Reproducibility of delayed-type reactions to betalactams

Is a Prolonged Drug Provocation Test Better Than a Single-Day Drug Provocation Test? A Systematic Review and Meta-Analysis

BACKGROUND

There is currently no standardized duration of drug provocation test (DPT) for confirming/delabeling beta-lactam hypersensitivity reaction (BL-HSR).

OBJECTIVES

This meta-analysis and systematic review aimed to investigate the added diagnostic value of extended-day over single-day DPT for confirming/delabeling BL-HSR in adults and children.

METHODS

The MEDLINE, EMBASE, Web of Science, and CINAHL online databases were searched from inception to March 15, 2023, for studies that performed extended-day DPT to confirm/delabel BL-HSR. Risk difference and risk ratio were used to compare the proportions of patients with confirmed BL-HSR by single-day or extended-day DPT.

RESULTS

A total of 10,371 DPTs from 42 studies were included. Extended-day DPTs ranged from 2 to 7 days, or as long as index reactions were reported (maximum 10 days). The overall prevalence of confirmed BL-HSR was 6.96% (3.31% during the first-day DPT, and 3.65% during extended-day DPT). Approximately half of the positive reactions during extended-day DPT occurred during the second/third day. The increased detected pool prevalence of confirmed BL-HSR yielded by extended-day DPT was 0.03 (95% CI, 0.02%-0.04%; I2 = 57.69%; P < .001), and the risk ratio of positive reactions between extended-day and single-day DPT was 1.94 (95% CI, 1.62-2.33; I2 = 36.26%; P < .001). The risk difference increased per 1% increase in prevalence of BL-HSR by 0.6% (95% CI, 0.4%-0.7%; P < .001). Twenty-three severe reactions occurred during DPT, and only 2 severe reactions (0.02%) occurred during extended-day DPT. An additional 28 extended-day DPTs were needed to identify 1 mild reaction.

CONCLUSIONS

The increased prevalence of confirmed BL-HSR observed during extended-day DPT could be attributed to the first-day DPT. As a result, our findings do not conclusively support the use of extended-day DPT over single-day DPT. Further studies, incorporating a washout period, are required to comprehensively compare these 2 approaches.

Frequency of severe reactions following penicillin drug provocation tests: A Bayesian meta-analysis

BACKGROUND

Patients with a penicillin allergy label tend to have worse clinical outcomes and increased healthcare use. Drug provocation tests (DPT) are the gold-standard in the diagnostic workup of penicillin allergy, but safety concerns may hinder their performance. We aimed to assess the frequency of severe reactions following a DPT in patients with reported allergy to penicillins or other β-lactams.

METHODS

We performed a systematic review, searching MEDLINE, Scopus, and Web of Science. We included primary studies assessing participants with a penicillin allergy label who underwent a DPT. We performed a Bayesian meta-analysis to estimate the pooled frequency of severe reactions to penicillin DPTs. Sources of heterogeneity were explored by subgroup and metaregression analyses.

RESULTS

We included 112 primary studies which included a total of 26,595 participants. The pooled frequency of severe reactions was estimated at 0.06% (95% credible interval [95% CrI] = 0.01%-0.13%; I2  = 57.9%). Most severe reactions (80/93; 86.0%) consisted of anaphylaxis. Compared to studies where the index reaction was immediate, we observed a lower frequency of severe reactions for studies assessing non-immediate index reactions (OR = 0.05; 95% CrI = 0-0.31). Patients reporting anaphylaxis as their index reaction were found to be at increased risk of developing severe reactions (OR = 13.5; 95% CrI = 7.7-21.5; I2  = 0.3%). Performance of direct DPTs in low-risk patients or testing with the suspected culprit drug were not associated with clinically relevant increased risk of severe reactions.

CONCLUSIONS

In patients with a penicillin allergy label, severe reactions resulting from DPTs are rare. Therefore, except for patients with potentially life-threatening index reactions or patients with positive skin tests-who were mostly not assessed in this analysis -, the safety of DPTs supports their performance in the diagnostic assessment of penicillin allergy.

Delabeling Delayed Drug Hypersensitivity: How Far Can You Safely Go?

Delayed immune-mediated adverse drug reactions (IM-ADRs) are defined as reactions occurring more than 6 hours after dosing. They include heterogeneous clinical phenotypes that are typically T-cell-mediated reactions with distinct mechanisms across a wide spectrum of severity from benign exanthems through to life-threatening cutaneous or organ-specific diseases. For mild reactions such as benign exanthem, considerations for delabeling are similar to immediate reactions and may include a graded or single-dose drug challenge with or without preceding skin or patch testing. Evaluation of challenging cases such as the patient who is on multiple drugs at the time a severe delayed IM-ADR occurs should prioritize clinical ascertainment of the most likely phenotype and implicated drug(s). Although not widely available and validated, procedures such as patch testing, delayed intradermal skin testing, and laboratory-based functional drug assays or genetic (human leukocyte antigen) testing may provide valuable information to further help risk stratify patients and identify the likely implicated and/or cross-reactive drug(s). The decision to use a drug challenge as a diagnostic or delabeling tool in a patient with a severe delayed IM-ADR should weigh the risk-benefit ratio, balancing the severity and priority for the treatment of the underlying, and the availability of alternative efficacious and safe treatments.

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 Closer Look at Penicillin Allergy History: Systematic Review and Meta-Analysis of Tolerance to Drug Challenge

BACKGROUND

True allergy to penicillin is rare, despite the high frequency with which it is reported. While most patients reporting penicillin allergy are not prone to anaphylaxis, it is not currently known what percentage of these patients will tolerate dose challenges of penicillin-based antibiotics. This review aims to determine the rate of tolerance in patients reporting penicillin allergy when challenged with penicillin-based antibiotics.

METHODS

We searched MedLine, Embase, and Cochrane Library for publications with English language translations between the years 2000 and 2017. We included randomized controlled trials, quasi-experimental, and observational studies of participants reporting penicillin allergy who received at least one systemic dose of a penicillin in the form of a drug challenge. At least 2 independent reviewers extracted data from included studies and assessed the quality of each included study. To generate primary outcome data, we calculated a summary estimate rate of penicillin tolerance from a pooled proportion of participants receiving penicillin with no adverse effects.

RESULTS

Initial literature search yielded 2945 studies, of which 23 studies were ultimately included in our review; 5056 study participants with reported history of penicillin allergy were challenged with a penicillin. After weighting for study sample size, a pooled average of 94.4% (95% confidence interval, 93.7%-95%) of participants tolerated the dose challenge without any adverse reaction.

CONCLUSION

Misrepresented penicillin allergy drives unnecessary use of alternative antibiotics, which may be less effective, more toxic, and more expensive than using penicillin. In addressing the problem of penicillin allergy over-diagnosis, evaluation should go beyond risk for type 1 hypersensitivity. Our data suggest that 94.4% of 5056 participants with reported penicillin allergy determined to be clinically appropriate for allergy evaluation tolerated repeat administration of penicillin-based antibiotics without any adverse reactions. This review generates meaningful information useful to clinical predictive analytics, in evaluating and managing patients with a reported history of penicillin allergy.

Provocation Tests in Nonimmediate Hypersensitivity Reactions to β-Lactam Antibiotics in Children: Are Extended Challenges Needed?

BACKGROUND

β-Lactam antibiotics are the most common trigger of reactions in children with most of them being nonimmediate (85.5%), but proven allergy after the allergological workup is between 7% and 10%. There is no agreement on how to perform the provocation tests in these types of hypersensitivity reactions.

OBJECTIVE

To determine whether or not repeated doses of the β-lactams are required to reproduce a nonimmediate reaction in children.

METHODS

This is a retrospective observational study. We included children under 14 years who were referred for a nonimmediate reaction to β-lactams. All patients underwent a 1-day hospital provocation and were kept under observation at home during the following days for at least the time elapsed between the first dose and the symptoms of the index reaction. If no reaction was triggered, the patient resumed the provocation at home with 2 daily therapeutic doses for an equal of interval time.

RESULTS

Ninety-seven patients were included in the study. A positive reaction was recorded in 14 of them (14.4%). The short hospital provocation triggered 3 immediate reactions and 8 delayed reactions. The home rechallenge developed 1 immediate reaction and 2 delayed reactions.

CONCLUSIONS

Nonimmediate reactions to β-lactams in children may be triggered with a 1-day provocation test. We suggest to perform a 1-day provocation test followed by an observational period of at least the time interval of the index reaction. If this challenge is negative, an extended home provocation could subsequently be carried out.

Old dog begging for new tricks: current practices and future directions in the diagnosis of delayed antimicrobial hypersensitivity

PURPOSE OF REVIEW

Antimicrobials are a leading cause of severe T cell-mediated adverse drug reactions (ADRs). The purpose of this review is to address the current understanding of antimicrobial cross-reactivity and the ready availability of and evidence for in-vitro, in-vivo, and ex-vivo diagnostics for T cell-mediated ADRs.

RECENT FINDINGS

Recent literature has evaluated the efficacy of traditional antibiotic allergy management, including patch testing, skin prick testing, intradermal testing, and oral challenge. Although patch and intradermal testing are specific for the diagnosis of immune-mediated ADRs, they suffer from drug-specific limitations in sensitivity. The use of ex-vivo diagnostics, especially enzyme-linked immunospot, has been highlighted as a promising new approach to assigning causality. Knowledge of true rates of antimicrobial cross-reactivity aids empirical antibiotic choice in the setting of previous immune-mediated ADRs.

SUMMARY

In an era of increasing antimicrobial resistance and use of broad-spectrum antimicrobial therapy, ensuring patients are assigned the correct 'allergy label' is essential. Re-exposure to implicated antimicrobials, especially in the setting of severe adverse cutaneous reaction, is associated with significant morbidity and mortality. The process through which an antibiotic label gets assigned, acted on and maintained is still imprecise. Predicting T cell-mediated ADRs via personalized approaches, including human leukocyte antigen-typing, may pave future pathways to safer antimicrobial prescribing guidelines.

Drug hypersensitivity in children: report from the pediatric task force of the EAACI Drug Allergy Interest Group

When questioned, about 10% of the parents report suspected hypersensitivity to at least one drug in their children. However, only a few of these reactions can be confirmed as allergic after a diagnostic workup. There is still a lack of knowledge on drug hypersensitivity (DH) epidemiology, clinical spectrum, and appropriate diagnostic methods particularly in children. Meanwhile, the tools used for DH management in adults are applied also for children. Whereas this appears generally acceptable, some aspects of DH and management differ with age. Most reactions in children are still attributed to betalactams. Some manifestations, such as nonsteroidal anti-inflammatory drug-associated angioedema and serum sickness-like reactions, are more frequent among young patients as compared to adults. Risk factors such as viral infections are particularly frequent in children, making the diagnosis challenging. The practicability and validity of skin test and other diagnostic procedures need further assessment in children. This study presents an up-to-date review on epidemiology, clinical spectrum, diagnostic tools, and current management of DH in children. A new general algorithm for the study of these reactions in children is proposed. Data are presented focusing on reported differences between pediatric and adult patients, also identifying unmet needs to be addressed in further research.

Drug provocation tests in hypersensitivity drug reactions

PURPOSE OF REVIEW

Drug provocation test (DPT) is necessary to diagnose most drug hypersensitivity reactions (HSRs) due to decreased sensitivity of skin testing even when combined with in-vitro tests in immunonologic drug HSR and limited availability of these tests in nonimmunologic reaction. We review the principles and controversial issues of DPT, and recent studies using DPT as a diagnostic tool.

RECENT FINDINGS

DPT is recommended in the diagnosis of HSR to β-lactams, as well as other drug classes [such as acetylsalicylic acid-NSAIDs (ASA-NSAIDs), non-β-lactams antibiotics, heparin, glucocorticoids, and local anesthetic agents]. In view of the decreased sensitivity of skin testing, limited accessibility to new benzylpenicillin polylysine (PPL)/mixture of minor determinant (MDM) test reagents and limited availability of validated sensitive in-vitro tests, individuals who require DPT to β-lactams are increasing. The negative predictive value of allergologic work-up is very high, ranging from 94 to 98% for β-lactams and those reactions after negative tests are mostly nonimmediate and mild. Finally, DPT is recommended to ascertain tolerability of alternative compound when evaluating cross-reactivity among different classes of β-lactams, NSAIDs and glucocorticoids, and possibly iodinated contrast media.

SUMMARY

DPT is often needed when evaluating patients with suspected drug HSR. More studies regarding standardization of the various protocols are needed in order to increase its acceptance and adoption as a standard practice in the diagnostic algorithm for drug HSR.