Management of hypersensitivity reactions to iodinated contrast media

International Consensus on drug allergy

When drug reactions resembling allergy occur, they are called drug hypersensitivity reactions (DHRs) before showing the evidence of either drug-specific antibodies or T cells. DHRs may be allergic or nonallergic in nature, with drug allergies being immunologically mediated DHRs. These reactions are typically unpredictable. They can be life-threatening, may require or prolong hospitalization, and may necessitate changes in subsequent therapy. Both underdiagnosis (due to under-reporting) and overdiagnosis (due to an overuse of the term ‘allergy’) are common. A definitive diagnosis of such reactions is required in order to institute adequate treatment options and proper preventive measures. Misclassification based solely on the DHR history without further testing may affect treatment options, result in adverse consequences, and lead to the use of more-expensive or less-effective drugs, in contrast to patients who had undergone a complete drug allergy workup. Several guidelines and/or consensus documents on general or specific drug class-induced DHRs are available to support the medical decision process. The use of standardized systematic approaches for the diagnosis and management of DHRs carries the potential to improve outcomes and should thus be disseminated and implemented. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), formed by the European Academy of Allergy and Clinical Immunology (EAACI), the American Academy of Allergy, Asthma and Immunology (AAAAI), the American College of Allergy, Asthma and Immunology (ACAAI), and the World Allergy Organization (WAO), has decided to issue an International CONsensus (ICON) on drug allergy. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences and deficiencies of evidence, thus providing a comprehensive reference document for the diagnosis and management of DHRs.

Diagnosis of immediate hypersensitivity reactions to radiocontrast media

BACKGROUND

No consensus exists on the diagnostic approach for immediate hypersensitivity reactions (IHR) to radiocontrast media (RCM). We analyzed the diagnostic value of a skin test (ST), drug provocation test (DPT) and basophil activation test (BAT) in patients with symptoms compatible with IHR to RCM.

METHODS

Ninety patients with symptoms suggestive of IHR to RCM were evaluated. ST with a panel of RCM was performed, and if negative, DPT was carried out with the culprit RCM. If ST or DPT were positive, tolerance was assessed with an alternative RCM and BAT was carried out with the same panel used for ST.

RESULTS

Eight (8.9%) cases were confirmed as having IHR, 5 (62.5%) by ST and 3 (37.5%) by DPT. Five from those confirmed as IHR (62.5%) had a positive BAT.

CONCLUSIONS

Hypersensitivity to RCM was confirmed in 9%, by ST or DPT. BAT proved a valuable method for diagnosis.

A delayed, unusual non-cardiogenic pulmonary edema after intravascular administration of non-ionic, low osmolar radiocontrast media for coronary angiography

Non-cardiogenic pulmonary edema (NCPE) is a rare adverse reaction to iodinated radiocontrast media (RCM), in which all previous cases were immediate reactions. A 56-year-old male was given iopamidol, a non-ionic, low osmolar RCM, during coronary artery angiography. He developed pulmonary edema and fever a day after the procedure. Despite diuretic therapy, the patient's pulmonary edema worsened and his high fever persisted. The patient's pulmonary edema was eventually resolved with intravenous steroid treatment. We interpreted the patient's condition as NCPE manifesting as a delayed reaction to RCM. To our knowledge, our case is the first to show NCPE as a delayed hypersensitivity reaction.

Severe drug-induced anaphylaxis: analysis of 333 cases recorded by the Allergy Vigilance Network from 2002 to 2010

BACKGROUND

A few series of well-documented cases of severe drug-induced anaphylaxis (SDA) are available.

METHODS

Cases collected by the Allergy Vigilance Network from 2002 to 2010 were analyzed for clinical signs, causative drugs, and efficacy of a stepwise approach to diagnosis, using skin tests, laboratory tests, and oral challenges.

RESULTS

Three hundred and thirty-three cases concerned 300 adults (90.1%) and 33 children (9.9%): 206 females (61.9%) and 127 males (38.1%). Mean age was 42.7 ± 18 years. Anaphylactic shock (76.6%), severe systemic reactions (10.5%), acute laryngeal edema (9%), severe bronchospasm (2.1%), and six fatal cases (1.8%) were recorded. There were 270 cases (81.1%) of ambulatory anaphylaxis. Sixty-three cases (18.9%) occurred during anesthesia. Hospitalization was required in 94.8% of cases. 23.7% of patients were admitted to an intensive care unit. Epinephrine was used in 57.9% of cases. Eighty-four drugs were incriminated: antibiotics (49.6%), muscle relaxants, latex and anesthetics (15%), nonsteroidal anti-inflammatory drugs (10.2%), acetaminophen (3.9%), iodinated or magnetic resonance imaging contrast media (4.2%), immunotherapy and vaccines (3.9%), and other drugs (13%). Among antibiotics, amoxicillin (97 cases), other penicillins (four cases), cephalosporins (41 cases), quinolones (15 cases), and pristinamycin (seven cases) were the most common. The diagnosis of drug hypersensitivity was obtained by skin tests in 72.9%, laboratory tests only in 2.4% of cases, and oral challenges (OCs) only in 3.9% of cases.

CONCLUSIONS

Three hundred and thirty-three case reports provided data on drugs involved in severe anaphylaxis. The efficacy of skin tests and poor use of laboratory tests are underlined. Further progress may depend on OCs.

The Effectiveness of Automatic Recommending System for Premedication in Reducing Recurrent Radiocontrast Media Hypersensitivity Reactions

BACKGROUND

Non-ionic radiocontrast media (RCM) is rarely associated with hypersensitivity reactions. Premedication of patients who reacted previously to RCM with systemic corticosteroids and/or antihistamines can help reduce recurrent hypersensitivity reactions. However, premedication is still not prescribed in many cases for various reasons. This study aimed to determine the effectiveness of our novel RCM hypersensitivity surveillance and automatic recommending system for premedication.

METHODS AND RESULTS

Hospitalized patients with a history of RCM hypersensitivity were identified in an electronic medical record system that included a mandatory reporting system for past adverse drug reactions. In 2009, a novel automatic prescription system was added that classified index RCM reactions by severity and dispensed appropriate corticosteroid and/or antihistamine pretreatment prior to new RCM exposures. The data from 12 months under the previous system and 12 months under the current system were compared. The two systems had similar overall premedication rates (91% and 95%) but the current system was associated with a significantly higher corticosteroid premedication rate (65% vs. 14%), which significantly reduced the breakthrough reaction rate (6.7% vs. 15.2%). The current system was also associated with increased corticosteroid and antihistamine premedication of patients with a mild index reaction (61% vs. 7%) and a reduction in their breakthrough reaction rate (6% vs. 15%).

CONCLUSIONS

Premedication with corticosteroid and/or antihistamine, which was increased by our novel automatic prescription system, significantly reduced breakthrough reactions in patients with a history of RCM hypersensitivity.

Skin test concentrations for systemically administered drugs -- an ENDA/EAACI Drug Allergy Interest Group position paper

Skin tests are of paramount importance for the evaluation of drug hypersensitivity reactions. Drug skin tests are often not carried out because of lack of concise information on specific test concentrations. The diagnosis of drug allergy is often based on history alone, which is an unreliable indicator of true hypersensitivity.To promote and standardize reproducible skin testing with safe and nonirritant drug concentrations in the clinical practice, the European Network and European Academy of Allergy and Clinical Immunology (EAACI) Interest Group on Drug Allergy has performed a literature search on skin test drug concentration in MEDLINE and EMBASE, reviewed and evaluated the literature in five languages using the GRADE system for quality of evidence and strength of recommendation. Where the literature is poor, we have taken into consideration the collective experience of the group.We recommend drug concentration for skin testing aiming to achieve a specificity of at least 95%. It has been possible to recommend specific drug concentration for betalactam antibiotics, perioperative drugs, heparins, platinum salts and radiocontrast media. For many other drugs, there is insufficient evidence to recommend appropriate drug concentration. There is urgent need for multicentre studies designed to establish and validate drug skin test concentration using standard protocols. For most drugs, sensitivity of skin testing is higher in immediate hypersensitivity compared to nonimmediate hypersensitivity.

Clinical value of radiocontrast media skin tests as a prescreening and diagnostic tool in hypersensitivity reactions

BACKGROUND

Some radiocontrast media (RCM) hypersensitivity reactions may have underlying IgE- or T-cell-mediated mechanisms. RCM skin testing may be useful for predicting future reactions.

OBJECTIVE

To investigate the clinical value of RCM skin testing before computed tomography and after RCM hypersensitivity reactions.

METHODS

Patients who underwent RCM skin testing were a prospective sample of convenience at a single medical center and were tested just before their pending nonionic RCM-enhanced computed tomogram. In addition, skin test data of patients who were referred to the allergy clinic because of their previous RCM hypersensitivity reactions were reviewed retrospectively.

RESULTS

A total of 1048 patients enrolled in the study prospectively. Of these, 672 (64.1%) had never been exposed to RCM. Of the 376 previously exposed to RCM, 61 (16.2%) had a history of at least one mild RCM-associated reaction, 56 (91.8%) had immediate reactions, and 5 had no-immediate reactions. There was only 1 positive immediate hypersensitivity RCM skin test result (0.09%). There were 51 mild immediate reactions (4.9%), 1 moderate immediate reaction (0.09%), 8 mild nonimmediate reactions (0.76%), and 1 moderate nonimmediate reaction (0.09%). There was only 1 positive delayed hypersensitivity skin test result (0.09%), retrospectively determined, in 1 (11.1%) of the nonimmediate RCM-associated reactions. Sensitivity of RCM skin testing was significantly higher with severe immediate reactions (57.1%) than mild reactions (12.9%) and moderate reactions (25.0%) in the retrospective review of diagnostic skin test data (P = .03).

CONCLUSION

RCM skin testing for screening is of no clinical utility in predicting hypersensitivity reactions. RCM skin testing may have modest utility in retrospectively evaluating severe adverse reactions.

Immediate hypersensitivity reactions to IV non-ionic iodinated contrast in computed tomography

BACKGROUND

With use of computed tomography (CT), intravenous contrast media is used routinely to help define anatomy and identify any pathology. Non-ionic iodinated contrast agents have largely replaced ionic agents and although rare, reactions to contrast are still important and more so with the continual increase in CT examinations in the last decade.

OBJECTIVE

To examine the incidence, severity and risk factors of immediate hypersensitivity reactions to intravenous non-ionic iodinated contrast in CT.

METHODS

Data of consecutive patients in an Australian tertiary hospital who developed immediate hypersensitivity reactions to intravenous iopromide during CT were collected and compared with the results of all contrast CTs performed over a four year period. Chi-square statistics and odds ratio are calculated on the variables of age, gender, referral source and seasons of the study.

RESULTS

Forty-seven patients had immediate hypersensitivity reactions of 29,962 patients who underwent contrast CT (0.16%). Thirty-three patients (70%) had a mild reaction, 11 (23%) moderate and three (7%) severe. Sixteen (34%) were male and 31 (66%) were female. Sixty-eight percent were under 55-years of age. Reactions occurred in 0.35% (34 patients) of all outpatients, 0.07% (6 patients) of all emergency patients, and 0.06% (7 patients) of all in-patients. Eighteen (38%) occurred in spring, seven (15%) in summer, 17 (36%) in autumn and five (11%) in winter. There is a statistically significant higher risk of contrast reactions in females (Odds Ratio [OR] 2.41 p = 0.005), patients younger than 55-years old (OR 2.46, p = 0.005), outpatients (OR 5.42, p < 0.001) and CTs performed in spring and autumn (OR 2.77, p = 0.002).

CONCLUSION

The incidence of immediate hypersensitivity reactions in contrast CT is low and mostly mild. Risk factors include female, younger than 55-years of age, outpatients and CT examinations performed in spring and autumn. This is the first study to observe such a seasonal variation.

Definitions and mechanisms of drug hypersensitivity

Adverse drug reactions are a difficult problem faced by clinicians in everyday practice. The mechanisms of drug hypersensitivity are not well understood. This is reflected by difficulties in their classification, which is mainly based upon the current knowledge of immunologic and nonimmunologic mechanisms, onset of symptoms (immediate or nonimmediate) and morphology. For the individual patient, the correct diagnosis and classification is important because strict avoidance of the offending drug might be of vital importance. Considerable experience is required to guide management, to interpret results of investigations and to undertake drug challenges. This article summarizes the current knowledge regarding definitions and mechanisms. However, the field of drug hypersensitivity is rapidly expanding. Modern drugs such as biological agents bare hypersensitivity risks that are potentially mediated by, so far, unknown mechanisms.

Nonallergic drug hypersensitivity reactions

BACKGROUND

Nonallergic drug hypersensitivities, also referred to as pseudoallergic or anaphylactoid reactions, have clinical manifestations that are often indistinguishable from allergic reactions.

METHODS

We performed a PubMed search using the terms 'drug allergy, drug hypersensitivity, pseudoallergies, anaphylaxis and nonallergic drug reactions' and reviewed 511 publications dated between 1970 and 2012. A total of 160 papers that were relevant to the most common nonallergic drug hypersensitivity reactions were selected for discussion.

RESULTS

Nonallergic drug hypersensitivities do not involve either IgE-mediated (type 1) or delayed (type 4) hypersensitivity. Nonallergic hypersensitivities are commonly referred to as pseudoallergic or idiosyncratic reactions. The common nonallergic drug hypersensitivities are secondary to chemotherapeutic drugs, radiocontrast agents, vancomycin, nonsteroidal anti-inflammatory agents, local anesthetic reactions and opiates. Protocols for skin testing of radiocontrast, nonsteroidal anti-inflammatory agents, local anesthetics and chemotherapeutic agents have been developed, though most have not been validated or standardized. Other diagnostic tests include in vitro-specific IgE tests, and the current 'gold' standard is usually an oral challenge or bronchoprovocation test. In the case of aspirin, even though it is not believed to be IgE-mediated, a 'desensitization' protocol has been developed and utilized successfully, although the mechanism of this desensitization is unclear.

CONCLUSIONS

Diagnostic methods exist to distinguish allergic from nonallergic drug hypersensitivity reactions. The best option in nonallergic drug hypersensitivity is avoidance. If that is not possible, premedication protocols have been developed, although the success of premedication varies amongst drugs and patients.

Diagnostic evaluation of patients with nonimmediate cutaneous hypersensitivity reactions to iodinated contrast media

BACKGROUND

Nonimmediate hypersensitivity reactions to iodinated contrast media (CM) are common. Allergological evaluation is necessary to confirm the diagnosis and to find a tolerated alternative. The aim of this study was to establish the role of skin testing and the drug provocation test (DPT) in the diagnosis of nonimmediate reactions to CM.

METHODS

Skin intradermal testing and patch testing with delayed readings were carried out with different CM (iobitridol, iomeprol, iodixanol, iohexol, ioversol, iopramide and ioxaglate). Single-blind placebo-controlled DPT was carried out in those cases with a negative skin test. In seven cases, a skin biopsy was obtained from positive skin tests and positive DPT.

RESULTS

Of the 161 subjects evaluated, 34 (21.1%) were skin-test positive, 21 (50%) to Iomeprol, 7 (16.7%) to Iodixanol, 5 (11.9%) to Iobitridol, 4 (9.5%) to Ioxaglate, 3 (7.1%) to Iohexol and 1 (2.4%) to Iopramide. DPT was positive in 44 cases (34.6%) that were skin-test negative, 38 (76%) to Iodixanol, 8 (16%) to Iomeprol and 4 (8%) to Iohexol. Of 78 cases (48.4%) with confirmed hypersensitivity, 34 (43.6%) were identified by skin testing and 44 (56.4%) by DPT. Skin biopsies showed a perivascular mononuclear cell infiltrate, mainly in the dermis, with higher levels of CD4 than CD8 T lymphocytes, with expression of activation markers and skin homing receptors.

CONCLUSION

Patients with nonimmediate reactions to CM were identified by skin testing in 43.6% and by DPT in 56.4%. The method to confirm the diagnosis differed depending on the CM involved.

Immediate hypersensitivity reaction to gadolinium-based MR contrast media

PURPOSE

To determine the incidence and risk factors of immediate hypersensitivity reactions to gadolinium-based magnetic resonance (MR) contrast agents.

MATERIALS AND METHODS

Institutional review board approval and a waiver of informed consent were obtained. A retrospective study of patients who had been given gadolinium-based MR contrast media between August 2004 and July 2010 was performed by reviewing their electronic medical records. In addition to data on immediate hypersensitivity reaction, the kinds of MR contrast media and demographic data including age, sex, and comorbidity were collected. To compare the groups, the χ(2) test, Fisher exact test, χ(2) test for trend, Student t test, analysis of variance test, and multiple logistic regression test were performed.

RESULTS

A total of 112 immediate hypersensitivity reactions (0.079% of 141 623 total doses) were identified in 102 patients (0.121% of 84 367 total patients). Among the six evaluated MR contrast media, gadodiamide had the lowest rate (0.013%) of immediate hypersensitivity reactions, while gadobenate dimeglumine had the highest rate (0.22%). The rate for immediate hypersensitivity reactions was significantly higher in female patients (odds ratio = 1.687; 95% confidence interval: 1.143, 2.491) and in patients with allergies and asthma (odds ratio = 2.829; 95% confidence interval: 1.427, 5.610). Patients with a previous history of immediate hypersensitivity reactions had a higher rate of recurrence after reexposure to MR contrast media (30%) compared with the incidence rate in total patients (P < .0001). The incidence of immediate hypersensitivity reactions increased depending on the number of times patients were exposed to MR contrast media (P for trend = .036). The most common symptom was urticaria (91.1%), and anaphylaxis occurred in 11 cases (9.8%). The mortality rate was 0.0007% because of one fatality.

CONCLUSION

The incidence of immediate hypersensitivity reactions to MR contrast media was 0.079%, and the recurrence rate of hypersensitivity reactions was 30% in patients with previous reactions.

Surveillance of contrast-media-induced hypersensitivity reactions using signals from an electronic medical recording system

BACKGROUND

Contrast-media (CM) hypersensitivity is a well-known adverse drug reaction. Surveillance of adverse drug reactions usually depends on spontaneous reports. However, the rate of spontaneous reports is low. Recent progress in information technology enables the electronic search on signals of adverse drug reactions from electronic medical recording (EMR) systems.

OBJECTIVES

To analyze the incidence and clinical characteristics of CM hypersensitivity using an EMR-based surveillance system.

METHODS

The surveillance system used signals from standardized terms within the international classification of nursing practice terms that can indicate symptoms of CM hypersensitivity and from the order codes for procedures that used contrast media, antihistamine, and epinephrine. The search strategy was validated by allergists comparing the electronic search strategy versus manually reviewing medical charts over one month. The main study covered for one year period.

RESULTS

Detection rate of the electronic search method was 0.9% (7/759), while that of the manual search method was 0.8% (6/759). EMR-based electronic search method was highly efficient: reduced the charts that needed to be reviewed by 96% (28/759). The sensitivity of electronic screening was 66.7%, specificity was 99.6%, and the negative predictive value was 99.7%. CM hypersensitivity reactions were noted in 266 among 12,483 cases (2.1%). Urticaria was the most frequent symptom (74.4%). CT was the most frequent procedure (3.6%) that induced CM hypersensitivity.

CONCLUSION

A surveillance system using EMR may be a useful tool in the study of drug hypersensitivity epidemiology and may be used in an adverse drug reaction alarm system and as a clinical, decision making support system.

Transient small bowel angioedema due to intravenous iodinated contrast media

Three cases of transient proximal small bowel angioedema induced by intravenous administration of nonionic iodinated contrast media (CM) are presented. Computed tomography (CT) images in the venous phase displayed the proximal small bowel with circumferential thickening of the wall including the duodenum and proximal segment of the jejunum. The bowel wall was normal in non-enhanced images, and normal or inconspicuous in arterial phase enhanced images. In one of the three cases, the bowel wall was thickened in venous phase but disappeared in the 40 s delayed phase images. No filling defect was seen in the lumen of the superior mesenteric artery and vein. No peritoneal effusion or mesentery abnormality was found. Each of these patients reported only mild abdominal discomfort and recovered without specific treatment within a short time. Only one patient suffered mild diarrhea after scanning which had resolved by the following day. The transient anaphylactic small bowel angioedema due to intravenous iodinated contrast media was easily diagnosed based on its characteristic CT findings and clinical symptoms. Differential diagnosis may include inflammatory and ischemic bowel disease, as well as neoplasms. A three-phase CT protocol and good understanding of this disorder are fundamentally important in the diagnosis of this condition. The supposed etiology behind the transient anaphylactic reaction to intravenous administration of iodinated CM in small bowel is similar to other CM-induced hypersensitive immediate reactions. The predilection location of transient anaphylactic bowel angioedema is the small intestine, particularly the proximal segment. A speculated cause may be the richer supply of vessels in the small intestine, ample mucous folds and loose connective tissue in the duodenum and the jejunum.

A clinical study of cutaneous adverse reactions to nonionic contrast media in Korea

Background

The use of intravenous contrast media (CM) has increased for the diagnosis of several diseases. The newly developed low osmolar nonionic contrast agents cause significantly decreased adverse reactions than the higher osmolar ones. However, adverse reactions may still occur, ranging in severity from minor side effects to severe complications. However, there have been few reports about cutaneous adverse reactions (CARs) to nonionic monomer CM.

Objective

The purpose of this study was to evaluate clinical features of CAR to intravenous nonionic monomer CM.

Methods

A total 47,338 examinees underwent intravenous iodinated contrast-enhanced computed tomography scan using nonionic monomer CM. Among the adverse reactions to the CM, we divided them into cutaneous or noncutaneous and immediate (<1 hr) or late (≥1 hr) adverse reactions.

Results

Adverse reactions were noted in 62 cases out of the total 47,338 cases; 50 cases (80.7%) were categorized CARs. Among them, there were 24 male and 26 female patients. There was no significant difference between the sexes, and CARs occurred in all age groups. The highest occurrence was in the age range of 50~59 years. CARs included urticaria (78%), angioedema (10%), maculopapular rash (8%), erythema (2%), and pruritus without rash (2%). Immediate reactions were 92% (46 cases), while late reactions were 8% (4 cases).

Conclusion

CARs to nonionic monomer CM accounted for most of the adverse reactions (80.7%) and urticaria was the most common.

Perioperative allergy: uncommon agents

Anesthesia may often be considered as a high-risk procedure and anaphylaxis remains a major cause of concern for anesthetists who routinely administer many potentially allergenic agents. Neuromuscular blocking agents, latex and antibiotics are the substances involved in most of the reported reactions. Besides these three agents, a wide variety of substances may cause an anaphylactic reaction during anesthesia. Basically all the administered drugs or substances may be potential causes of anaphylaxis. Among them, those reported the most in literature include hypnotics, opioids, local anesthetics, colloids, dye, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), Iodinated Contrast Media (ICM), antiseptics, aprotinin, ethylene oxyde and formaldehyde, and protamine and heparins. No premedication can effectively prevent an allergic reaction and a systematic preoperative screening is not justified for all patients; nevertheless, an allergy specialist should evaluate those patients with a history of anesthesia-related allergy. Patients must be fully informed of investigation results, and advised to provide a detailed report prior to future anesthesia.

A world allergy organization international survey on diagnostic procedures and therapies in drug allergy/hypersensitivity

OBJECTIVE

To study the diagnostic and treatment modalities used in drug allergy/hypersensitivity among members of the World Allergy Organization (WAO).

METHODS

A questionnaire comprising 39 questions was circulated electronically to member societies, associate member societies, and regional and affiliate organizations of WAO between June 29, 2009, and August 9, 2009.

RESULTS

Eighty-two responses were received. Skin testing was used by 74.7%, with only 71.4% having access to penicillin skin test reagents. In vitro-specific IgE tests were used by 67.4%, and basophil activation test was used by 54.4%. Lymphocyte transformation tests were used by 36.8% and patch tests by 54.7%. Drug provocation tests were used by 68.4%, the most common indication being to exclude hypersensitivity where history/symptoms were not suggestive of drug hypersensitivity/allergy (76.9%). Rapid desensitization for chemotherapy, antibiotics, or biologic agents was used by 69.6%. Systemic corticosteroid was used in the treatment of Stevens-Johnson syndrome by 72.3%, and high-dose intravenous immunoglobulins in toxic epidermal necrolysis by 50.8%. Human leukocyte antigen screening before prescription of abacavir was used by 92.9% and before prescription of carbamazepine by 21.4%.

CONCLUSIONS

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 WAO member societies.

The use of gadolinium in patients with contrast allergy or renal failure requiring coronary angiography, coronary intervention, or vascular procedure

Coronary artery angiography remains an important procedure for the assessment of coronary arteries. It requires injection of iodinated contrast for the opacification of coronary arteries. Severe allergy to iodine contrast and renal insufficiency are two main problems with iodine-based contrast media. Gadolinium (Gd) has different chemical structure with no cross reactivity with iodine-based contrast media in patients with iodine allergy. The use of Gd is commonly used in contrast-enhanced magnetic resonance imaging for image enhancement, making it a potential alternative in patients in whom iodine is contraindicated. The aim of this manuscript is to review the available literature on the use of Gd in patients with contraindication to iodine contrast due to allergy or in patients with severe renal failure requiring coronary or vascular procedures.

Perioperative Anaphylaxis: Epidemiology

The clinical diagnosis of an anesthesia-related immediate hypersensitivity reaction is a difficult task for clinicians. Anaphylaxis may present as cardiovascular collapse or airway obstruction, associated or not with cutaneous manifestations. Drug hypersensitivity reactions that occur during anesthesia are responsible for significant morbidity and mortality and socio-economic costs. Perioperative anaphylaxis is becoming more common, probably because of the more frequent use of anesthesia and the increasing complexity of the drugs used. However, despite increased awareness of anaphylactic reactions to drugs and compounds used in anesthesia, their incidence remains poorly defined. Moreover, current epidemiological data should be carefully evaluated since the various studies published concerned non-homogeneous populations and gave differing definitions of drug hypersensitivity.

Perioperative Allergy: Risk Factors

Perioperative anaphylactic as well as anaphylactoid reactions can be elicited by drugs, diagnostic agents, antiseptics, disinfectants and latex. In some individuals, allergic reactions occur in the absence of any evident risk factor. Previous history of specific safe exposure to a product does not permit to exclude the risk of having a reaction. We have systematically reviewed characteristics in the patient's history or clinical parameters that affect the risk of developing reactions during anesthesia. Evidence shows that patients with previous unexplained reaction during anesthesia are at risk for perioperative allergic reactions. An allergic reaction to an agent is associated with previous reaction to a product that is related with the culprit agent. Multiple surgery procedures, professional exposure to latex and allergy to fruit are associated with an increased frequency of latex allergy. It has been shown that in some instances, allergic perioperative reactions may be more common in atopic patients and in female.

Hypersensitivity reactions to contrast media: prevalence, risk factors and the role of skin tests in diagnosis--a cross-sectional survey

BACKGROUND

Hypersensitivity to contrast media (CMs) may be common and serious.

AIM

To evaluate the prevalence of CM hypersensitivity, risk factors associated with it and the role of skin testing in its diagnosis.

METHODS

A structured questionnaire was administered to patients who underwent computed tomography during a 1-year period. Skin tests with CMs, including skin prick tests (SPTs), intradermal tests (IDTs) and patch tests (PTs), were conducted on CM reactors (n = 24). Volunteers who tolerated CM exposure or had never been exposed to any CMs served as controls (n = 37).

RESULTS

A total of 1,131 patients (630 females and 501 males; mean age 55 ± 14.2 years) were enrolled in the study. The prevalence of historical and current CM reactors was 33/1,131 (2.92%) and 8/1,105 (0.72%), respectively. The skin was the most affected site, with mild to moderate reactions. Female gender, a history of doctor-diagnosed asthma, drug allergy, food allergy and psychiatric diseases were significant risk factors. The sensitivities of SPTs and early readings of IDTs in the diagnosis of immediate reactions were 0 and 20%, respectively, and the specificities were 94.6 and 91.4%, respectively. For early readings of IDTs, the positive predictive value (PPV) and negative predictive value (NPV) were 40 and 80%, respectively. For nonimmediate reactions, the sensitivities of delayed readings of IDTs and PTs were 14.3 and 25%, respectively; specificity was 100% for both tests. The PPV was 100% for both of these tests, and the NPVs were 85.4 and 82.4%, respectively.

CONCLUSIONS

Our findings are comparable with the incidence, profile and risk factors associated with CM hypersensitivity reported previously. Skin testing with CMs has a high specificity, but its role in diagnosis is limited due to low sensitivity.

The role of iodine in hypersensitivity reactions to radio contrast media

INTRODUCTION

Hypersensitivity reactions to iodinated radio contrast media (RCM) are either immediate-type (IT) or delayed reactions (DT). In IT, the pathomechanism is unclear. In DT, delayed positive patch (PT) and intradermal tests (IDT) and RCM-specific T cells suggest a T cell-mediated mechanism. In both, the role of iodine has not been clarified; however, patients are often labelled as 'iodine allergic'. Occasionally, positive skin tests to iodine-containing drugs are observed.

OBJECTIVE

We investigated the presence of hypersensitivity to iodine in patients with a history of hypersensitivity reactions to RCM.

METHODS

Nineteen patients with a history of IT (n=9) or DT (n=10) to RCM were investigated. Skin prick tests, IDT and PT with several RCM and iodine formulations were carried out. All underwent oral provocation with Lugol's solution (LS). Two patients each with iodine mumps, contact dermatitis to iodized antiseptics and chronic idiopathic urticaria served as control or proof of concept.

RESULTS

In the IT group, skin tests were positive in three out of nine patients to one RCM. One patient with negative skin tests reacted twice to oral iodine with urticaria. In the DT group, sensitization to one or several RCM was identified in 10 out of 10 patients. In seven out of 10 patients, additional sensitizations to the iodine formulations were found. Two patients developed a mild exanthema after oral provocation with LS.

CONCLUSION

We have previously demonstrated in patients with iodine mumps that an oral challenge with LS is a valid means to elicit hypersensitivity reactions to iodine. In 19 patients, we showed that iodine is rarely the eliciting agent in hypersensitivity reactions to RCM. Only one patient with a late urticaria to an RCM with a late urticaria to LS and two patients with DT and broad sensitization to all RCM tested reacted to LS with an exanthema. In most cases, more likely the RCM molecules and not iodine are the eliciting compounds.

Outcomes of premedication for non-ionic radio-contrast media hypersensitivity reactions in Korea

BACKGROUND

Radio-contrast media (CM)-related adverse reactions are important clinical problems that may cause fatal anaphylaxis. Accordingly, it has been common practice to premedicate patients who have had previous reactions to CM with corticosteroids, antihistamines, and H2 blockers to prevent hypersensitive reactions. However, the effectiveness of premedication has not been properly demonstrated, especially in cases related to non-ionic CM. In this study, we evaluated the effectiveness of premedication at preventing of non-ionic CM immediate-type hypersensitivity reactions.

METHODS

A total of 30 patients who had been pretreated with corticosteroid and H1 antihistamines and/or H2 blockers in a 3-year period were enrolled. The results of premedication were evaluated in terms of clinical characteristics and the features of breakthrough reactions.

RESULTS

Hypersensitivity reactions were not prevented in 5 of the 30 patients who had experienced prior CM reactions (overall recurrence rate after premedication 16.7%; 4/17 patients with mild previous reactions, and 1/13 patients with severe previous reactions). The recurrence rate after premedication was significantly higher in patients with mild previous reactions than in those with severe reactions (23.5% vs. 7.7%; p<0.001). The breakthrough reactions were similar to the prior reactions in terms of severity and clinical manifestations.

CONCLUSION

Premedication with corticosteroid and H1 antihistamines and/or H2 blockers effectively prevent non-ionic CM-related adverse events in most patients who have had severe previous reactions to CM. However, physicians should be aware of the possibility of premedication failing and of breakthrough reactions, even in cases in which the previous reactions were mild.

Delayed cutaneous manifestations of drug hypersensitivity

Drugs may elicit a considerable variety of clinical signs, often affecting the skin and the mucous membranes. The most common are maculopapular exanthemas and urticaria, more rarely pustules, bullae vasculitic lesions, and lichenoid lesions may also be observed. Apart from the morphology, the chronology of the occurrence and the evolution of single skin lesions and exanthema are also paramount in the clinical diagnosis of cutaneous drug hypersensitivity. Often, the skin represents the only organ manifestation; however, it may be the herald for a systemic involvement of internal organs, such as in severe drug-induced hypersensitivity syndromes or anaphylaxis.

Looking ahead in dermatology: skin and allergy

The prevalence of allergic diseases has increased tremendously over the last decades. Clinically they comprise a spectrum of many different conditions caused by specific immunological hypersensitivity in response to a mostly apathogenic substance. Environmental factors such as lack of immune-stimulating contacts (infection, vaccination) and exposure to allergy-enhancing anthropogenic pollutants from tobacco smoke or traffic exhaust particles are suspected to be involved in the increase of allergies. Recently it has been shown that pollens are not only allergen carriers but also secrete highly active proinflammatory lipid mediators, pollen-associated lipid mediators (PALMs), which have proinflammatory and immuno-modulatory capacity that facilitates allergic sensitization of the skin and mucous membranes. The skin is one of the most important organs where allergic reactions manifest. Many different morphological and physiopathological entities can be observed in the skin that represent all kinds of pathogenetic immune reactions from immediate-type allergy, urticaria, angioedema, anaphylaxis, cytotoxic and immune complex reactions such as thrombocytopenic purpura or allergic leukocytoclastic vasculitis, exanthematous drug eruptions, granulomatous skin reactions to tattoos or fillers as well as a wide spectrum of dermatitis and eczema with allergic contact dermatitis being one of the most common occupational diseases in many countries. Recent progress in pathophysiology has revealed a role of epidermal barrier function as well as immunodeviation in atopic eczema giving rise to new diagnostic and therapeutic strategies. The interdisciplinary character of allergy implies a close cooperation between different disciplines where dermatology plays a major role in the management of allergic diseases, covering diagnostic, therapeutic and preventive aspects.

Processing-dependent and -independent pathways for recognition of iodinated contrast media by specific human T cells

BACKGROUND

One to three percent of patients exposed to intravenously injected iodinated contrast media (CM) develop delayed hypersensitivity reactions. Positive patch test reactions, immunohistological findings, and CM-specific proliferation of T cells in vitro suggest a pathogenetic role for T cells. We have previously demonstrated that CM-specific T cell clones (TCCs) show a broad range of cross-reactivity to different CM. However, the mechanism of specific CM recognition by T cell receptors (TCRs) has not been analysed so far.

OBJECTIVE

To determine how T cells specifically recognize CM.

METHODS

CM-specific TCCs were generated from human blood of three CM-allergic patients and a specific TCR was transfected into a mouse T cell hybridoma. Functional analysis such as proliferation assays, IL-2 secretion assays, and calcium influx experiments were performed using irradiated, glutaraldehyde-fixed, CM-pre-incubated, human leucocyte antigen (HLA)-DR-matched or -mismatched antigen-presenting cells (APCs), and HLA-blocking antibodies.

RESULTS

We identified two mechanisms of T cell stimulation: some TCCs and the transfectant reacted to CM independent of uptake by APCs because proliferation/IL-2 secretion occurred in the presence of glutaraldehyde-fixed APCs, and intracellular calcium increased within seconds after drug addition. Other TCCs required functional APCs, compatible with uptake and presentation of CM on MHC-class II molecules, as implied by three findings: (1) glutaraldehyde fixation of APCs abrogated presentation; (2) CM could not be washed away from CM-pre-incubated APCs; and (3) the optimal pulsing time was 10-20 h. Because allogeneic, MHC-matched, CM-pulsed APCs could induce proliferative responses as well, the ability of CM uptake and presentation is not unique to APCs from patients with CM-induced delayed hypersensitivity.

CONCLUSION

Our data suggest that CM may be stimulatory for T cells either by direct binding to the MHC-TCR complex or by binding after uptake and processing by APCs. This questions the assumed inert nature of CM.

[Drug patch tests in the investigation of cutaneous adverse drug reactions]

Cutaneous adverse drug reactions (CADR) are a frequent problem in clinical medicine. Since patients are often on multiple drug regimes, it is often difficult to pinpoint the relevant drug from history alone. Besides clinical and chronological parameters, patch testing with the suspected compound has been reported as helpful in determining the cause of a CADR and in studying the physiopathological mechanisms involved in such reactions. The key advantage of drug patch tests is that they can be performed using any commercialized form of drugs and without hospital surveillance because they only rarely induce adverse reactions, which in any event are mild. The method for performing drug patch tests has been described, and requisite commercialized material is now commercially available, failing which the best approach is to dilute the drug in its commercialized form at 30% in petrolatum or in water. The results of drug patch tests depend on the drug tested and the clinical features of the initial CADR. They appear to be of value in investigating maculopapular rash, eczema at drug injection sites, photosensitivity (photopatch tests with 5J of irradiation), fixed drug eruption (testing at the sequelae site), acute generalized exanthematous pustulosis and symmetrical drug-related intertriginous flexural exanthema. Although less widely used, they are probably also of value in drug reaction with eosinophilia and systemic symptoms (DRESS) but they are of less use in Stevens-Johnson syndrome (SSJ) and Lyell's syndrome. Many drugs have been reported as producing positive patch tests, and most of these are summarized in a summary table of this literature review.

Skin testing in patients with hypersensitivity reactions to iodinated contrast media - a European multicenter study

BACKGROUND

Iodinated contrast media cause both immediate and nonimmediate hypersensitivity reactions. The aim of this prospective study was to determine the specificity and sensitivity of skin tests in patients who have experienced such reactions.

METHODS

Skin prick, intradermal and patch tests with a series of contrast media were conducted in 220 patients with either immediate or nonimmediate reaction. Positive skin tests were defined according to internationally accepted guidelines. Seventy-one never-exposed subjects and 11 subjects who had tolerated contrast medium exposure, served as negative controls.

RESULTS

Skin test specificity was 96-100%. For tests conducted within the time period from 2 to 6 months after the reaction, up to 50% of immediate reactors and up to 47% of nonimmediate reactors were skin test positive. For immediate reactors, the intradermal tests were the most sensitive, whereas delayed intradermal tests in combination with patch tests were needed for optimal sensitivity in nonimmediate reactors. Contrast medium cross-reactivity was more common in the nonimmediate than in the immediate group. Interestingly, 49% of immediate and 52% of nonimmediate symptoms occurred in previously unexposed patients. Many of these patients were skin test positive, indicating that they were already sensitized at the time of first contrast medium exposure.

CONCLUSIONS

These data suggest that at least 50% of hypersensitivity reactions to contrast media are caused by an immunological mechanism. Skin testing appears to be a useful tool for diagnosis of contrast medium allergy and may play an important role in selection of a safe product in previous reactors.

Pharmacovigilance of drug allergy and hypersensitivity using the ENDA-DAHD database and the GALEN platform. The Galenda project

Nonallergic hypersensitivity and allergic reactions are part of the many different types of adverse drug reactions (ADRs). Databases exist for the collection of ADRs. Spontaneous reporting makes up the core data-generating system of pharmacovigilance, but there is a large under-estimation of allergy/hypersensitivity drug reactions. A specific database is therefore required for drug allergy and hypersensitivity using standard operating procedures (SOPs), as the diagnosis of drug allergy/hypersensitivity is difficult and current pharmacovigilance algorithms are insufficient. Although difficult, the diagnosis of drug allergy/hypersensitivity has been standardized by the European Network for Drug Allergy (ENDA) under the aegis of the European Academy of Allergology and Clinical Immunology and SOPs have been published. Based on ENDA and Global Allergy and Asthma European Network (GA(2)LEN, EU Framework Programme 6) SOPs, a Drug Allergy and Hypersensitivity Database (DAHD((R))) has been established under FileMaker((R)) Pro 9. It is already available online in many different languages and can be accessed using a personal login. GA(2)LEN is a European network of 27 partners (16 countries) and 59 collaborating centres (26 countries), which can coordinate and implement the DAHD across Europe. The GA(2)LEN-ENDA-DAHD platform interacting with a pharmacovigilance network appears to be of great interest for the reporting of allergy/hypersensitivity ADRs in conjunction with other pharmacovigilance instruments.