Clinical presentation and time course in hypersensitivity reactions to beta-lactams

Oral Challenge without Penicillin Skin Tests in Children with Suspected Beta-Lactam Hypersensitivity

Objective A misdiagnosed “penicillin allergy” is a common problem in childhood. Recently, skipping skin tests (STs) and performing a direct oral challenge test (OCT) have become an increasingly common approach in children with suspected β-lactam (BL) allergy. In our study, we aimed to evaluate the safety and efficacy of OCT without using ST in children who had a history of hypersensitivity reactions with BL antibiotics.

Materials and Methods We retrospectively evaluated direct OCT outcomes in children with both nonimmediate and immediate-type reaction history with BL antibiotics. STs were not performed before the challenge test. The patients were monitored for 4 hours after the challenge and continued using the drug in two divided doses for 3 days at home.

Results In this study, 72 patients were included, with median age of 7 years (interquartile range: 4; min: 1 year to max: 16 years), and of these, 56% were male. Forty-five subjects (63%) reported immediate-type adverse reactions. The most common clinical manifestation was urticaria/angioedema (51%, n: 37) and maculopapular exanthema in 46% (n: 33) of patients, respectively. The most commonly suspected drug was 71% amoxicillin-clavulanate. A 3-day OCT without preceding ST was performed in all patients. Only three patients (4.2%) showed a positive response to the oral drug challenge test. None of these reactions observed was more severe than index reactions.

Conclusion Performing OCT without STs is a safe and convenient method to exclude BL hypersensitivity in the pediatric age group.

An EAACI Task Force report on allergy to beta-lactams in children: Clinical entities and diagnostic procedures

Beta-lactam (BL) allergy suspicion is common in children and constitutes a major public health problem, with an impact on patient's health and on medical costs. However, it has been found that most of these reactions are not confirmed by a complete allergic workup. The diagnostic value of the currently available allergy tests has been investigated intensively recently by different groups throughout the world. This has led to major changes in the management of children with a suspected BL allergy. Particularly, it is now well accepted that skin tests can be skipped before the drug provocation test in children with a benign non-immediate reaction to BL. However, there is still a debate on the optimal allergic workup to perform in children with a benign immediate reaction. In addition, management of children with severe cutaneous adverse drug reactions remains difficult. In this review, based on a selection of the most relevant studies found in the literature, we will review and discuss the diagnosis of different forms of BL allergy in children.

Development of an Improved T-cell Assay to Assess the Intrinsic Immunogenicity of Haptenic Compounds

The prediction of drug hypersensitivity is difficult due to the lack of appropriate models and known risk factors. In vitro naïve T-cell priming assays that assess immunogenicity have been developed. However, their application is limited due requirements for 2 batches of autologous dendritic cells (DC) and inconsistent results; a consequence of single well readouts when exploring reactions where compound-specific T-cell frequency is undefined. Hence, we aimed to develop an improved, but simplified assay, termed the T-cell multiple well assay (T-MWA), that permits assessment of drug-specific activation of naïve T cells, alongside analysis of the strength of the induced response and the number of cultures that respond. DC naïve T-cell coculture, depleted of regulatory T cells (Tregs), was conducted in up to 48 wells for 2 weeks with model haptens (nitroso sulfamethoxazole [SMX-NO], Bandrowski's base [BB], or piperacillin [PIP]). Cultures were rechallenged with hapten and T-cell proliferation was measured using [3H]-thymidine incorporation. Priming of naïve T cells was observed with SMX-NO, with no requirement for DC during restimulation. Greater than 65% of cultures were activated with SMX-NO; with 8.0%, 30.8%, and 27.2% characterized as weak (stimulation index [SI] =1.5-1.9), moderate (SI = 2-3.9), and strong responses (SI > 4), respectively. The number of responding cultures and strength of the response was reproducible when separate blood donations were compared. Coinhibitory checkpoint blockade increased the strength of the proliferative response, but not the number of responding cultures. Moderate to strong priming responses were detected with BB, whereas PIP stimulated only a small number of cultures to proliferate weakly. In drug-responsive cultures inducible CD4+CD25+FoxP3+CD127low Tregs were also identified. To conclude, the T-MWA offers improvements over existing assays and with development it could be used to study multiple HLA-typed donors in a single plate format.

Accuracy of penicillin allergy diagnostic tests: A systematic review and meta-analysis

BACKGROUND

Having a penicillin allergy label associates with a higher risk for antibiotic resistance and increased health care use.

OBJECTIVE

We sought to assess the accuracy of skin tests and specific IgE quantification in the diagnostic evaluation of patients reporting a penicillin/β-lactam allergy.

METHODS

We performed a systematic review and diagnostic accuracy meta-analysis, searching on MEDLINE, Scopus, and Web of Science. We included studies conducted in patients reporting a penicillin allergy and in whom skin tests and/or specific IgE quantification were performed and compared with drug challenge results. We quantitatively assessed the accuracy of diagnostic tests with bivariate random-effects meta-analyses. Meta-regression and subgroup analyses were performed to explore causes of heterogeneity. Studies' quality was evaluated using QUADAS-2 criteria.

RESULTS

We included 105 primary studies, assessing 31,761 participants. Twenty-seven studies were assessed by bivariate meta-analysis. Skin tests had a summary sensitivity of 30.7% (95% CI, 18.9%-45.9%) and a specificity of 96.8% (95% CI, 94.2%-98.3%), with a partial area under the summary receiver-operating characteristic curve of 0.686 (I² = 38.2%). Similar results were observed for subanalyses restricted to patients reporting nonimmediate maculopapular exanthema or urticaria/angioedema. Specific IgE had a summary sensitivity of 19.3% (95% CI, 12.0%-29.4%) and a specificity of 97.4% (95% CI, 95.2%-98.6%), with a partial area under the summary receiver-operating characteristic curve of 0.420 (I² = 8.5%). Projected predictive values mainly reflect the low frequency of true penicillin allergy.

CONCLUSIONS

Skin tests and specific IgE quantification appear to have low sensitivity and high specificity. Because current evidence is insufficient for assessing the role of these tests in stratifying patients for delabeling, we identified key requirements needed for future studies.

A Critical Evaluation of Safety Signal Analysis Using Algorithmic Standardised MedDRA Queries

INTRODUCTION

Algorithmic Standardised MedDRA^® Queries (aSMQs) are increasingly used to enhance the efficiency of safety signal detection. The manner that aSMQs affect capture of potential safety cases is unclear.

OBJECTIVES

Our objective was to characterise the performance of aSMQs with respect to their potential for double counting, the likelihood of events in aSMQ positive cases being clinically related, how frequently terms are used for algorithmically positive cases, and the face validity of positive cases based on the drug inducing events. We were also interested in what effect requiring symptoms to overlap temporally would have on performance.

METHODS

We reviewed adverse event (AE) datasets of New Drug Applications and Biological License Applications and compiled a database including preferred terms and corresponding SMQs, SMQ term categories, AE start day, AE duration, drug name, and Anatomical Therapeutic Chemical class. Two reviewers independently determined if the algorithm was met and, if so, whether the broad terms overlapped temporally.

RESULTS

A total of 107 marketing applications were reviewed, including 103,928 patients and 277,430 AEs. Use of algorithms condensed the number of AEs to between 5 and 8% and the incidence to about 1.5% relative to when the SMQs are used without the algorithm. Certain aSMQs exhibited a potential for overcounting. Requiring symptoms to temporally overlap helped to eliminate irrelevant cases.

CONCLUSIONS

Our findings demonstrate that algorithmic and temporal assessment increased specificity of case retrieval, though the reduction in the number of terms or incidence seemed excessive for certain aSMQs. Evaluating the day of AE onset and duration improve specificity through identification of outlying events. Identification of drug classes known to cause the aSMQ's clinical condition provides face validity for this tool, yet detection of cases associated with novel classes may provide new understanding of these disorders. Improvements in some of the SMQ term lists may improve the performance of SMQs in general.

Pro and Contra: Provocation Tests in Drug Hypersensitivity

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

Chlorhexidine allergy in four specialist allergy centres in the United Kingdom, 2009-13: clinical features and diagnostic tests

We describe an observational survey of diagnostic pathways in 104 patients attending four specialist allergy clinics in the United Kingdom following perioperative hypersensitivity reactions to chlorhexidine reactions. The majority were life-threatening. Men undergoing urological or cardiothoracic surgery predominated. Skin prick testing and specific immunoglobulin (sIg)E testing were the most common tests used for diagnosis. Fifty-three per cent of diagnoses were made on the basis of a single positive test. Where multiple tests were performed the sensitivity of intradermal, basophil activation and skin prick testing was 68% (50-86%), 50% (10-90%) and 35% (17-55%), respectively. Seven per cent were negative on screening tests initially, and 12 cases were only positive for a single test despite multiple testing. Intradermal tests appeared most sensitive in this context. Additional sensitization to other substances used perioperatively, particularly neuromuscular blocking agents (NMBA), was found in 28 patients, emphasizing the need to test for possible allergy to all drugs to which the patient was exposed even where chlorhexidine is positive.

Prevention of Allergic Reactions in Anesthetized Patients

Hypersensitivity reactions during perioperative period are increasing and may be potentially life-threatening. Therefore, major emphasis is given to prevention. We perform a review to examine which measures should be taken to prevent reactions to products used in elective and emergency surgery. Any patient with a history of previous anaphylaxis or severe reaction during anaesthesia should be referred to allergist for detection of the offending compound. However, the identification of the triggering agent is not always feasible because of the low accuracy of diagnostic tests. In these cases and when emergency surgery is required, it should be considered to replace all drugs administered before the onset of the reaction with alternatives. Furthermore, any cross-reacting agent and latex, especially in patients belonging to populations at-risk for latex allergy should be avoided. In susceptible patients, premedication with antihistamines and corticosteroids might reduce the severity of reaction to drugs or contrast material while it is unclear whether pre-treatment decreases incidence of anaphylactic reactions. There is no evidence that premedication prevents allergic reactions to latex. Overall, physicians should not rely on the efficacy of premedication.

Interleukin-4 and interferon-γ are possible allergic markers in pediatric patients with β-lactam hypersensitivity

Background:

β-lactam agents are known to elicit T-cell-mediated immune responses that play a central role in the onset of allergic reactions, but the involvement of specific type of cytokines in drug allergy remains largely unexplored in humans.

Objectives:

This study was undertaken to investigate the role of cytokines involvement in pediatric patients with β-lactam hypersensitivity and to determine whether involvement of cytokines in drug-mediated reactions are important for the perspective of allergic patient's management.

Methods:

β-lactam-induced hypersensitivity reactions in eighty pediatric patients were determined by clinical manifestations and skin prick or intradermal testing. Production of T-helper (Th) type-1 cytokine interferon (INF)-γ, Th-2 cytokine interleukin (IL)-4, regulatory T-cell cytokine IL-10, and other cytokines IL-6 and IL-12 were determined by sandwich ELISAs.

Results:

Diagnosis of β-lactam allergy was confirmed in 53 pediatric patients. IL-4 secretion in patients' sera was significantly higher as compared with healthy controls (P < 0.05). However, INF-γ level in patients' sera was significantly lower as compared with controls (P < 0.05). No significant alterations were found in the protein secretion of IL-10, IL-12, and IL-6 in allergic patients as compared with controls (P > 0.05).

Conclusion:

We conclude that IL-4 is specific marker for the diagnosis of β-lactam-induced hypersensitivity. Moreover, IL-4 in combination with INF-γ is more sensitive for the diagnosis of these reactions. This study also concludes that both IL-4 and INF-γ may play an active role in the onset of allergic reactions against β-lactam antibiotics.

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 epidemiology of anaphylaxis in Europe: a systematic review

BACKGROUND

Anaphylaxis is an acute, potentially fatal, multi-organ system, allergic reaction caused by the release of chemical mediators from mast cells and basophils. Uncertainty exists around epidemiological measures of incidence and prevalence, risk factors, risk of recurrence, and death due to anaphylaxis. This systematic review aimed to (1) understand and describe the epidemiology of anaphylaxis and (2) describe how these characteristics vary by person, place, and time.

METHODS

Using a highly sensitive search strategy, we identified systematic reviews of epidemiological studies, descriptive and analytical epidemiological investigations, and studies involving analysis of routine data.

RESULTS

Our searches identified a total of 5,843 potentially eligible studies, of which 49 satisfied our inclusion criteria. Of these, three were suitable for pooled estimates of prevalence. The incidence rates for all-cause anaphylaxis ranged from 1.5 to 7.9 per 100,000 person-years. These data indicated that an estimated 0.3% (95% CI 0.1-0.5) of the population experience anaphylaxis at some point in their lives. Food, drugs, stinging insects, and latex were the most commonly identified triggers.

CONCLUSIONS

Anaphylaxis is a common problem, affecting an estimated 1 in 300 of the European population at some time in their lives. Future research needs to focus on better understanding of the trends across Europe and identifying those most likely to experience fatal reactions.

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.

The falling rate of positive penicillin skin tests from 1995 to 2007

BACKGROUND

Data on the rate of positive penicillin skin test (PenST) results over time in large populations are rare. The factors that influence positive PenST results are incompletely understood.

OBJECTIVES

We sought to correlate demographic variables to the rate of positive PenST results over time in a large group of patients with a history of penicillin allergy.

METHODS

RESULTS from the first test for all patients tested for penicillin allergy in the Kaiser Permanente Health Care Program in San Diego County, CA, between 1995 and 2007 are reported. All patients were tested with penicillin, penicilloyl-poly-lysine, penilloate, penicilloate, and amoxicillin.

RESULTS

There were 255 positive PenST results in 3469 individuals. The rate of positive PenST results declined from >10% to <5% during the 13 years studied. The positive PenST result rate could be accounted for by the year of testing (R(2) = 0.56; p = 0.003) without any significant contribution from the patient's age or the time since reaction (TSR). If the TSR was ≤13 years, the relative risk of a positive PenST result was 2.1 (95% confidence interval = 1.6-2.8). If the study subject's age was ≤38 years, the relative risk of a positive PenST result was 2.1 (95% confidence interval = 1.6-2.7). Females reported higher rates of penicillin allergy history than males did (11% compared with 6.6%; p < 0.0001), but there were no significant sex differences in the rate of positive PenST results.

CONCLUSIONS

There has been a steady decline in the proportion of positive PenST results between 1995 and 2007, independent of study subject age and TSR. Increasing age and increasing TSR were associated with a lower rate of positive PenST results.

Determining the negative predictive value of provocation tests with beta-lactams

BACKGROUND

The beta-lactam allergic work-up is mostly standardized. However, the negative predictive value of drug provocation tests is not yet well established.

METHOD

A historical-prospective multicentre cohort study was conducted in four centres (one in France, one in Portugal, two in Italy) to assess the negative predictive value of provocation tests with beta-lactams in patients initially tested for a suspicion of drug allergy/hypersensitivity. Patients were contacted at least 6 months after the work-up, between 2003 and 2007. A new allergic work-up was proposed to reacting patients.

RESULTS

Among the 457 patients included, 365 (79.9%) were followed up (159 [79.1%] from France, 153 [82.7%] from Italy and 53 [74.6%] from Portugal). Only 118 (25.8%) were re-exposed to the negatively tested beta-lactam. Nine (7.6%) reported a non-immediate (occurring more than 1 h after drug administration) reaction: five urticaria, three exanthema and one undefined cutaneous reaction. None were severe. Only four accepted a re-challenge, negative in two cases and positive in the two others. The negative predictive value was 94.1% (89.8-98.3) (111 out of 118 patients).

CONCLUSION

Although the negative predictive value of drug provocation tests may not be 100%, none of the false negative patients experienced a life-threatening reaction. This should reassure doctors who might hesitate to prescribe beta-lactams, even in patients with negative allergic work-ups.

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.

Delayed onset and protracted progression of anaphylaxis after omalizumab administration in patients with asthma

BACKGROUND

Risk of anaphylaxis is included in the prescribing information for omalizumab, but the nature of these reactions merits further elaboration.

OBJECTIVE

To describe cases of anaphylaxis associated with omalizumab administration in patients with asthma.

METHODS

We reviewed spontaneous postmarketing adverse event reports submitted to the US Food and Drug Administration's Adverse Event Reporting System database and to the manufacturers of omalizumab and cases published in the literature through December 2006. Diagnostic criteria for anaphylaxis outlined by the National Institute of Allergy and Infectious Diseases and the Food Allergy and Anaphylaxis Network were used to screen cases.

RESULTS

One-hundred twenty-four cases of anaphylaxis associated with omalizumab administration in patients with asthma were identified. Many cases had a delayed onset of symptoms beyond 2 hours after dose administration. Many cases were also characterized by a protracted progression, with individual signs and symptoms of anaphylaxis staggered over hours. Review of the case reports did not reveal any predictive risk factors for the delayed onset or protracted progression of anaphylaxis.

CONCLUSION

Omalizumab-induced anaphylaxis may be characterized by a delayed onset and a protracted progression of symptoms.

CLINICAL IMPLICATIONS

The unusual timing of anaphylaxis in these cases challenges our understanding of anaphylaxis. A delayed onset of symptoms and protracted progression of anaphylaxis should be taken into account when administering omalizumab.