renal replacement therapy. She was under follow-up for regular angioplasties to manage the central vein stenosis that was affecting her right brachiocephalic arteriovenous fistula (AVF) and was referred to our Immunology service when she developed an allergic reaction after her AVF angioplasty (central venoplasty). Despite being dialysed immediately post-angioplasty, she complained of skin rash and itching with hoarseness of voice that developed almost six to eight hours post-angioplasty. We decided to arrange the iodinated non-ionic iso-osmolar contrast agent iodixanol (Visipaque™) for her instead, as it is known to be better tolerated in patients with reactions to Omnipaque™ due to its lower osmolarity as compared to Omnipaque™. However, since it was the first time to request this contrast in our hospital, it was not possible due to logistical reasons. It was necessary that our patient continued to undergo angioplasty every three months, however, she was developing more severe and earlier symptoms with each subsequent exposure to the radiocontrast medium. After her latest reaction of generalized itching and angioedema with shortness of breath during the procedure despite premedication, it was decided for her to undergo desensitization to Omnipaque™. In the absence of a published protocol for this, we used a protocol used for desensitization to Visipaque™. She showed an excellent response and completed her remaining angioplasties until Visipaque™ became available. Hence, desensitization to Omnipaque™ using the published protocol to Visipaque™ is likely to help patients allergic to Omnipaque™ or where Visipaque™ is not available or non-affordable in low/middle-income countries.

Clinical implication of detecting sensitization to iodinated radiocontrast media in the basophil activation test by flow cytometry.

The use of iodinated radiocontrast media is necessary for visualization. A number of patients have adverse effects of various nature and severity when these drugs are administered. Routine allergy tests do not provide adequate diagnosis of reactions to drugs in this group. The aim of this work is to assess the capabilities of the basophil activation test to confirm sensitization to non-ionic iodinated radiocontrast media, as well as to select a safe alternative drug in patients with a burdened history. Basophil activation test by flow cytometry was performed in 184 patients The Nikiforov Russian Centre of Emergency and Radiation Medicine¼ EMERCOM of Russia and 32 volunteers using ultravist, omnipack, and optiray. The presence of sensitization was assessed based on the basophil activation index, as well as spontaneous and anti-IgE antibody-induced activation of basophils and the population of T-lymphocytes type 2 immune response. The volunteers showed no sensitization to iodinated radiocontrast media. In patients with a medium degree of hypersensitivity reaction in vivo, in vitro sensitization to drugs was detected 4 times more often than in patients with a mild degree (51% versus 13.5%). In patients with systemic reactions to the administration of a known drug, in vitro sensitization was confirmed in 86% of cases, while the frequency of detection of sensitization to drugs did not differ. Spontaneous activation of basophils in patients and type 2 T-lymphocytes were 2 times higher than in volunteers. Patients were more likely to have low (less than 30%) activation of basophils for anti-IgE antibodies. The specificity of the basophil activation test with iodinated radiocontrast media was 100% with a sensitivity of 94.1%. Most patients were able to select a non-sensitizing contrast. Inclusion in the algorithm of spontaneous and anti-IgE antibody-induced activation of basophils and a population of T-lymphocytes type 2 immune response will allow the doctor to carry out a personalized approach to the management of patients with a burdened history.

The conundrum of contrast-induced acute kidney injury.

More than sixty years have elapsed since contrast induced nephropathy (CIN) was first described in the medical literature. This term has since been extensively explored, with a variety of studies conducted to investigate its incidence and various mechanisms examined to explain its pathophysiology. However, the topic of CIN remains one of controversy with a widely variable and often questionable incidence derived from various studies. The past two decades have seen a surge in reports questioning the existing of CIN altogether and if more harm is actually being caused to patients out of fear of this potential complication. We have attempted to review relevant studies regarding CIN and highlight the key points of its surmised understanding. The review has a higher focus on more recent literature and updates, in order to determine if an accurate estimate can be made on the incidence of CIN. While there was certainly no lack of material available, practically all the studies reviewed were limited by one or more significant drawbacks that limited the reliability of their conclusions regarding CIN. Based on the information reviewed, the strengths and the flaws encountered in other studies can be used to design a randomized control trial that may help in concluding the longstanding debate on this topic. However due to time, financial, and perhaps even ethical constraints such a trial will be difficult to arrange, and so a definitive answer on CI-AKI, and whether it really exist, may continue to elude clinicians.

Anaphylaxis-a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis.

Anaphylaxis is an acute, potential life-threatening systemic allergic reaction that may have a wide range of clinical manifestations. Severe anaphylaxis and/or the need for repeated doses of epinephrine to treat anaphylaxis are risk factors for biphasic anaphylaxis. Antihistamines and/or glucocorticoids are not reliable interventions to prevent biphasic anaphylaxis, although evidence supports a role for antihistamine and/or glucocorticoid premedication in specific chemotherapy protocols and rush aeroallergen immunotherapy. Evidence is lacking to support the role of antihistamines and/or glucocorticoid routine premedication in patients receiving low- or iso-osmolar contrast material to prevent recurrent radiocontrast media anaphylaxis. Epinephrine is the first-line pharmacotherapy for uniphasic and/or biphasic anaphylaxis. After diagnosis and treatment of anaphylaxis, all patients should be kept under observation until symptoms have fully resolved. All patients with anaphylaxis should receive education on anaphylaxis and risk of recurrence, trigger avoidance, self-injectable epinephrine education, referral to an allergist, and be educated about thresholds for further care.

CHA2DS2-VASc score as a novel predictor for contrast-induced nephropathy after percutaneous coronary intervention in acute coronary syndrome.

BACKGROUND: CHA2DS2-VASc score, used for atrial fibrillation to assess the risk of embolic complications, have shown to predict adverse clinical outcomes in acute coronary syndrome (ACS), irrespective of atrial fibrillation. This study envisaged to assess the predictive role of CHA2DS2-VASc score for contrast-induced nephropathy (CIN) in patients with ACS undergoing percutaneous coronary intervention (PCI). METHODS: A total of 300 consecutive patients with ACS undergoing PCI were enrolled in this study. CHA2DS2-VASc score was calculated for each patient. These patients were divided into two groups as Group 1 (with CIN) and Group 2 (without CIN). CIN was defined as increase in serum creatinine level ≥0.5 mg/dL or ≥25% increase from baseline within 48 h after PCI. After receiver operating characteristic curve analysis, the study population was again classified into two groups: CHA2DS2-VASc score ≤3 group (Group A) and score ≥4 group (Group B). RESULTS: CIN was reported in 41 patients (13.6%). Patients with CIN had a higher frequency of hypertension, diabetes mellitus, and had a lower left ventricular ejection fraction and baseline estimated glomerular filtration rate. Receiver operating characteristic curve analysis showed good predictive value of CHA2DS2-VASc score for CIN (area under the curve 0.81, 95% CI 0.73-0.90). Patients with a CHA2DS2-VASc score of ≥4 had a higher frequency of CIN as compared with patients with score ≤3 (56.8% vs 4.8%; p = 0.0001) with multivariate analysis demonstrating CHA2DS2-VASc score of ≥4 to be an independent predictor of CIN. CONCLUSION: In patients with ACS undergoing PCI, CHA2DS2-VASc score can be used as a novel, simple, and a sensitive diagnostic tool for the prediction of CIN.

Intradermal Testing With Radiocontrast Media to Prevent Recurrent Adverse Reactions.

OBJECTIVE. Adverse drug reactions (ADRs) to radiocontrast media are a significant social and economic burden and are difficult to predict. Because some ADRs to radiocontrast media may be immunologically induced, a skin test with diluted 1:10 radiocontrast media has been used to predict ADRs. However, using this test in clinical practice is difficult because of its low sensitivity. SUBJECTS AND METHODS. This study enrolled 36 patients with a history of immediate ADR to radiocontrast media who visited the Allergy and Asthma Clinic of Severance Hospital from 2017 to 2018. Patients underwent intradermal testing (IDT) with five types of diluted (1:10) and undiluted radiocontrast media (iohexol, iobitridol, iopamidol, iopromide, and iodixanol). The IDT result was regarded as positive if at least one radiocontrast medium elicited a positive reaction. Positivity of IDT and sensitivity to the culprit radiocontrast medium were calculated and compared. For subsequent CT examinations with a radiocontrast medium, the contrast agent eliciting a negative skin reaction in IDT was selected, excluding the previous culprit radiocontrast medium. RESULTS. IDT positivity and sensitivity for the culprit radiocontrast medium at 1:10 dilution were 47.2% and 47.2%, respectively, whereas the positivity and sensitivity for the undiluted radiocontrast medium were 86.1% and 75.0%, respectively. The positivity and sensitivity were higher with frequent radiocontrast medium use or with severe reaction. Of 22 patients who underwent another CT examination with the contrast medium selected on the basis of IDT results, 21 (95.5%) did not experience an ADR. CONCLUSION. IDT to prevent ADR should be performed with undiluted radiocontrast medium. Selecting an alternative radiocontrast agent on the basis of IDT results can be clinically useful to prevent recurrent ADRs to radiocontrast media.

Is it possible to prevent contrast-induced nephropathy with dexpanthenol?

PURPOSE: Contrast-induced nephropathy (CIN) is one of the side effects of diagnostic procedures. Oxidative stress plays an important role in CIN's pathophysiology. Dexpanthenol (Dexp) is a substance with antioxidant efficacy. We investigated the likely protective effects of dexpanthenol for CIN. METHODS: Twenty-four Sprague-Dawley rats were divided randomly into four groups of 6 rats; control (group 1), Dexp (group 2), CIN (group 3) and Dexp + CIN (group 4). All rats were restricted of water moderately to facilitate of nephrotoxicity. Dexp was administered into the intraperitoneally at a dose of 500 mg/kg for 5 days in groups 2 and 4. The same amount of saline was applied via intraperitoneally to group 1 and 3. In CIN and Dexp + CIN groups, L-NAME (10 mg/kg), tenoxicam (0.5 mg/kg) and sodium amidotrizoate (10 ml/kg) were administered on the 4th day via the tail vein for CIN. All rats were euthanized on the 6th day and samples for biochemical and pathological evaluations were collected. RESULTS: When the Dexp + CIN group and the CIN group were compared, it was found to be provide a significant decline at the level of acute tubular injury and necrosis in kidney biopsies by dexp. Furthermore Dexp significantly reduced the serum cystatin C (Cys-C) levels, not serum creatinine. There was no statistically significant difference between the groups in total oxidant and antioxidant levels. CONCLUSIONS: Dexpanthenol did not have significant effect on oxidative stress of acute kidney injury on this rat model. However, it has ameliorated serum Cys-C levels and histopathological findings of CIN.

Radiocontrast Media Hypersensitivity: Skin Testing Differentiates Allergy From Nonallergic Reactions and Identifies a Safe Alternative as Proven by Intravenous Provocation.

BACKGROUND: Hypersensitivity reactions occurring within minutes after intravascular injection of iodinated radiocontrast media (RCM) are not rare and have been previously considered to be nonallergic. However, in the last decades, evidence is increasing that genuine RCM allergy may present as either full-blown anaphylaxis or delayed exanthematous skin reaction. OBJECTIVES: We aimed to assess whether allergy diagnostics including skin and provocation testing can differentiate between nonallergic and allergic RCM hypersensitivity by identifying the causative RCM as well as tolerated alternative RCM. METHODS: We retrospectively evaluated clinical and diagnostic data from 45 consecutive patients with RCM hypersensitivity. RESULTS: Immediate nonallergic RCM hypersensitivity was diagnosed in 21 patients, immediate-type RCM allergy in 11, delayed-type RCM allergy in 11, and delayed-type iodine allergy in 2. All patients with immediate-type RCM allergy had a history of moderate to severe anaphylaxis. Eleven of 13 patients with delayed-type allergic reactions including the 2 cases of iodine allergy suffered from maculopapular exanthem developing several hours to days after exposure, 1 was a systemic hypersensitivity syndrome, and 1 a fixed drug eruption. Of 18 RCM-allergic patients tested, all tolerated an alternative RCM in the intravenous provocation. CONCLUSIONS: The diagnostic sensitivity of intradermal RCM testing to identify allergic patients is high in both immediate-type and delayed-type RCM allergy. Intravenous provocation with a skin test-negative RCM is safe and enables identification of a tolerated alternative RCM. Additional skin testing of iodine solution is required to identify patients with iodine allergy.

Adverse Drug Reactions to Radiographic Contrast Media in a Teaching Hospital in North India: An Observational Study.

BACKGROUND: Radiocontrast media are used extensively nowadays to visualize internal organs. Currently, non-ionic iodinated contrast media are used which are generally considered to be safe but some adverse reactions have been reported. Thus, the present study was carried out to analyze the nature and incidence of adverse drug reactions (ADRs) to radiographic contrast media in a teaching hospital. METHODS: An observational study carried out for a period of six months in a teaching hospital. Contrast media induced adverse reactions were analyzed in terms of affected organs, rate, causality assessment, severity and preventability. The treatment and outcomes of adverse events were also recorded. Naranjo Probability Scale was used to evaluate the relationship between the contrast agent used and the suspected ADR. The severity of the suspected ADRs was determined using Hartwig Scale and preventability was assessed using modified Schumock and Thornton criterion. RESULTS: A total of 15 suspected ADRs occurred in 11 patients with an incidence of 1.4%. It included 5 (45.4%) males and 6 (54.5%) females (p < 05). The highest percentage (72.7 %) of ADRs was seen in adult patients, the mean age being 40.8 years. Vomiting (33.3%) was the most common ADR noted followed by severe nausea and rashes. 64.7 % of ADRs were categorized as probable and 35.3 % were possible. Adverse reactions required treatment in 46.6% patients. There was no fatality reported. CONCLUSION: The reactions observed were mild to moderate in severity and occurred within 30 minutes of the administration of the contrast.

Adverse reactions to drugs and biologics in patients with clonal mast cell disorders: A Work Group Report of the Mast Cells Disorder Committee, American Academy of Allergy, Asthma & Immunology.

Providers caring for patients with mastocytosis are tasked with the decision to consider therapeutic options. This can come with some trepidation because information available in the public domain lists numerous mast cell (MC) activators based on data that do not discriminate between primates, rodents, and MC lines; do not consider dosage; and do not take into account previous exposure and resultant clinical findings. This being said, there is support in the literature for an enhanced MC response in some patients with mastocytosis and in cases in which there is a greater incidence of adverse reactions associated with certain antigens, such as venoms and drugs. Thus this report provides a comprehensive guide for those providers who must decide on therapeutic options in the management of patients with clonal MC disease.

Acute pulmonary edema induced by non-ionic low-osmolar radiographic contrast media.

BACKGROUND: Non-cardiogenic pulmonary edema (NCPE) after intravenous (iv) administration of non-ionic radiocontrast media (RCM) is a rare but life-threatening complication. In a context of emergency, its diagnosis is difficult. CASE REPORT: We report the case of a 55-year-old woman who developed an acute pulmonary edema following iv infusion of non-ionic, low-osmolar RCM during abdominal CT scan. She needed a 24-hour hospitalization in intensive care unit for an acute hypoxemic dyspnea. She was falsely treated at first for an anaphylactic reaction, and then for a cardiac failure. She improved with cortisone and diuretic treatment. CONCLUSION: Although NCPE has been rarely reported after RCM injection, it remains an acute severe complication that has to be considered. The differential diagnosis involves multiple pathogenic patterns giving furthermore complexity in choosing an appropriate treatment.

Electronic Consultation Support System for Radiocontrast Media Hypersensitivity Changes Clinicians' Behavior.

PURPOSE: Patients with a history of radiocontrast media (RCM) hypersensitivity can be overlooked, resulting in repeated reactions. Therefore, a consultation support system for RCM hypersensitivity has been in operation at Seoul National University Bundang Hospital since December 2011. We analyzed the effect of this system on physicians' practice. METHODS: A retrospective study was conducted on patients with previous RCM reactions (December 1, 2010 to November 30, 2012). The control period was December 2010 to November 2011, and the intervention period was December 2011 to November 2012. The primary outcome was the composite outcome of premedication and consultation. Premedication was defined as preventive medication prescribed by the physician who ordered RCM-enhanced computed tomography (CT) at the same time. The secondary outcome was the recurrence rate after using the consultation support system. RESULTS: A total of 189 clinicians prescribed 913 CT scans during the control period and 225 clinicians performed 1,153 examinations during the intervention period. The odds ratio (OR) of achieving the composite outcome increased significantly after use of the consultation support system (OR, 1.54; 95% confidence interval [CI], 1.15-2.05). Clinicians in both medical (OR, 1.48; 95% CI, 1.06-2.07) and surgical (OR, 2.07; 95% CI, 1.24-3.46) departments showed significant changes in their behavior, whereas those in the emergency department did not (OR, 1.07; 95% CI, 0.41-2.78). Professors (OR, 1.47; 95% CI, 1.06-2.04) and trainees (OR, 1.97, 95% CI, 1.22-3.18) showed significant changes in their behavior toward patients with previous RCM reactions. The behavior of 86 clinicians who ordered CT scans during both the control and intervention periods was unchanged. CONCLUSIONS: The consultation support system for those with previous RCM hypersensitivity reactions changed physicians' practice patterns and decreased recurrent RCM hypersensitivity reactions as well.

Successful Graded Dose Challenge to Iodixanol Radiocontrast Media in a Patient With Delayed Anaphylaxis to Iohexol.

We present a case of an 82-year-old male with known radiocontrast media (RCM) hypersensitivity who was admitted to our hospital with gangrene of his right toe. The plan for revascularization of his lower extremity required an angiogram. This presented a management challenge as the patient had experienced 2 episodes of delayed anaphylaxis to Omnipaque (iohexol) RCM, and based on a literature review, there was no known or established precedent on a safe procedure in these situations. The patient was premedicated and given a graded dose challenge of an alternative RCM (iodixanol) prior to the radiographic study. He was given 1% of the total expected dose 1 hour before to the procedure and an additional 10% for the 30 minutes prior. He was then given the final dose in the operating room. Following angiogram, the patient was monitored for 18 hours in the postanesthesia care unit, with no adverse reactions. He was placed on a prednisone taper for 1 week, with daily diphenhydramine. The patient remained asymptomatic throughout the hospital course. This novel approach to RCM hypersensitivity management lends itself to a hope that graded dose challenges may play a greater role in the management of these patients.