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

Comparison of two diagnostic criteria in the diagnosis of anaphylaxis in a tertiary adult allergy clinic

Background

Anaphylaxis is a very dynamic issue with its incidence and trigger profile changing over the years. We aimed to compile the characteristics of anaphylaxis cases diagnosed in our clinic prospectively and to make a comparison between diagnostic criteria proposed by National Institute of Allergy and Infectious Diseases/Food Allergy and Anaphylaxis Network (NIAID/FAAN) and World Allergy Organization (WAO).

Method

Three-item diagnostic criteria recommended by NIAID/FAAN (2006) were used in the diagnosis of anaphylaxis. The clinical features of the cases, risk factors, etiologies, severity of anaphylaxis, and treatment approach were determined. The same patients were also classified by current WAO diagnostic criteria.

Results

A total of 204 patients (158F/46 M, median age 45.3 years) were included. Drugs (65.2%), venom (9.8%) and food allergies (9.3%) were the top 3 etiologies. Among drug triggers, chemotherapeutics were the most common (17.7%), followed by antibiotics (15.3%) and non-steroidal anti-inflammatory drugs (14.2%). The patients were mostly diagnosed with the second criterion (84.8%), followed by the first criterion (11.8%) and the third criterion (3.4%) of the NIAID/FAAN criteria. In terms of WAO criteria, 82.8% of the patients were diagnosed with the first criterion, and 14.3% with the second criterion while 2.9% of the patients did not meet the WAO criteria. The severity of anaphylaxis was evaluated as grade-2, 3 and 4 in 30.9%, 64.2%, and 4.9% of the patients, respectively. Adrenaline was administered to 31.9% of the patients especially who had angioedema and bronchospasm (p = 0.04).

Conclusion

Our data suggest that covering more details in patient's history may prevent possible underdiagnosis and WAO diagnostic criteria seem to be insufficient in some patients. We believe that our results will contribute to the literature on anaphylaxis and would be groundwork for future studies.

Management of patients with suspected or confirmed antibiotic allergy. Executive summary of guidance from the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Allergy and Clinical Immunology (SEAIC), the Spanish Society of Hospital Pharmacy (SEFH) and the Spanish Society of Intensive Medicine and Coronary Care Units (SEMICYUC)

Suspected or confirmed antibiotic allergy is a frequently encountered clinical circumstance that influences antimicrobial prescribing and often leads to the avoidable use of less efficacious and/or more toxic or costly drugs than first-line antimicrobials. Optimizing antimicrobial therapy in patients with antibiotic allergy labels has become one of the priorities of antimicrobial stewardship programs (ASP) in several countries. This guidance document aims to make recommendations for the systematic approach to patients with suspected or confirmed antibiotic allergy based on current evidence. A panel of eleven members of involved Scientific Societies with expertise in the management of patients with suspected or confirmed antibiotic allergy formulated questions about the management of patients with suspected or confirmed antibiotic allergy. A systematic literature review was performed by a medical librarian. The questions were distributed among panel members who selected the most relevant references, summarized the evidence and formulated graded recommendations when possible. The answers to all questions were finally reviewed by all panel members. A systematic approach to patients with suspected or confirmed antibiotic allergy is recommended to improve antibiotic selection and, consequently clinical outcomes. A clinically oriented, 3-category risk-stratification strategy was recommended for patients with suspected antibiotic allergy. Complementary assessments should consider both clinical risk category and preferred antibiotic agent. Empirical therapy recommendations for the most relevant clinical syndromes in patients with suspected or confirmed β-lactam allergy were formulated. Recommendations on the implementation and monitoring of the impact of the guidelines were formulated. ASP and allergists should design and implement activities that facilitate the most adequate antibiotic use in these patients.

Quantifying exposure to chlorhexidine from decontamination of peripheral intravenous injection ports

BACKGROUND

Annually, almost 2 billion peripheral intravenous cannulas (PIVCs) are placed worldwide. In response to concerns of infectious complications, chlorhexidine is increasingly utilised for maintenance decontamination of PIVC injection ports. Concomitantly, the allergenic potential of chlorhexidine exposures has been highlighted by several case reports, implicating it as a trigger when used for this seemingly innocuous process. Given how widespread this application is, elucidating potential chlorhexidine exposure is needed to gauge its risks and benefits.

OBJECTIVE

To examine and quantify if chlorhexidine is entrained when used for PIVC injection port cleaning.

METHODS

Twenty benchtop PIVC set-ups were cleaned with 2% chlorhexidine and 70% alcohol wipes, following three different pragmatic protocols. Each set-up was injected with 10 ml ultrapure water, and samples tested by liquid chromatography-electrospray tandem mass spectrometry for entrained chlorhexidine.

RESULTS

Chlorhexidine was detected in every sample. Mean concentrations and standard deviations from each protocol were 41.47 ppb (4.08), 54.76 ppb (17.46), and 65.84 ppb (7.01). One-way ANOVA indicated a statistical difference between at least two groups (df = 2, F = 24.11, p < .00001), with Tukey's testing verifying significantly different mean concentrations between all groups (p < .01).

CONCLUSIONS

Using 2% chlorhexidine and 70% alcohol swabs to decontaminate PIVC injection ports resulted in consistent entrainment of chlorhexidine, with varying amounts correlated to how it was applied. These results validate case reports attributing anaphylactic/allergic reactions to suspected intravenous chlorhexidine entrainment and should factor into future risk-benefit assessments for its use in PIVC maintenance antisepsis policies and protocols.

Canada’s First Joint Oncology-Allergy Clinic: Successful Desensitization to Trastuzumab Following Severe Anaphylactic Reaction in Which Epinephrine Was Inappropriately Withheld

Background: Recognition of anaphylaxis and differentiation from other infusion reactions in an oncology setting is imperative; epinephrine is the recommended treatment for anaphylaxis and should be administered immediately to patients in whom anaphylaxis is suspected. Trastuzumab has a potentially tremendous oncological benefit, and when hypersensitivity reactions occur, rechallenge with desensitization protocols has become more common. Oncology presents a unique situation in which repeat drug exposure after a serious adverse reaction is often warranted due to the mortality risk of untreated cancer—allergists can assist with both symptom assessment and risk mitigation. Case presentation: This case showcases successful desensitization in a 43-year-old female with locally advanced HER2-positive breast cancer following a severe anaphylactic reaction to trastuzumab, in which epinephrine was not administered. We report the establishment of the Medical Oncology and Allergy Clinic: Canada’s first multidisciplinary clinic aimed at expediting the assessment and management of oncology patients with adverse drug reactions (including chemotherapy, contrast media, antimicrobials) and those with primary and acquired immunodeficiency. Conclusions: We propose this multidisciplinary clinic model as a treatment framework moving forward, with the goal of continuing first-line therapies in cancer patients who develop drug-hypersensitivity (i.e., through desensitization). This case highlights the unmet need for a multidisciplinary approach to the management of oncology patients who experience hypersensitivity reactions.

Comparative Effectiveness, Safety, and Real-World Outcomes of a Nurse-Led, Protocol-Driven Penicillin Allergy Evaluation From the Hong Kong Drug Allergy Delabelling Initiative (HK-DADI)

BACKGROUND

There is a high prevalence of unconfirmed penicillin allergy, which is associated with a multitude of adverse clinical outcomes. With the overwhelming burden of currently incorrect labels and the lack of allergy specialist services, new delabeling strategies are urgently needed.

OBJECTIVE

To assess the effectiveness, safety, and real-world outcomes of a nurse-led, protocol-driven evaluation of penicillin allergy, the Hong Kong Drug Allergy Delabelling Initiative (HK-DADI).

METHODS

Adult patients with suspected penicillin allergy were recruited into HK-DADI. Allergy and postdelabeling outcomes were retrospectively compared between patients evaluated via HK-DADI or traditional allergist evaluation.

RESULTS

A total of 312 completed penicillin allergy evaluation: 84 (27%) and 228 (73%) via HK-DADI and traditional pathways, respectively. Overall, 280 penicillin allergies were delabeled (90%). The delabeling rate between HK-DADI and traditional pathways was similar (90% vs 89%; P = .796). Among patients of the HK-DADI pathway, the delabeling rate was significantly higher among low-risk (LR) compared with non-LR patients (97% vs 77%; P = .010). Skin tests did not add diagnostic value among LR patients. No patients developed severe or systemic reactions during the evaluation. Upon 6- to 12-month follow-up (median, 10 months), 123 patients experienced infective episodes (44%) and 63 used penicillins again after delabeling (23%). This proportion was significantly higher in patients who were delabeled via HK-DADI compared with the traditional pathway (32% vs 19%; P = .026).

CONCLUSIONS

The Hong Kong Drug Allergy Delabelling Initiative, a nurse-led, protocol-driven evaluation, was safe and effective in penicillin allergy delabeling. It led to an even higher rate of future penicillin use after delabeling and mitigated the need for unnecessary skin testing among LR patients.

Basophil Activation Test Shows Poor Sensitivity in Immediate Amoxicillin Allergy

BACKGROUND

In light of the pandemic of spurious penicillin allergy, correct diagnosis of amoxicillin (AX) allergy is of great importance. The diagnosis of immediate hypersensitivity reactions relies on skin tests and specific IgE, and although reliable, these are not absolutely predictive. Therefore, drug challenges are needed in some cases, which contain the risk of severe reactions. Safe in vitro diagnostics as an alternative for the drug challenge in the diagnostic workup of AX allergy would be more than welcome to fill this gap. In this respect, the basophil activation test (BAT) has shown potential, but its clinical reliability is doubtful.

OBJECTIVE

To investigate the reliability of the BAT to AX and determining its exact place in the diagnostic algorithm of AX allergy.

METHODS

BAT for AX was performed in 70 exposed control individuals and 66 patients diagnosed according to the European Academy of Allergy and Clinical Immunology guidelines for AX allergy. Upregulation of both CD63 and CD203c was flow-cytometrically assessed.

RESULTS

Analyses revealed that 1370 μmol/L and 685 μmol/L were the most discriminative stimulation concentrations for CD63 and CD203c upregulation, respectively, and a diagnostic threshold of 9% for positivity for both markers was identified. At these concentrations, sensitivity and specificity for CD63 upregulation were 13% and 100%, respectively, and for CD203c upregulation, 23% and 98%.

CONCLUSIONS

BAT with dual analysis of CD63 and CD203c is of poor performance to document AX allergy. The sensitivity is too low to let it occupy a prominent role in the diagnostic algorithm.

Utility and Safety of Skin Tests in Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS): A Systematic Review

BACKGROUND

Determination of culprit drug in drug reaction with eosinophilia and systemic symptoms (DRESS) is crucial. Skin tests have been used, although it remains unclear how sensitive these are.

OBJECTIVE

To determine the value of skin tests in the assessment of drug causality in DRESS.

METHODS

A systematic literature search was conducted for publications from 1996 onward of skin tests (skin prick test = SPT, patch test = PT, intradermal test = IDT) performed in clearly defined DRESS cases. Outcomes of testing, drug culpability assessments, and challenge test data were extracted.

RESULTS

A total of 17 articles met inclusion criteria. In 290 patients with DRESS, patch testing was most frequent (PT = 97.2% [n = 282], IDT = 12.4% [n = 36], SPT = 3.1% [n = 9]). Positive results were noted in 58.4% (n = 160 of 282) of PTs, 66.5% of IDTs, and 25% of SPTs. When confidence of drug causality was high (n = 73 of 194), testing did not correlate well with clinical suspicion: PTs, 37.6%; IDTs, 36.5%. Direct comparison of skin testing with provocation testing (n = 12) showed 83.3% correlation. Positive IDT results were reported in 8 negative PT cases.

CONCLUSIONS

Skin tests, particularly PTs and IDTs, have been reported as tools for diagnosis of causal drugs in DRESS. Heterogeneity in methodology, results analysis, and reporting of cohorts make meta-analysis to determine sensitivity and specificity of published literature impossible and highlight weaknesses in the field. We propose that international collaboration is essential to harmonize the methodology and reporting measures from hypersensitivity testing studies in larger cohorts.

Allergic and other adverse reactions to drugs used in anesthesia and surgery

The list of drugs patients may be exposed to during the perioperative and postoperative periods is potentially extensive. It includes induction agents, neuromuscular blocking drugs (NMBDs), opioids, antibiotics, sugammadex, colloids, local anesthetics, polypeptides, antifibrinolytic agents, heparin and related anticoagulants, blue dyes, chlorhexidine, and a range of other agents depending on several factors related to individual patients’ clinical condition and progress in the postoperative recovery period. To avoid poor or ultrarapid metabolizers to a particular drug (for example tramadol and codeine) or possible adverse drug reactions (ADRs), some drugs may need to be avoided during or after surgery. This will be the case for patients with a history of anaphylaxis or other adverse events/intolerances to a known drug. Other drugs may be ceased for a period before surgery, e.g., anticoagulants that increase the chance of bleeding; diuretics for patients with acute renal failure; antihypertensives relative to kidney injury after major vascular surgery; and serotonergic drugs that together with some opioids may rarely induce serotonin toxicity. Studies of germline variations shown by genotyping and phenotyping to identify a predisposition of genetic factors to ADRs offer an increasingly important approach to individualize drug therapy. Studies of associations of human leukocyte antigen (HLA) genes with some serious delayed immune-mediated reactions are ongoing and variations of drug-metabolizing cytochrome CYP450 enzymes, P-glycoprotein, and catechol-O -methyltransferase show promise for the assessment of ADRs and non-responses to drugs, particularly opioids and other analgesics. Surveys of ADRs from an increasing number of institutions often cover small numbers of patients, are retrospective in nature, fail to clearly identify culprit drugs, and do not adequately distinguish immune-mediated from non-immune-mediated anaphylactoid reactions. From the many surveys undertaken, the large list of agents identified during and after anesthesia and surgery are examined for their ADR involvement. Drugs are classified into those most often involved, (NMBD and antibiotics); drugs that are becoming more frequently implicated, namely antibiotics (particularly teicoplanin), and blue dyes; those becoming less frequently involved; and drugs more rarely involved in perioperative, and postoperative adverse reactions but still important and necessary to keep in mind for the occasional potential sensitive patient. Clinicians should be aware of the similarities between drug-induced true allergic type I IgE/FcεRI- and pseudoallergic MRGPRX2-mediated ADRs, the clinical features of each, and their distinguishing characteristics. Procedures for identifying MRGPRX2 agonists and diagnosing and distinguishing pseudoallergic from allergic reaction mechanisms are discussed.

Beta-lactam hypersensitivity in children: Frequency and risk factors

AIMS

To determine the frequency of an authentic β-lactam (BL) hypersensitivity (HS) amongst a large number of children and to identify clinical risk factors that predict this hypersensitivity.

METHODS

All children with suspected BL allergy were evaluated by skin tests (ST) with the suspected BL. A 1-day oral provocation test (OPT) was performed in children with negative ST. We defined an authentic BL-HS case if the child exhibited a positive ST or a positive OPT. Risk factors associated with BL-HS were assessed using a univariate analysis. Covariates showing a P-value <.2 were included in the multivariate logistic regression analysis to determine independent predictors.

RESULTS

A total of 354 patients reporting 368 suspected BL reactions were included. The diagnosis of BL-HS was established in 24 children (6.7%). All these children had a positive ST. OPT was performed in 30 patients and was negative in all of them. In 110 children with a negative ST, BL was tolerated. In the risk factors analysis, 164 children were included. Older age (>5 years) at the reaction (odds ratio = 1.11; 95% confidence interval, 1.01-1.22; P = .02) and BL administered (odds ratio = 7.7; 95% confidence interval, 2.76-21.8; P < .001) were significantly associated with authentic BL-HS.

CONCLUSION

BL-HS should be evaluated with an appropriate allergy work-up before strict prohibition is made. In addition, age of patient and BL involved can be used as predictive factors of developing BL-HS in this population.

Beta-lactam hypersensitivity diagnosis in ambulatory and hospitalized settings require different approaches

BACKGROUND

Data on beta-lactam hypersensitivity (BLH) are mainly focused on immediate or mild nonimmediate reactions in the ambulatory setting, but limited in patients with concurrent illness and moderate-to-severe nonimmediate reactions in the hospitalized setting.

OBJECTIVE

To investigate the entire spectrum of BLH in Thai tertiary hospital.

METHODS

Clinical characteristics of 357 patients with suspected BLH were evaluated in a 7-year period. Culprit drug identification was performed in 335 patients by combined skin testing, in vitro testing, or drug provocation tests.

RESULTS

The predominant BLH presentations were non-immunoglobulin (Ig)E-mediated reactions with severe cutaneous adverse reactions of 18.9%, and BLH status was definitively confirmed in 18.1%. The most common verified culprits were cephalosporins (34.8%), particularly in hypersensitivity type IV reactions. Natural penicillins were the main implicated drugs in 48.5% of ambulatory patients. In contrast, cephalosporins and carbapenems were the main implicated drugs in hospitalized patients. Non-IgE-mediated anaphylaxis and serum sickness-like reaction remained diagnostically challenged. New generations of beta-lactams, hospitalized patients, recent allergic history, and underlying malignancies or autoimmune diseases were associated with increased BLH risk.

CONCLUSION

At present, cephalosporins are the leading causes of BLH, particularly in non-IgE-mediated reactions. More research on the verification of non-IgE hypersensitivity reactions from new generations of beta-lactams should be better emphasized.

CLINICAL TRIAL REGISTRATION

The registry was approved by the Ethics and Research Committee of the Faculty of Medicine, Chulalongkorn University, and listed on ClinicalTrials.gov (Identifier: NCT01667055; https://www.

CLINICALTRIALS

gov/ct2/show/NCT01667055).

Hypersensitivity reactions to biologics in children

INTRODUCTION

Hypersensitivity reactions (HSRs) have been observed with the use of biologics in children. The management of HSRs in children is mainly based on experiences from the adult population. Recently, data from different centers experienced in managing these reactions, including desensitization in children, have been published, allowing clinicians to have an appropriate global overview and compare results.

AREAS COVERED

This review highlights the published data on hypersensitivity reactions to biologics in children and drug desensitization protocols adapted to the pediatric population.

EXPERT OPINION

With regard to HSRs to biologics in children, few data are available. Compared with the adult population, there is a lack of knowledge in the endophenotypes, management and the standardization of protocols including premedication regimens in children. An international consensus is needed to provide clinicians with new insight on how to apply personalized management and to perform tailored desensitization protocols in pediatric populations. Various specialists including allergists, pediatricians, oncologists, hematologists, rheumatologists, and pharmacists, should build a multidisciplinary management team to keep pediatric patients on their best treatment options in the safest manner.

Diagnosing Single and Multiple Drug Hypersensitivity in Children: A Tertiary Care Center Retrospective Study

Drug hypersensitivity reactions (DHRs) are a type of adverse drug reactions with heterogeneous pathophysiological mechanisms and a broad spectrum of clinical manifestations. Since over-diagnosing is common in children, a complete allergy work-up is needed. A cross-sectional study was conducted at a tertiary care institution, covering the five-year period. Five hundred and four patients of both sexes, mean age 7.5 and with a medical history suggestive of DHR were evaluated. ENDA/EAACI guidelines were used for a diagnostic algorithm. Single drug hypersensitivity was registered in 375 patients and multiple drug hypersensitivity in 129. The main culprits in medical history were antibiotics (83%), non-steroidal anti-inflammatory drugs (NSAIDs) (8.4%) and analgoantipyretics (3.8%). Skin involvement was registered in 96.2%. DHRs were confirmed in 4.4% patients-six patients had positive skin tests and 13 had a positive drug provocation test. In the proven DHRs group, the main agents were antibiotics (72.7%), followed by NSAIDs (8.3%), and of all the skin manifestations, urticaria was most common (78.2%), followed by exanthema (10.5%) and angioedema (5.3%). Considering the above, anticipating DHRs and a proper referral of children to an allergologist is a key step in the assessment of drug hypersensitivity. A complete allergy work-up prevents unnecessary drug exclusion and allows most children to safely continue the use of first-line medications when needed.

Diagnostic Value of Oral Provocation Tests in Drug Hypersensitivity Reactions Induced by Nonsteroidal Anti-Inflammatory Drugs and Paracetamol

Oral drug provocation tests (DPT) are the basic diagnostic tool for the detection of hypersensitivity to non-opioid analgesics and for selecting a safe alternative for a patient. They are of great practical importance due to their common use, but the data on the follow-up of patients after negative DPT are still very scarce. We examined the further fate of 164 such adult patients after negative NSAID or paracetamol tests and analyzed which excipients in the studied drugs they could be exposed to after the diagnostic workup. A structured medical interview was performed 32.9 months (mean) after the provocation tests. Of the 164 patients, 131 (79.9%) retook the tested drug and 12 developed another hypersensitivity reaction, giving the estimated negative predictive value of 90.8%. These reactions were induced by acetylsalicylic acid, paracetamol, meloxicam, and diclofenac, and were clinically similar to the initial ones (most commonly urticaria and angioedema). There are 93 generics of these drugs on the local market, containing a total of 33 excipients for which hypersensitivity reactions have been reported. All available generics contain such excipients. Thirty-one patients (20.1%) did not take the previously tested drug again, most often because it was not needed or because they were afraid of another reaction. DPT with analgesics has a high diagnostic performance. A minority of patients had relapsed after reexposure. One of the underestimated reasons for this may be drug excipients provoking a reaction, so it is advisable to use exactly the same medical product that has been negatively tested. Many patients avoid reexposure to a given drug, despite negative tests, therefore very reliable patient education in connection with DPT is highly needed.

Drug allergy evaluation in children with suspected mild antibiotic allergy

Background

Adverse antibiotic reactions caused by an immunological mechanism are known as allergic reactions. The percentage of reported antibiotic allergies is likely to differ from the one validated after a drug provocation test (DPT) with the culprit antibiotic. This study aimed to compare the percentage of children who were thought to be allergic to a certain antibiotic with those who have a true allergy, as confirmed by DPTs. We also validated Skin Prick Tests (SPTs) and Intradermal Tests (IDTs) by assessing their sensitivity and specificity, in diagnosing antibiotic allergies using DPT as the gold standard. Furthermore, we investigated epidemiological risk factors such as personal and family history of atopic disease and eosinophilia.

Methods

Children with a history of possible allergic reaction to an antibiotic underwent a diagnostic procedure that included: (1) Eosinophil blood count, (2) SPTs, (3) IDTs and (4) DPTs. The parameters were compared with Pearson's Chi-Square and Fisher's Exact Test. Several risk factors that were found significant in univariate analysis, such as personal and family history of atopic disease, and positive SPTs and IDTs were examined with multiple logistic regression analysis to see if they were related to a higher risk for a positive DPT.

Results

Semi-synthetic penicillin was the most common group of antibiotics thought to cause allergic reactions in this study. Overall, 123 children with a personal history of an adverse reaction to a certain antibiotic, were evaluated. In 87.8% of the cases, the symptoms had occurred several hours after administration of the culprit antibiotic. Both SPTs and IDTs had low sensitivity but high specificity. Moreover, they had a high positive predictive value (PPV). In contrast, eosinophilia was not recognized as a risk factor. Seventeen patients (13.8%) had a true antibiotic allergy, as confirmed by a positive DPT. A positive IDT was a strong predictor of a positive DPT, along with a positive personal and family history of atopy.

Conclusion

SPTs and IDTs are very reliable in confirming antibiotic allergy when found positive. A negative result of a SPT highly predicts a negative DPT. A positive IDT and a positive personal and family history of atopy were recognized as significant risk factors for antibiotic allergy.

Skin Testing and Drug Provocation Tests in Epidermal Necrolysis: A French Experience

BACKGROUND

There are limited data on the use of skin testing, other than patch testing, and challenges in the evaluation of epidermal necrolysis (EN), including Stevens-Johnson syndrome and toxic epidermal necrolysis.

OBJECTIVE

To report a French multicenter experience in skin testing and challenges in EN, and investigate the factors associated with tests' positivity.

METHODS

All patients who were evaluated by patch tests (PTs), skin prick tests, intradermal tests (IDTs), or drug provocation tests (DPTs) for EN between 2010 and 2020 were retrospectively included through 2 French drug reaction networks.

RESULTS

In total, 113 patients were included from 8 centers. Median (interquartile range) time from EN to hypersensitivity workup was 7.9 months (5.1-15 months). All patients had PTs, 17 (15%) had skin prick tests or IDTs with delayed readings and 32 (28.3%) had DPTs. One mild reaction occurred after a DPT. Overall, 22 patients (19.5%) had positive PTs, and the only factors associated with positivity were Algorithm of Drug Causality for Epidermal Necrolysis (ALDEN) score and drug class. Only 1 IDT was positive but considered irrelevant. The DPTs were never performed to prove responsibility of a highly suspected drug but were used to confirm current tolerance of needed medications.

CONCLUSIONS

Allergological workup in EN, performed by specialists involved in EN, seems safe. Skin tests, although of limited sensitivity, can be helpful for considering the reintroduction of essential drugs according to a benefit-to-risk decision. We propose an algorithm for approaching hypersensitivity testing in patients with EN, to be adapted to each patient.

The Combined Use of Chronological and Morphological Criteria in the Evaluation of Immediate Penicillin Reactions: Evidence From a Large Study

BACKGROUND

Immediate hypersensitivity reactions to penicillins are often labeled on the basis of a similar set of symptoms, but a key feature of these reactions that can be reproduced in diagnostic testing may be the timing of a reaction in relation to the dose administration.

OBJECTIVE

To determine whether the timing of a reaction in response to the last dose of a penicillin would predict the results of diagnostic testing.

METHODS

We evaluated 1074 patients by performing skin tests, serum specific IgE assays (ImmunoCAP), and challenges. Patients who were evaluated by us more than 6 months after their reactions and found negative were reevaluated within 2 to 4 weeks.

RESULTS

Patients who had reacted within 1 hour after the first dose, within 1 hour after subsequent doses, more than 1 hour to within 6 hours after the first dose, or more than 1 hour to within 6 hours after subsequent doses were classified as group A (758 individuals), B (92), C (67), or D (157), respectively. Penicillin hypersensitivity was diagnosed in 707 patients (65.8%) by skin tests (407 patients, 57.6%), ImmunoCAP (47, 6.6%), both tests (232, 32.8%), or challenges (21, 3%). A conversion to allergy-test positivity occurred in 7 of 10 patients with anaphylactic reactions and in 1 of 28 patients with other reactions who were reevaluated after negative challenges. The rate of penicillin-allergic patients in groups A, B, C, and D was 85%, 35.9%, 35.8%, and 3.8%, respectively. Only 1 of 107 patients reporting cutaneous reactions lasting more than 1 day had positive results to allergy tests.

CONCLUSIONS

IgE-mediated hypersensitivity can be diagnosed by skin tests in about 70% of subjects who react within 1 hour (eg, patients from groups A and B). This hypersensitivity can be lost over time, as demonstrated by the negativization of allergy tests in follow-up studies. In subjects with anaphylactic reactions, however, it is advisable to not consider this phenomenon definitive. In fact, a conversion to allergy test positivity can be observed in up to 20% of such subjects retested after negative challenges.

Dietary parameters in patients with drug allergy: Assessing dietary inflammatory index

Background

Research on the increasing incidence of allergic diseases evidenced the role of diet as a potential key factor. Diet can modulate the low-grade systemic inflammation related to obesity and several diseases. There are no published data on drug allergy.

Aim

To investigate a potential association between diet, including dietary inflammatory index (DII), and drug allergy. Also, to evaluate correlations between diet and obesity, inflammatory and metabolic parameters in patients with drug allergy.

Methods

Ninety consecutive patients studied for suspected drug allergy were evaluated in terms of dietary parameters, anthropometric measurements, bioimpedance and biochemical analysis. DII was calculated based on information collected from a food frequency questionnaire.

Results

After diagnostic work-up, 39 patients had confirmed drug allergy and 45 excluded, representing the study group and the control group, respectively. The majority (79%) were female, with mean age of 39.58±13.3 years. The 84 subjects revealed an anti-inflammatory diet pattern. No significative difference was found in DII scores between drug allergic patients and controls (-3.37±0.95 vs -3.39±0.86, p = 0.985). However, the patients with drug allergy revealed higher obesity and inflammatory parameters. A significative negative correlation was found between DII and adiponectin levels, in the control group (r = -0.311, p = 0.040). In the patient group, a significative positive correlation was observed between DII and triglycerides (r = 0.359, p = 0.032). No other correlations were found between DII and the assessed parameters. Patients with drug allergy presented a significative higher intake of mono-unsaturated fatty-acids comparing to controls (19.8±3.7 vs 17.8 ± 4.0, p = 0.021). No other statistically significant differences were achieved in dietary parameters, between patients and controls.

Conclusion

The population assessed in this study revealed an anti-inflammatory diet profile. Although we have found in a previous work that the same patients with drug allergy revealed higher obesity and inflammatory parameters, the DII did not allow to distinguish between patients with drug allergy or controls. The DII scores correlated with triglycerides levels in the drug allergy patients and inversely with adiponectin levels in the control group. Larger studies are needed to clarify the potential role of the diet in drug allergy and its outcomes.

Antibiotic allergy in children with cystic fibrosis: A retrospective case-control study

Antibiotic allergy is a big problem that may affect the treatment and life quality of patients with cystic fibrosis (CF).

AIM

To evaluate predictive factors for confirmed antibiotic hypersensitivity in children with CF.

METHODS

In this case-controlled study, we examined 15 patients with CF who had been confirmed with antibiotic allergy. Additionally, we included a control group of age- and gender-matched 45 CF patients with no antibiotic allergy. The diagnosis of antibiotic allergy was confirmed in the presence of a compatible history and a positive response in the drug skin test or provocation test. Multiple drug hypersensitivity was classified according to the temporal relationship of antibiotics: (i) distant, (ii) simultaneous, and (iii) sequential. The data were analyzed by conditional logistic regression.

RESULTS

β-lactam allergy was confirmed in eight patients (ceftazidime n = 5, piperacillin-tazobactam n = 3) and non-β-lactam allergy was confirmed in two patients (ciprofloxacin n = 1, azithromycin n = 1). Additionally, multiple drug hypersensitivity in five patients (distant n = 4, sequential n = 1), among whom two patients showed hypersensitivity against ceftazidime/piperacillin-tazobactam+ ciprofloxacin/levofloxacin, two patients showed hypersensitivity against ceftazidime+ ciprofloxacin n = 2, and one patient showed hypersensitivity against piperacillin-tazobactam+ amikacin+ trimethoprim-sulfamethoxazole. All patients (n = 13) with confirmed β-lactam allergy were meropenem tolerant. Multivariate analysis indicated that immediate reactions (, p &lt; 0.001) and allergic evaluation in the first six months after the reaction (p = 0.036) were significant risk factors for the prediction of antibiotic hypersensitivity.

CONCLUSION

Beta-lactam antibiotic allergy is the most commonly confirmed drug allergy in children with CF. However, unlike normal children, ceftazidime and piperacillin-tazobactam account for the majority.

Delayed-Type Heparin Allergy: Intravenous Tolerance Despite Inflammatory Skin Reaction After Subcutaneous Injection

BACKGROUND

Heparin allergy most frequently manifests as delayed-type hypersensitivity (DTH) causing an itchy inflammatory skin reaction at the site of subcutaneous injection. An important differential diagnosis is circumscribed skin necrosis due to heparin-induced thrombocytopenia.

OBJECTIVES

An inflammatory skin reaction to subcutaneously injected heparin generally entails the quest for alternative anticoagulation; concerns may particularly arise in an emergency situation requiring intravenous heparin administration.

METHODS

All heparin DTH cases seen in our department over the last 17 years underwent standardized allergy diagnostics including challenge testing, that is, subcutaneous injection of fondaparinux and intravenous administration of unfractionated heparin (UFH).

RESULTS

Of a total of 50 patients with confirmed heparin allergy, DTH was found in 48 (96.0%), and immediate-type, presumably IgE-mediated hypersensitivity was diagnosed in only 2 (4.0%). In the 48 DTH cases, intradermal testing revealed broad cross-reactivity between UFH and low-molecular-weight heparins (LMWH) including nadroparin, dalteparin, and enoxaparin. Cross-reactivity with (or concomitant sensitization to) fondaparinux was seen in only 3 (6.3%) cases. Intravenous administration of UFH was tolerated by all 45 patients challenged, despite DTH to UFH and LMWH as demonstrated by intradermal testing.

CONCLUSIONS

If an inflammatory skin reaction at the site of subcutaneously injected heparin is observed or reported without any evidence of skin necrosis or thrombocytopenia, intravenous administration of UFH seems to be sufficiently safe and may be considered without allergy testing if urgently indicated in an emergency situation. Fondaparinux is the most suitable alternative for subcutaneous application.

Tools to improve the diagnosis and management of T-cell mediated adverse drug reactions

Delayed drug T-cell immune-mediated hypersensitivity reactions have a large clinical heterogeneity varying from mild maculopapular exanthema (MPE) to severe cutaneous adverse reactions (SCARs) such as acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS) and severe skin necrosis and blistering as seen in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Given the knowledge gaps related to the immunopathogenesis of these conditions, the absence of validated diagnostic tools and the significant associated morbidity and mortality, patients with SCARs often have limited drug choices. We performed a comprehensive review aiming to evaluate in vivo diagnostic tools such as delayed intradermal skin and patch testing and ex vivo/in vitro research assays such as the lymphocyte transformation test (LTT) and the enzyme-linked ImmunoSpot (ELISpot) assay. We searched through PubMed using the terms “drug allergy,” “in vivo” and “ex vivo” for original papers in the last 10 years. A detailed meticulous approach adapted to the various clinical phenotypes is recommended for the diagnostic and management of delayed drug hypersensitivity reactions. This review highlights the current diagnostic tools for the delayed drug hypersensitivity phenotypes.

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.

Agreement of a clinical scoring system with allergic anaphylaxis in suspected perioperative hypersensitivity reactions: prospective validation of a new tool

BACKGROUND

A clinical scoring system to estimate the likelihood that a reaction represents a perioperative immediate hypersensitivity reaction has been devised using a Delphi consensus process. Agreement of this clinical scoring system with the outcome of allergological assessment would allow the use of this tool in post-resuscitation and subsequent management of suspected perioperative immediate hypersensitivity reaction and potentially as a new standard reference for clinical investigations.

METHODS

We prospectively scored 301 cases of suspected perioperative immediate hypersensitivity reaction according to the Hypersensitivity Clinical Scoring Scheme. Classification of cases was by allergological workup based on immediate and delayed investigations. The discrimination and calibration of the Hypersensitivity Clinical Scoring Scheme was compared with results from an expert panel of allergologists, skin testing, mast cell tryptase ratios, and specific IgE assays, as was agreement by Cohen's kappa coefficient.

RESULTS

The Hypersensitivity Clinical Scoring Scheme predicted cases of allergic perioperative immediate hypersensitivity reaction with comparable discrimination to an expert panel, mast cell tryptase formula, and specific IgE assays in anaphylaxis to neuromuscular blocking drugs. Using a score threshold of 15 or greater to indicate allergic perioperative immediate hypersensitivity reaction, the sensitivity was 88.9%, with a specificity of 79.4%. Prospectively, the Hypersensitivity Clinical Scoring Scheme correctly classified a greater number of subjects than the expert panel and the optimal post hoc binary logistic regression model (86% vs 85% vs 84%), however it was inferior to skin testing.

CONCLUSION

The Hypersensitivity Clinical Scoring Scheme predicts allergic perioperative immediate hypersensitivity using features of the acute syndrome. This approach could guide algorithms for the post-resuscitative management of suspected perioperative immediate hypersensitivity, and identify patients requiring drug provocation challenge.

NSAID Hypersensitivity in the Pediatric Population: Classification and Diagnostic Strategies

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently administered drugs, mainly for their anti-pyretic, but also for pain-relieving and anti-inflammatory effects in children. NSAIDs are composed of structurally divergent subgroups of drugs with similar pharmacological and adverse effects. Aspirin originates from salicin and was the first synthesized analgesic. As a prototype of NSAIDs; aspirin-induced hypersensitivity reactions were first reported, but subsequently, other phenotypes of hypersensitivity reactions were also described with aspirin and other NSAIDs. There are certain challenging aspects of NSAID-hypersensitivity in the pediatric population that need to be further investigated. These include the effect of age on drug metabolism and the natural history of the various phenotypes of NSAID-hypersensitivity, the effect of certain co-factors (infections, exercise) on NSAID-hypersensitivity, and diagnostic clinical and laboratory biomarkers clarifying the endotypes. In recent years, a non-negligible number of case series, studies and expert panel reports have been published in this field with some novel features and diagnostic modalities in the pediatric population. With the current review; the clinical phenotypes and diagnostic and management modalities of suspected NSAID-induced hypersensitivity reactions in childhood and adolescence were explained and updated by examining past and current publications.

Antibiotic Allergy De-Labeling: A Pathway against Antibiotic Resistance

Antibiotics are one of the most frequently prescribed drugs. Unfortunately, they also are the most common cause for self-reported drug allergy, limiting the use of effective therapies. However, evidence shows that more than 90% of patients labeled as allergic to antibiotics are not allergic. Importantly, the label of antibiotic allergy, whether real or not, constitutes a major public health problem as it directly impacts antimicrobial stewardship: it has been associated with broad-spectrum antibiotic use, often resulting in the emergence of bacterial resistance. Therefore, an accurate diagnosis is crucial for de-labeling patients who claim to be allergic but are not really allergic. This review presents allergy methods for achieving successful antibiotic allergy de-labeling. Patient clinical history is often inaccurately reported, thus not being able to de-label most patients. In vitro testing offers a complementary approach but it shows limitations. Immunoassay for quantifying specific IgE is the most used one, although it gives low sensitivity and is limited to few betalactams. Basophil activation test is not validated and not available in all centers. Therefore, true de-labeling still relies on in vivo tests including drug provocation and/or skin tests, which are not risk-exempt and require specialized healthcare professionals for results interpretation and patient management. Moreover, differences on the pattern of antibiotic consumption cause differences in the diagnostic approach among different countries. A multidisciplinary approach is recommended to reduce the risks associated with the reported penicillin allergy label.

Characterization, epidemiology and risk factors of multiple drug allergy syndrome and multiple drug intolerance syndrome: A systematic review

Background

Multiple drug allergy and multiple drug intolerance syndrome (MDAS/MDIS) labels are an impediment to clinical care and knowledge regarding these conditions is limited. This systematic review investigated the characterization, epidemiology, risk factors, clinical impact and pharmaco-economics of MDAS and MDIS.

Methods

Systematic literature search across 11 databases (01 January 2000-06 November 2020) for MDIS, MDAS and related terminology. Studies were reviewed for quality of evidence and risk of bias by employing Critical Appraisal Skills Programme cohort study checklist. A narrative synthesis approach facilitated by systematic textual descriptions, tabulation and thematic analysis was adopted.

Results

There was heterogeneity in terminology and methodology. Few studies applied standard drug allergy diagnostic methods. There is some evidence to suggest that multiple drug hypersensitivity syndrome (MDHS; i.e., confirmed allergies in MDAS) is a distinct clinical entity. Prevalence of MDIS and MDAS labels in unselected & selected populations varied between 2.1%-6.4% & 4.9%-90% and 1.2% & 0%-36% respectively. Reported risk factors included female gender, increasing age, body mass index, anxiety, depression, co-morbidities, concurrent allergies and increased healthcare utilization. Drugs commonly implicated were antibiotics and non-steroidal anti-inflammatory drugs. No studies relating to clinical impact and pharmaco-economics were found.

Conclusion

There is considerable burden of MDAS and MDIS labels. Data needs cautious interpretation as majority of studies described involved unverified labels. Despite this limitation and heterogeneity of studies, there is some evidence to suggest that MDHS is a distinct clinical entity. Well-designed multi-centre studies applying standardized terminology and diagnostic methodology are needed to gain further insight into these conditions.

Standardized testing and written communication improve patient understanding of beta-lactam allergy testing outcomes: A multicenter, prospective study

Background

Historical penicillin allergy is commonly reported, but the lack of standardized allergy clinic practices may diminish the ability to delabel beta-lactam allergy appropriately.

Objective

We sought to improve beta-lactam allergy testing and patient understanding of their antibiotic allergy status by standardizing testing and communication practices between 7 adult and pediatric hospital centers.

Methods

Phase 1 prospectively described the beta-lactam allergy testing practices at each center. Following this, practice was standardized to achieve a defined panel of skin testing reagents, pro forma result letters for patients and referring doctors, and provision of medical alert jewelry to those with confirmed allergy. Testing outcomes and patient perception regarding allergy status 8 weeks postassessment were compared before (phase 1) and after standardization (phase 2). Primary outcomes were the percentage of participants delabeled after testing, and concordance rates between participant perception of their allergy status and their status as determined by the treating physician at 8-week follow-up.

Results

Of 195 adult and pediatric participants (median age, 50 years; 21.5% <18 years; 36.9% males), 75% were delabeled of their beta-lactam allergy. No patient experienced anaphylaxis related to any beta-lactam delabeling testing. In phase 1, 75% of participants received written results, 52% were informed verbally, and 48% received results in more than 1 form. All phase 2 participants received written results (P < .01), 61% received verbal results from a physician as well (P > .05). At 8-week follow-up, 54% of phase 1 participants had concordant perceptions of their allergy status as the testing team versus 91.6% in phase2 (P < .001). Of the 17 participants who were delabeled and treated with a beta-lactam antibiotic during the 8-week follow-up period, there were no reported allergic reactions, although 1 participant experienced anaphylaxis following exposure to amoxicillin-clavulanic acid 1 year after delabeling.

Conclusions

Standardization of testing and written patient information improved short-term patient perception of beta-lactam allergy status.

Amoxicillin hypersensitivity: patient outcomes in a seven-year retrospective study

BACKGROUND

The beta-lactam antibiotic amoxicillin and the beta-lactamase inhibitor clavulanic acid in combination with amoxicillin are known to both cause immediate and non-immediate type hypersensitivity.

OBJECTIVE

To characterize a large cohort of patients with a history of amoxicillin or amoxicillin-clavulanic acid hypersensitivity.

METHODS

Retrospective analysis of demographics, presentation, investigation, and management of 331 patients presenting to one allergy center with a history of hypersensitivity to amoxicillin or amoxicillin-clavulanic acid.

RESULTS

Hypersensitivity was confirmed in 37/221 (17%) patients who took amoxicillin and 47/110 (43%) patients who took amoxicillin-clavulanic acid as the index drug. In immediate hypersensitivity, skin testing confirmed the diagnosis in 66/139 (47%) patients. Penicillin cross-reactivity was observed in 16/36 (44%). 13/16 (81%) cross-reactive patients reacted to amoxicillin-clavulanic acid as the index drug. All skin test negative patients (73/139) underwent drug provocation. The negative predictive value of skin tests was 89%. In non-immediate hypersensitivity, delayed intradermal tests confirmed diagnosis in 12/170 (7%). 8/12 (67%) skin test positive patients presented with DRESS. All skin test negative patients (158/170) underwent drug provocation. The negative predictive value of skin tests was 95%. Penicillin cross-reactivity was observed in 3/12 (25%). Ten patients were diagnosed with hypersensitivity to clavulanic acid.

CONCLUSION

The negative predictive value of skin tests in both immediate and non-immediate hypersensitivity reactions is excellent and excludes severe allergy. Non-immediate hypersensitivity is rare. Confirmed hypersensitivity is more likely if amoxicillin-clavulanic acid is the index drug. Cross-reactivity was more common in patients presenting with immediate hypersensitivity, most commonly involving benzylpenicillin. A minority of patients were allergic to clavulanic acid.

Hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: does age matter?

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are reported to be the leading cause of drug hypersensitivity reactions. The aim of this study was to characterize a cohort of patients with NSAID hypersensitivity and establish if there are any differences between two groups of adult patients, under 55 years old and over 55 years old, and identify safe alternative options. Methods: Patients with NSAID hypersensitivity who were referred to a single tertiary Allergy center from January 2019 to December 2021 were included. Clinical information was obtained from a review of medical records. Results: A total of 135 patients with a history of NSAID-induced hypersensitivity reactions were included, 80 patients under 55 years old and 55 patients older than 55. Most of the patients enrolled were female (80.74%) and the mean age was 50.21 years, ranging from 18 to 78 years old. The time interval between the first reaction and the allergy work-up was longer in the older group (average timeframe 6.87 years) than in the younger group (average timeframe 3.77 years). The main culprit was metamizole in both groups. An oral provocation test to paracetamol was performed in most of the patients who tolerated the intake of 1000 mg, except for 2 patients who developed angioedema. Conclusion: Angioedema was the most encountered symptom in our population. Age does not influence the allergy work-up of patients with a history of NSAID-induced hypersensitivity reactions. The drug provocation challenge remains the gold standard for finding a suitable alternative in patients with NSAID-induced hypersensitivity.

Changes in Sensitization Patterns in the Last 25 Years in 619 Patients with Confirmed Diagnoses of Immediate Hypersensitivity Reactions to Beta-Lactams

Beta-lactam (BL) drugs are the antibiotics most prescribed worldwide due to their broad spectrum of action. They are also the most frequently implied in hypersensitivity reactions with a known specific immunological mechanism. Since the commercialization of benzylpenicillin, allergic reactions have been described; over the years, other new BL drugs provided alternative treatments to penicillin, and amoxicillin is now the most prescribed BL in Europe. Diagnosis of BL allergy is mainly based on skin tests and drug provocation tests, defining different sensitization patterns or phenotypes. In this study, we evaluated 619 patients with a confirmed diagnosis of BL-immediate allergy during the last 25 years, using the same diagnostic procedures with minor adaptations to the successive guidelines. The initial eliciting drug was benzylpenicillin, which changed to amoxicillin with or without clavulanic acid and cephalosporins in recent years. In skin tests, we found a decrease in sensitivity to major and minor penicillin determinants and an increase in sensitivity to amoxicillin and others; this might reflect that the changes in prescription could have influenced the sensitization patterns, thus increasing the incidence of specific reactions to side-chain selective reactions.

DRESS characteristics according to the causative medication

BACKGROUND

To date, no study has identified a clear relationship between drug and a specific clinical presentation of DRESS.

OBJECTIVES

To investigate the particularities of DRESS and analyze the variation of DRESS pattern according to culprit drugs.

METHODS

We analyzed cases of DRESS notified to the Department of Clinical Pharmacology at the University Hospital of Monastir over a 15-year period. The statistical study was performed using the comparative and multivariate analysis.

RESULTS

DRESS was mostly induced by anticonvulsive agents (27%) followed by allopurinol (26.3%) and antibiotics (24%): For anticonvulsive agents, the occurrence of lymphadenopathy was higher, renal involvement was rare and mild, and positive skin tests were more frequent. The allopurinol group was associated with the patient's older age and a lower incidence of lymphadenopathy and kidney injury. For antibiotics, eosinophilia rate was lower, time to recovery was shorter, and RegiSCAR score was low. The multivariate analysis showed a link of allopurinol with severe renal impairment, antibiotics with short latency period and low RegiSCAR score, and anticonvulsants with high propensity of positive skin test.

CONCLUSION

We report the largest African and south Mediterranean cohort of DRESS and evaluated the usefulness of skin tests in identifying the culprit drug. The prominent finding was that latency period and renal involvement may independently differ according to culprit drugs.

Psychological Distress and Drug Provocation Test-Related Anxiety Levels of Pediatric Patients and Their Parents

Background: Drug provocation tests (DPTs) are the gold standard for the diagnosis of drug hypersensitivity reaction (DHR). To the best of our knowledge, there is no previous study reporting DPT-related anxiety levels in children and their parents. This study aimed to determine the difference in pre- and post-DPT anxiety levels of parents and children who were informed of the possibility of another DHR during the DPT, and to evaluate the relationship between parental psychological distress and anxiety levels. Methods: The study included children who underwent DPT in our clinic between July 1, 2019, and February 29, 2020, and accompanying parents who consented to participate. Age-appropriate State-Trait Anxiety Inventory scales were used to assess levels of state and trait anxiety in the patients and parents. The Symptom Checklist-90-Revised (SCL-90-R) was used to screen for psychological symptoms in parents. Results: Data were collected from the parents of 69 children who underwent DPTs. The patients' median age was 7.28 (interquartile range: 4.52-10.06) and their parents' mean age was 35.28 ± 5.38 years. Anxiety-related data were collected from 21 pediatric patients. The children and parents had higher state anxiety scores before DPT compared to after DPT. There was a positive correlation between the parents' trait anxiety and pre-DPT state anxiety scores. In addition, parental pre-DPT state anxiety scores were positively correlated with SCL-90-R general severity index, somatization, anxiety, obsessive-compulsive, and depression subscale scores. Conclusion: The risk of allergic reaction in DPT may cause anxiety. A high level of parental anxiety before DPT, which gradually decreased after negative test results, was associated with history of drug-induced anaphylaxis in their children and high trait anxiety. Appropriate evaluation of patients and parents before DPT and providing detailed information may be important to reduce this anxiety.

Immediate Hypersensitivity Reactions Induced by COVID-19 Vaccines: Current Trends, Potential Mechanisms and Prevention Strategies

As the world deals with the COVID-19 pandemic, vaccination remains vital to successfully end this crisis. However, COVID-19-vaccine-induced immediate hypersensitivity reactions presenting with potentially life-threatening systemic anaphylactic reactions are one of the reasons for vaccine hesitancy. Recent studies have suggested that different mechanisms, including IgE-mediated and non-IgE-mediated mast cell activation, may be involved in immediate hypersensitivity. The main culprits triggering hypersensitivity reactions have been suggested to be the excipients of vaccines, including polyethylene glycol and polysorbate 80. Patients with a history of allergic reactions to drugs, foods, or other vaccines may have an increased risk of hypersensitivity reactions to COVID-19 vaccines. Various strategies have been suggested to prevent hypersensitivity reactions, including performing skin tests or in vitro tests before vaccination, administering different vaccines for the primary and following boosters, changing the fractionated doses, or pretreating the anti-IgE antibody. This review discusses the current trends, potential mechanisms, and prevention strategies for COVID-19-vaccine-induced immediate hypersensitivity reactions.

Localized and Generalized Skin Adverse Drug Reactions to Nadroparin Calcium Injection in 6 Cases of Pregnant Women

Background

Despite the increasing number of skin adverse drug reactions caused by nadroparin calcium have been reported, mostly, little is known regarding of their details of clinical characteristics, especially for generalized skin adverse drug reactions. We sought to evaluate localized and generalized characteristics of the skin adverse drug reaction to nadroparin calcium injection in pregnant women.

Methods

A retrospective study was conducted on 6 pregnant women, who experienced localized and generalized skin adverse drug reactions during long-term nadroparin calcium injection. The patients' clinical and imaging information were retrieved from medical records. The skin prick test, patch test, and intradermal test were performed after they stopped lactation. Causality assessment of suspected adverse drug reactions was performed on these cases.

Results

The average total dose of nadroparin calcium injection in the 6 cases was 64.17 ± 22.66. Localized skin adverse drug reaction, manifested as erythema at the injection point, appeared after 47.5 ± 17.4 days of subcutaneous injection of nadroparin calcium. Generalized urticaria-like lesions, progressing from the injection site on the abdomen, appeared in 5.17 ± 3.60 days after the first appearance of localized reaction, while laboratory test results revealed essential peripheral blood eosinophilia. All rashes in the 6 cases subsided in 2–5 weeks after drug withdrawal. After delivery, 5 of 6 cases received complete skin tests to evaluate drug hypersensitivity. Results presented positive in the intradermal test within 7 days. Both the skin prick test and skin patch test were negative. Localized skin reactions and generalized urticaria-like adverse drug reactions were considered as definitely and probably caused by nadroparin calcium injection, respectively.

Conclusion

Subcutaneous injection of nadroparin calcium in pregnant women appears to be at risk of localized and generalized urticaria-like adverse drug reaction. It is important to follow up the pregnant woman during nadroparin calcium injection for evaluating adverse drug reactions. Timely detection of symptoms is pivotal in early diagnosis and treatment of adverse drug reactions.

Risk Factors for Immediate-Type Local Anesthetic Hypersensitivity Reactions in Pediatric Patients: A Retrospective Case-Control Study

Background

Local anesthetics (LA) are relatively safe and rarely cause immediate hypersensitivity reactions. The data on immediate LA hypersensitivity and its risk factors in children are limited.

Aim

To evaluate risk factors of immediate LA hypersensitivity.

Methods

The retrospective case-controlled study included 17 patients with confirmed immediate LA hypersensitivity. For each patient, three age- and gender-matched control subjects were included in the study. LA hypersensitivity was excluded by skin tests and subcutaneous drug provocation tests in all control subjects.

Results

The most common allergic assessment in the patient/control group was for lidocaine (n=5; 29.4%, vs n=23; 45.1%). Suspected LA hypersensitivity reactions were found to be associated with cutaneous manifestations in 14 (82.4%) patients and in 7 (13.7%) of the controls. A history of exposure to local anesthetics twice or more was present in 11 (64.7%) patients vs 6 (11.8%) controls. In conditional regression analysis, repeated LA exposure (≥2) and cutaneous findings were determined as significant risk factors (Odds Ratio [OR]:5.7; 95% Confidence Interval [CI]:1.2–27.1; P=0.029 and (OR:17.3; 95% CI:3.6–82.5; P<0.001, respectively).

Conclusion

Cutaneous manifestations and a history of LA exposure twice or more were predictive factors for LA allergy confirmed by skin test in children.

Intradermal testing increases the accuracy of an immediate-type cefaclor hypersensitivity diagnosis

Background

Hypersensitivity reactions to cefaclor have increased in accordance with its frequent use. However, only limited data are available on the diagnostic value of skin tests for these conditions, particularly intradermal tests (IDTs).

Objective

To evaluate the clinical usefulness of IDT compared to the ImmunoCAP test in patients with cefaclor-induced immediate-type hypersensitivity.

Methods

We conducted a retrospective chart review from January 2010 to June 2020 of adult subjects from 2 tertiary hospitals in Korea with a history of suspected immediate-type hypersensitivity to cefaclor, and who had undergone ImmunoCAP and IDT.

Results

Overall, 131 subjects diagnosed with cefaclor hypersensitivity were included in the analysis. Fifty-nine patients (59/131, 45.04%) were positive in both IDT and ImmunoCAP. Fifty-four (54/131, 41.22%) and 6 (6/131, 4.58%) subjects showed positive results only with IDT or the ImmunoCAP test, respectively. Twelve subjects (12/131, 9.16%) were negative by both tests but reacted positively in a drug provocation test. The frequency of IDT positivity was similar regardless of the severity of reactions. However, positivity of ImmunoCAP was lower in subjects with mild reactions compared to those with anaphylaxis. Regarding the diagnosis of cefaclor hypersensitivity, the overall sensitivity of IDT and ImmunoCAP was 0.863 and 0.496, respectively while the specificity was 1. The combination of IDT and ImmunoCAP further increased this sensitivity to 0.908.

Conclusion

IDT was more sensitive than ImmunoCAP for the diagnosis of cefaclor allergy, regardless of the severity of the hypersensitivity reaction. Therefore, we recommend a combination of IDT and ImmunoCAP for the diagnosis of cefaclor hypersensitivity.

Contrast Medium Hypersensitivity: A Large Italian Study with Long-Term Follow-Up

Hypersensitivity reactions (HRs) to contrast media (CM) are a major problem. We compared differences of HRs to iodinated contrast media (ICM) versus gadolinium-based contrast media (GBCM), collecting data on prevalence, type, latency and severity. Secondly, the predisposition to perform new contrast tests, use of premedication and possible appearance of new reactions were explored in a long-term follow-up of 5 years. Clinical data, comorbidities, skin test (ST) results, re-exposure to CM procedures with any new reactions, premedication and CM used were collected. In a retrospective single-center study, 350 patients with mild to moderate HRs were enrolled. Asthma, food allergy, non-allergic drug hypersensitivity and neurologic disease were significantly more frequent in patients with HRs to GBCM compared to the high evidence of cardiovascular disease and history of cancer in patients with HRs to ICM. A marked delay in performing STs was reported by patients with negative results (66 months, p < 0.01). Iomeprol, iopamidol and gadobenic acid were the culprit CM most involved in HRs in patients with positive STs. During follow-up, 7.1% of responders reported new HRs to CM despite negative STs, premedication and infusion of alternative CM in most cases.

New diagnostıc perspectives in the management of pediatrıc beta-lactam allergy

Since overdiagnosis of beta-lactam (BL) allergy is common in the pediatric population, delabeling is a critical part of antimicrobial stewardship. Undesirable consequences of inaccurate BL allergy labeling can be handled by incorporating traditional delabeling or newer risk-based strategies into antibiotic stewardship programs. Conventional assessment of BL allergy relies upon a stepwise algorithm including a clinical history with skin testing followed by drug provocation tests (DPTs). However, a growing number of studies highlighted the suboptimal diagnostic value of skin testing in children. Recently, there has been a paradigm shift in the practice of BL allergy assessment due to recent challenging data which emphasize the safety and accuracy of direct DPTs in children with a suspicion of non-immediate mild cutaneous reactions such as maculopapular eruption, delayed urticaria, and possibly also for benign immediate reactions such as urticaria/angioedema. Identifying low-risk BL allergy patients, in whom skin tests can be skipped and proceeding directly to DPTs could be safe, has become a hot topic in recent years. New risk stratification and predictive modeling studies that have the potential to better predict BL allergy risk status have recently been introduced into the field of drug allergy, particularly in adults. However, in contrast to adults, risk assessment studies in children are rare, and optimal risk definitions are controversial. In the coming years, promising potential methods to elucidate the predictors of BL allergy in children will require multidimensional approaches that may include predictive analytics, artificial intelligence techniques, and point-of-care clinical decision tools.

Patch testing in Drug reaction with eosinophilia and systemic symptoms (DRESS): a literature review

The literature on positive patch test results in drug reaction with eosinophilia and systemic symptoms (DRESS) is reviewed. 105 drugs were identified that have together caused 536 positive patch tests in 437 patients suffering from DRESS. By far most reactions (n=145) were caused by carbamazepine, followed by amoxicillin, isoniazid, phenytoin, ethambutol, fluindione, phenobarbital, rifampicin, and ceftriaxone; 43 drugs each caused a single case only. The drug classes causing the highest number of reactions are anticonvulsants (39%), beta-lactam antibiotics (20%), antituberculosis agents (11%), non-beta-lactam antibiotics (6%) and iodinated contrast media (5%). The sensitivity of patch testing (percentage of positive reactions) is high for anticonvulsants (notably carbamazepine), beta-lactam antibiotics (notably amoxicillin) and possibly iodinated contrast media. Allopurinol and sulfasalazine frequently cause DRESS, but never give positive patch tests. Patch testing in DRESS appears to be safe, although mild recurrence of DRESS symptoms, mostly skin reactions, may not be rare. Multiple drug hypersensitivity was found to occur in 16% of all patients, but it is argued that the true frequency is (far) higher. Clinical aspects of DRESS, including diagnosing the disease and identifying culprit drugs (patch tests, intradermal tests, in vitro tests, challenge tests) are also provided, emphasizing the role of patch testing. This article is protected by copyright. All rights reserved.

Safety and efficacy of rapid drug desensitization in children

BACKGROUND

Any drug taken at the recommended dosage may cause hypersensitivity reactions (DHR). Rapid drug desensitization (RDD) protocols have been developed in the case of a confirmed or highly suspected HSR to allow safe administration of the medicine when there is no alternative drug or in the presence of a less effective or more toxic alternative. The aim of this study was to evaluate the characteristics of children who underwent desensitization, the safety and efficacy of RDD in children, as well as, the characteristics and management of breakthrough reactions.

METHOD

This retrospective study concerned children who underwent RDD due to physician-diagnosed HSRs during or up to 48 hours after the infusion of various drugs between February 2010-February 2021. Patients with a chronic disease needing chronic drug usage and acute infections seen in patients with chronic diseases were included. The results of RDD were documented.

RESULTS

The study included 48 patients [8.1(IQR = 3.32-13.4) years, 60.4% male] with 58 HSRs of which 62.1% were classified as moderate and 5.2% as severe. Most of the patients were being treated for leukemia (41.7%), solid tumors (29.2%), and infections (6.3%). Skin tests were done for 41 out of 58 HSRs in 35 patients, and twenty of them were positive. A total of 269 RDDs were performed for 18 different drugs. Ninety percent of desensitizations were achieved with no reaction, and 3.7% and 5.6% with mild and moderate reactions, respectively. In multivariate analysis, skin test positivity was the only risk factor for breakthrough reactions (OR = 8.5, CI = 1.72-42.15, p = .009).

CONCLUSION

We demonstrated the safety and efficacy of RDD in childhood, thereby offered the first line treatment options to children with chronic diseases with hypersensitivity reactions (HSRs).

Results of patch testing in Acute generalized exanthematous pustulosis (AGEP): a literature review

The literature on positive patch test results in acute generalized exanthematous pustulosis (AGEP) is reviewed. 93 drugs were identified that have together caused 259 positive patch tests in 248 patients suffering from AGEP. The drug classes causing the highest number of reactions are beta-lactam antibiotics (25.9%), other antibiotics (20.8%), iodinated contrast media (7.3%) and corticosteroids (5.4%), together accounting for nearly 60% of all reactions. The highest number of reactions to individual drugs was to amoxicillin (n=36), followed by pristinamycin (n=25), diltiazem (n=14), amoxicillin-clavulanic acid (n=13), clindamycin (n=11) and iomeprol (n=8); 59 of the 93 drugs each caused a single case only. The "Top-10" drugs together caused over 50% of all reactions. The sensitivity of patch testing (percentage of positive reactions) in patients with AGEP is largely unknown, but may generally be around 50%, which also applies to pristinamycin. Patch testing in AGEP appears to be safe, although mild recurrence of AGEP skin symptoms or other rashes may occur occasionally. Clinical aspects of AGEP, including epidemiology, etiology and pathophysiology, clinical features, histology, treatment, and prognosis are briefly presented, as are diagnosing the disease and identifying the culprit drugs with patch tests, intradermal tests, in vitro tests, and challenge tests. This article is protected by copyright. All rights reserved.

The controversy of drug hypersensitivity in patients with cystic fibrosis and review of the literature

BACKGROUND

Cystic fibrosis (CF) is reported to be a risk factor for drug hypersensitivity. However, there are conflicting data about true prevalence of drug hypersensitivity in children with CF.

METHODS

The suspicious drug hypersensitivity reactions (DHRs) of children with CF were enquired by the European Network for Drug Allergy (ENDA) questionnaire, and skin tests and/or drug provocation tests were performed according to the established guidelines.

RESULTS

Two hundred and nineteen children (48.9% boys; median [IQR] age, 8.4 years [4.8-12.4 years]) with cystic fibrosis were included in the study, among which 22 patients with 24 suspected DHRs were evaluated. Most of the suspected DHRs were of non-immediate (n = 16, 66.6%) type, and the offending drugs were amoxicillin-clavulanic acid (n = 7), macrolides (n = 4), trimethoprim-sulfamethoxazole (TMP/SMX) (n = 2), piperacillin-tazobactam (n = 1), pancrelipase (n = 1), and ursodeoxycholic acid (n = 1). Eight (33.3%) of the DHRs were classified as immediate (ceftriaxone [n = 2], ceftazidime [n = 2], meropenem [n = 1], AmBisome [n = 2], and vancomycin [n = 1]). The main clinical presentations were maculopapular eruption (41.6%) and urticaria (37.5%), accompanied by angioedema (8.3%), flushing (12.5%), and vomiting (8.3%). Nine skin tests (with beta-lactam protocol in 6 patients) and 24 DPTs were performed, and none of the skin tests revealed a positive result; however, 2 DPTs with TMP/SMX were positive.

CONCLUSION

Actual drug hypersensitivity was demonstrated in 2 of 219 patients (0.9%) with non-beta-lactam antibiotics. These results conflict with previous researches that showed higher drug hypersensitivity rates but are consistent with some recent studies. Allergological diagnostic workup is mandatory in patients with cystic fibrosis in case of a suspicious DHR.