Continued need of appropriate betalactam-derived skin test reagents for the management of allergy to betalactams

Drug reintroduction testing and beta-lactam hypersensitivity in children: Protocols and results, a 12-year experience

Introduction: Oral provocation test (OPT) to beta-lactam antibiotics (BL) is a gold standard in allergology investigation. We aimed to demonstrate the contribution of OPT in BL hypersensitivity (HS) indicated as a first step in diagnosis. Methods: We conducted a retrospective study from 2007 to 2019, in a single Tunisian tertiary care academic center. It concerned children with presumed non-severe allergic manifestations to BL, with a reaction that has occurred at least 6 months before the OPT. Results: We identified 35 children for inclusion. After the first OPT, a second OPT with a different BL was performed in case of a positive result of the first one. In 12 cases (34.2%), the OPT elicited a reaction. In eight cases the allergy was to penicillin and in two cases to cephalosporins (cefixim). Cross-reactivity was noted in two cases. Conclusion: An OPT to BL indicated in the first instance in non-severe reaction in children will allow a rapid diagnosis in case of suspicion of HS to BL.

Isolierte Zungenschwellung nach Penizillin und negative Allergieabklärung – alles in Butter?

Penizilline können alle Arten spezifischer Immunreaktionen nach der erweiterten Coombs- und Gell-Klassifikation auslösen und zählen zu den häufigsten Ursachen unerwünschter Arzneimittelreaktionen. Das diagnostische Armamentarium umfasst neben den verschiedenen Hauttesten den Nachweis spezifischer IgE gegen allergene Determinanten am Betalaktam-Molekül und ggf. zelluläre Aktivierungsteste. Im Fall negativer Ergebnisse bei den genannten Testen kann ggf. noch die Toleranz im Rahmen eines Provokationstestes nachgewiesen werden. Die Sensitivität der diagnostischen Teste ist – mit Ausnahme des Provokationstests – aber limitiert, und falsch negative Teste sind möglich. Wir präsentieren zwei Fälle mit einer isolierten Zungenschwellung nach Gabe von Amoxicillin bei vollständig negativem, wiederholtem allergologischen Work-up. Bei beiden Patienten konnte die Überempfindlichkeit nur mit einer Reexposition nachgewiesen werden.

Descriptive analysis of a simplified approach to low-risk drug hypersensitivity reactions

BACKGROUND

Evaluation of drug allergy is intricate because of nonstandardized testing and challenge method variability.

OBJECTIVE

To determine the clinical and epidemiologic characteristics of a large group of patients with suspected drug allergies who underwent 1 or more provocation tests (PT), and to establish whether performing this test in fewer steps is safe and effective.

METHODS

A cross-sectional descriptive study was conducted in patients with suspected drug allergies who underwent a provocation test at the allergy service of Fundación Valle del Lili, Cali, Colombia, from January 2011 to August 2017.

RESULTS

A total of 508 patients underwent 615 PTs; the median age was 34.5 years (range, 1-87 years) and 332 were women (65.3%). The most frequently implicated drugs were nonsteroidal anti-inflammatory drugs in 362 patients (58.9%), followed by beta-lactam antibiotics in 170 (27.6%), and non-beta-lactam antibiotics in 21 (3.4%). The most typically described manifestations were cutaneous urticaria in 282 patients (45.8%) and angioedema in 220 (35.7%). Most patients underwent the PT without performing other previous tests, which were done in only 92 patients (18.3%). Skin prick tests and intradermal reaction tests were performed in 81 patients (15%); all results were negative. In 519 patients (84.3%), the PT was performed in 2 steps without a placebo. Of the PTs performed in 2 steps, 492 (94.8%) had negative results. In addition, PT was performed in 195 patients (37.6%) in whom 2 equal doses of the drug was administered; 186 patients (95.4%) had negative results.

CONCLUSION

Performing an open PT (without previous tests) in 2 steps among patients with low-risk drug reactions is safe. However, every case must be analyzed individually in terms of the risk-benefit ratio.

Immediate cephalosporin allergy

BACKGROUND

Patients who suffer from acute IgE-mediated allergy to a cephalosporin antibiotic are frequently assumed to be at high risk of allergy to other cephalosporins and penicillins.

AIM

To define cross-reactivity patterns in patients with confirmed allergy to a cephalosporin.

METHODS

Subjects presenting with a history of immediate allergy to a cephalosporin-family antibiotic between March 2009 and July 2017 were investigated with specific IgE testing to penicillin, amoxycillin and cefaclor, followed by skin prick testing, intradermal testing and drug provocation testing with a panel of penicillins and cephalosporins.

RESULTS

Out of 564 subjects with a reported beta-lactam allergy, 90 identified a cephalosporin as their index drug. Fifty-five (61.1%) of the 90 subjects tested had a history consistent with an IgE-mediated reaction, of whom 24 (43.6%) were proven to be allergic to their index cephalosporin. Twenty (83.3%) of the 24 were allergic only to their index cephalosporin. Of the four remaining subjects, two were co-sensitised to another beta-lactam with a similar side chain, while the other two had no specific cross-reactivity pattern. Major and minor penicillin determinants were negative for all cephalosporin-allergic individuals.

CONCLUSION

In our cohort, cephalosporin allergy does not appear to be a class effect, with most cases found allergic only to their index cephalosporin. Co-sensitisation to other cephalosporins or penicillins was uncommon, and when it occurred, was usually consistent with side chain cross-reactivity.

A novel whole blood based method for lymphocyte transformation test in drug allergies

Drug allergies pose a great deal of danger for the patients. It hinders effective treatment procedures in hospitalized patients. Moreover, it complicates the symptoms due to the allergic reactions of the immune system. Allergic reactions may arise against any medication including antibiotics and chemotherapeutics. Therefore, it is crucial to assess the sensitization pattern of the patients to culprit drug(s) before retreatment with the same or similar drug, or in order to confirm/exclude a suspected drug hypersensitivity reaction. In vivo and in vitro tests are performed in the evaluation of patients. Current methods of in vitro drug allergy evaluations rely on time consuming and expensive methods. Ficoll separation of peripheral blood mononuclear cells, their activation with stimulants in the presence of the drug of interest, CD69 or CD25 or BrdU or radioactive thymidine analysis of the cells after a couple of days of incubation is an excessively elaborate work and also uneconomical. Moreover, it requires a great deal of expertise to interpret the results. Here, we are reporting a new whole blood based lymphocyte transformation test method that does not require ficoll separation, CD69, CD25, BrdU and radioactive thymidine analysis. Thanks to the color change in the whole blood itself one can easily determine the allergic reaction to a certain drug. This new method is less time consuming, more economical and easy to apply.

Disparities in rate, triggers, and management in pediatric and adult cases of suspected drug-induced anaphylaxis in Canada

INTRODUCTION

Data is sparse on drug-induced anaphylaxis (DIA) and there have not been studies assessing the differences in clinical characteristics and management of DIA between adults and children.

OBJECTIVE

We assessed the percentage, diagnosis, and management of DIA among all anaphylaxis visits in three pediatric and one adult emergency departments (ED) across Canada.

METHODS

Children presenting to the Montreal Children's Hospital (MCH), British Columbia Children's Hospital (BCCH), and Children's Hospital at London Health Sciences Center and adults presenting to Hôpital du Sacré-Coeur with anaphylaxis were recruited as part of the Cross-Canada Anaphylaxis Registry. A standardized data form documenting the reaction and management was completed and patients were followed annually to determine assessment by allergist and use of confirmatory tests.

RESULTS

From June 2012 to May 2016, 51 children were recruited from the pediatric centers and 64 adults from the adult center with drug-induced anaphyalxis. More than half the cases were prospectively recruited. The percentage of DIA among all cases of anaphylaxis was similar in all three pediatric centers but higher in the adult center in Montreal. Most reactions in children were triggered by non-antibiotic drugs, and in adults, by antibiotics. The majority of adults and a third of children did not see an allergist after the initial reaction. In those that did see an allergist, diagnosis was established by either a skin test or an oral challenge in less than 20% of cases.

CONCLUSIONS

Our results reveal disparities in rate, culprit, and management of DIA in children versus adults. Further, most cases of suspected drug allergy are not appropriately diagnosed. Guidelines to improve assessment and diagnosis of DIA are required.

A retrospective comparison of false negative skin test rates in penicillin allergy, using pencilloyl-poly-lysine and minor determinants or Penicillin G, followed by open challenge

Background

A history of penicillin allergy in patients is common, but only 10–15 % are truly allergic. While the gold standard for diagnosing penicillin allergy is challenge, it is not recommended that this be done without first carrying out diagnostic skin testing. This is carried out with the major determinant benzylpenicilloyl (PPL) and the minor determinant mixture (MDM), consisting of penilloate, penicilloate and Penicillin G. However, since availability of the MDM is limited, Penicillin G alone has been used.

Methods

A retrospective chart review was carried out on patients tested for penicillin allergy in the Clinical Immunology and Allergy Clinic at the Health Sciences Centre, Winnipeg, Canada between 2005 and 2013. A total of 521 patients charts were reviewed, of whom 240 had skin testing, ImmunoCap^® for IgE to Penicillin G and V and had oral challenges with penicillin, amoxicillin or cloxacillin.

Results

17/240 (7.5 %) were skin test positive, 8 to PPL, 4 to MDM and 5 to Penicillin G. One was also positive on ImmunoCap^® testing. Three patients had negative skin tests but weakly positive ImmunoCap^®. 222 patients with negative skin tests and serological tests were challenged. Of these, 12 patients reacted to challenge. Three of the challenges were equivocal. Of the nine patients with definite positive challenges, three were tested with Penicillin G and six with MDM. Therefore the false negative rates for testing were 2.3 % with PPL and Penicillin G and 6.97 % for PPL and MDM. The difference was not significant (p = 0.0856).

Conclusions

In this group of patients with a history of penicillin allergy tested with the major determinant of benzyl penicillin and either MDM or Penicillin G, there was no difference in the rate of false negative testing, based on oral penicillin challenges. Therefore, Penicillin G can be safely used as an alternative to MDM in diagnosing penicillin allergy.

Management of allergy to penicillins and other beta-lactams

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

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.

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.

Overview of penicillin allergy

Allergy to penicillin is the most commonly reported antibiotic allergy. However, most patients who report a positive history of a prior reaction to penicillin are not found to be allergic to penicillin upon skin testing. Often, this history is vague or based on a parent's recollection of an event that occurred in the distant past. Avoidance of penicillin based on self-reported allergic history alone often leads to the use of an alternate antibiotic with greater cost or side effect profile. Patients with a negative skin test to both major and minor determinants may generally be given penicillin, with a statistical risk of developing an allergic reaction similar to that observed in the general population. A more cautious approach in these cases where the degree of suspicion is low, an allergic etiology is unproven, or there is a negative skin test, is to do a graded challenge. If the skin test is positive, an alternate antibiotic should be used. If, however, an alternate antibiotic is not available, then desensitization may be performed, but there are limitations to desensitization as well, and tolerance is not permanent. Avoidance of cephalosporins may be recommended in cases of penicillin allergy, but newer generation cephalosporins have demonstrate less cross-reactivity to penicillin than earlier generation ones. Desensitization protocols for cephalosporins are available but not standardized. The mechanisms of antibiotic sensitization are not clearly understood.

Immunologic evaluation of drug allergy

Hypersensitivity drug reactions (HDR) consist of an individual abnormal response with the involvement of the immunological system. In addition to specific immunological mechanisms where specific antibodies or sensitised T cells participate, release of inflammatory mediators by non-specific immunological recognition may also occur. Within this category are one of the most common groups of drugs, the non-steroidal anti-inflammatory drugs. In addition to chemical drugs new emerging ones with an increasing protagonism are biological agents like humanised antibodies and others. For IgE dependent reactions both in vivo and in vitro tests can be used for the immunological evaluation. Sensitivity of these is not optimal and very often a drug provocation test must be considered for knowing the mechanism involved and/or establishing the diagnosis. For non-immediate reactions also both in vivo and in vitro tests can be used. Sensitivity for in vivo tests is generally low and in vitro tests may be needed for the immunological evaluation. Immunohistochemical studies of the affected tissue enable a more precise classification of non-immediate reactions. The monitorization of the acute response of the reactions has given clues for understanding these reactions and has promising results for the future of the immunological evaluation of HDR.

The current practice of skin testing for antibiotics in Korean hospitals

BACKGROUND/AIMS

Antibiotic skin testing is a useful procedure for identifying patients with IgE-mediated hypersensitivity to antibiotics. The procedures, however, have not been standardized, and the testing is performed with diverse protocols in Korean hospitals wards. Thus, we examined the current practice of antibiotic skin testing in Korea.

METHODS

We sent questionnaires to 12 allergists working in secondary or tertiary referral hospitals and collected them by e-mail or fax. The questionnaire included items such as the types and concentrations of the tested antibiotics, the methods of antibiotic skin testing, and the interpretation of the results.

RESULTS

All hospitals responded to the questionnaire. The antibiotic skin testing protocols were variable, inconsistent, and differed with regard to the type and concentrations of antibiotics, the volume injected, and the interpretation of the results. Moreover, the protocols differed from the commonly recommended procedures in the medical literature.

CONCLUSIONS

Standardized guidelines for antibiotic skin testing are needed for the safe and effective use of antibiotics in Korea.

The use of penicillin skin testing to assess the prevalence of penicillin allergy in an emergency department setting

STUDY OBJECTIVE

Patient-reported penicillin allergies are often unreliable and can result in unnecessary changes in antibiotic therapy. Although penicillin allergy skin testing is commonly performed in allergy clinics, it has not been used in emergency departments (EDs) to verify self-reported allergies. We hypothesize that ED-based testing is possible and that the false-positive rate of patients with self-reported penicillin allergy are greater than 90%.

METHODS

This prospective observational cohort study enrolled a convenience sample of ED patients with a self-reported penicillin allergy. Patients were enrolled by one of 2 emergency physicians who performed skin prick and intracutaneous tests with penicillin major and minor determinants. The total testing time was 30 minutes. The proportion of false-positive self-reported allergies was computed with 95% confidence intervals (CIs) by using the score method.

RESULTS

A total of 150 patients (mean age 42 years; SD 16 years; 46% men; 47% black) were enrolled. The false-positive rate for self-reported penicillin allergy was 137 of 150 (91.3%; 95% CI 85.3% to 95.1%). There were no adverse reactions associated with penicillin skin testing. Compared with patients with a false-positive penicillin allergy result (confirmed by negative penicillin skin testing result), patients reporting a true penicillin allergy confirmed by positive penicillin skin test results tended to be more frequently men (61.5% versus 44.5%; Delta 17.0%; 95% CI -13.5% to 42%), black (69.2% versus 44.5%; Delta 24.7%; 95% CI -6.9% to 46.8%), and have no family history of drug allergy (7.7% versus 17.5%; Delta9.8%; 95% CI -20.9% to 20.4%), but self-reported other drug allergies more frequently (61.5% versus 38.7%; Delta 22.9%; 95% CI -7.7% to 47.5%).

CONCLUSION

Penicillin skin testing is feasible in the ED setting. A substantial number of patients who self-report a penicillin allergy do not exhibit immunoglobulin E-mediated sensitization to penicillin major and minor determinants. Penicillin testing in the ED may allow the use of more appropriate antibiotics for patients presenting with a history of penicillin allergy.

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.

[Allergy to betalactams: myth and realities]

Allergic reactions to penicillins have been reported since the 1950s, shortly after their introduction as therapeutic agents. An increasing number of reported anaphylactic reactions and other adverse effects proved this to be a serious public health problem. Fifty years later, betalactam-induced hypersensitivity is the most frequent cause of drug reaction and has been the source of a great number of publications. Clinically, betalactam-induced allergic reactions may be immediate or non-immediate according to the time interval between drug intake and the occurrence of symptoms. The diagnosis of betalactam hypersensitivity is based on skin tests methods, in vitro tests and drug provocation test. There are three classical methods for skin testing: prick, intradermal, and patch. These tests are still the most sensitive techniques. In vitro tests, mainly based on the quantification of IgE antibodies to betalactams by immunoassay (Fluorescent Enzyme Immunoassay [FEIA]), may sometimes yield useful complementary information. Drug provocation tests must be performed with the required caution and the adequate indication. Algorithms are available for both immediate and non-immediate reactions to provide a practical approach for patient evaluation. They are based on the following data: clinical history, skin tests, FEIA, and drug provocation tests. Finally, cross reactivity between betalactams has been reported, especially between penicillins and cephalosporins. Their frequency was long over-estimated, but recent evidence, indicates that cross reactivity between betalactams has become rare. Administration of cephalosporins in patients with a history of penicillin allergy requires performing skin testing with penicillin, the probably allergenic drug, and the cephalosporin to be prescribed.

Recent advances in the diagnosis of drug allergy

PURPOSE OF REVIEW

The present review addresses the most recent literature regarding the diagnosis of drug hypersensitivity reactions, which can be classified as immediate or nonimmediate according to the time interval between the last drug administration and the onset. Immediate reactions occur within 1 h; nonimmediate ones occur after more than 1 h.

RECENT FINDINGS

Clinical and immunological studies suggest that type-I (IgE-mediated) and type-IV (cell-mediated) pathogenic mechanisms are involved in most immediate and nonimmediate reactions, respectively. New diagnostic tools, such as the basophil activation test and the lymphocyte activation test, have been developed and are under validation.

SUMMARY

In diagnosis, the patient's history is fundamental; the allergologic examination includes in-vivo and in-vitro tests selected on the basis of the clinical features. Prick, patch, and intradermal tests are the most readily available forms of allergy testing. Determination of specific IgE levels is still the most common in-vitro method for diagnosing immediate reactions. The sensitivity of allergologic tests is not 100%; in selected cases, therefore, provocation tests are necessary. The routine use of the basophil activation test and the lymphocyte activation test could increase the sensitivity of diagnostic work-ups, thus reducing the need for drug provocation tests.