Nonimmediate Hypersensitivity Reactions Research Articles

Simplifying The Drug Provocation Test in Non-Immediate Hypersensitivity Reactions to Amoxicillin in Children: The Experience of a Tertiary Care Allergy Unit.

Simplifying The Drug Provocation Test in Non-Immediate Hypersensitivity Reactions to Amoxicillin in Children: The Experience of a Tertiary Care Allergy Unit.

The Safety of the Direct Drug Provocation Test in Beta-Lactam Hypersensitivity in Children: A Systematic Review and Meta-Analysis

Direct drug provocation test (DPT) without prior skin testing (ST) has been investigated in children suspected of being at risk for beta-lactam (BL) hypersensitivity reaction (HSR). However, no systematic review and meta-analysis has investigated the efficacy and safety of direct DPT for BL-HSR in children. To investigate the prevalence of BL-HSR by direct DPT and the safety of direct DPT in children. We searched MEDLINE, EMBASE, Web of Science, and CINAHL from their inception to July 23, 2022, for studies that performed direct DPT in children with suspected BL-HSR, or for studies that performed DPT in all cases with ST results, but they ignored the ST results. The true prevalence was defined as the proportion of children who experienced an HSR during direct DPT. Safety was determined according to the proportion of children who developed a dangerous reaction following DPT. Twenty-eight studies with 8,334 direct challenges were included. Fifteen studies included patients who presented with either immediate or nonimmediate HSR, and the majority of the index reactions were nonsevere. Amoxicillin/amoxicillin-clavulanic acid was the most commonly used during the DPT. The pooled prevalence of confirmed BL-HSR was 5.23% (95% CI 4.17-6.39; I2= 72%). Immediate and nonimmediate HSR were reported in 0.8% (95% CI 0.43-1.25; I2= 55.1%) and 3.69% (95% CI 2.66-4.87; I2= 79.77%), respectively. Severe reactions were found in 3 cases with the frequency of 0.036% (95% CI 0.012-0.112; I2= 0%). The prevalence of BL-HSR by direct DPT was 5.23%, and the frequency of severe reactions from direct DPT was very low (0.036%). Our findings support direct DPT as a safe and effective delabeling tool in children with suspected nonsevere BL-HSR.

Management of adverse reactions induced by chemotherapy drugs.

There is a broad spectrum of chemotherapy-induced adverse reactions. Hypersensitivity reactions are being extensively studied as they can affect the ideal treatment. The goal of this review is to describe the current management of adverse reactions to chemotherapy, focusing on hypersensitivity events. The range of possible desensitization protocols is increasing, as well as the delabeling algorithms and diagnostic tools. One-bag desensitization protocols, omalizumab use in immediate hypersensitivity reactions, slow desensitization protocols in nonimmediate hypersensitivity reactions and standardization of skin tests for platinum drugs, are some examples. The handling of adverse reactions to chemotherapy is evolving, with the increasing identification of hypersensitivity reactions and the development of strategies for their management, to maintain the culprit drug.

Non-immediate hypersensitivity reactions to iomeprol: Diagnostic value of skin tests and cross-reactivity with other iodinated contrast media.

Iodinated contrast media produce non-immediate hypersensitivity reactions (NIHR). The goal of this prospective study was to determine the utility of skin tests and the subsequent tolerance to negative skin-tested iodinated contrasts in patients with NIHR caused by iomeprol. Prick and intradermal tests with iomeprol, iopamidol, iopromide, and iobitridol were performed in all patients. IV challenge with the causative contrast (iomeprol in 90%) was made if skin tests were negative. In case of a positive skin test with the causal contrast, or a positive challenge test with it, IV challenge test with an alternative, negative skin-tested contrast was performed in all patients. Skin tests were positive in 47.6% (20/42) of patients with NIHR induced by iomeprol. Of the 66 challenge tests performed with negative skin-tested iodinated contrasts, tolerance was confirmed in 35 (53%): 32 iomeron, 2 iobitridol, 1 iopamidol. Cross-reactivity between iomeprol and iopamidol was 22% (4/20 in patients with positive skin tests and 5/21 in patients with negative skin tests). Sensitivity of the skin tests was less than 50% NIHRs due to iomeprol, while the negative predictive value of skin tests in patients who tolerated challenges with alternative contrasts (mainly iopamidol) was 53% (35 tolerated out of 66 performed). The cross-reactivity between iomeprol and iopamidol is high.

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

BackgroundThe beta-lactam antibiotic amoxicillin and the beta-lactamase inhibitor clavulanic acid in combination with amoxicillin are known to cause both immediate- and nonimmediate-type hypersensitivity. ObjectiveTo characterize a large cohort of patients with a history of amoxicillin or amoxicillin-clavulanic acid hypersensitivity. MethodsA retrospective analysis was conducted of the demographics, presentation, investigation, and management of 331 patients presenting to 1 allergy center with a history of hypersensitivity to amoxicillin or amoxicillin-clavulanic acid. ResultsHypersensitivity was confirmed in 37 of 221 patients (17%) who took amoxicillin and 47 of 110 patients (43%) who took amoxicillin-clavulanic acid as the index drug.In immediate hypersensitivity, skin test results confirmed the diagnosis in 66 of 139 patients (47%). Penicillin cross-reactivity was observed in 16 of 36 patients (44%). Of the 16 patients who were cross-reactive, 13 (81%) reacted to amoxicillin-clavulanic acid as the index drug. All patients who had negative skin test results (73/139) underwent drug provocation. The negative predictive value of skin tests was 89%.In nonimmediate hypersensitivity, delayed intradermal tests confirmed diagnosis in 12 of 170 patients (7%). Of the 12 patients whose skin test results were positive, 8 (67%) presented with drug reaction with eosinophilia and systemic symptoms. All patients with a negative skin test result (158/170) underwent drug provocation. The negative predictive value of skin tests was 95%. Penicillin cross-reactivity was observed in 3 of 12 patients (25%).Ten patients were diagnosed with hypersensitivity to clavulanic acid. ConclusionThe negative predictive value of skin tests in both immediate and nonimmediate hypersensitivity reactions is excellent and excludes severe allergy. Nonimmediate 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, typically involving benzylpenicillin. A minority of patients were allergic to clavulanic acid.

Converter Phenotype: A New Profile That Is Not Exclusive to Taxanes.

Introduction: Phenotype I hypersensitivity reactions are the most commonly reported drug reactions; however, precision medicine has made it possible to characterize new phenotypes. A recent communication proposed the existence of a “converter phenotype,” which would affect patients who present non-immediate hypersensitivity reactions and in subsequent exposures develop immediate hypersensitivity reactions. This study aimed to describe the clinical characteristics of converter phenotype reactions and their evolution during desensitization to chemotherapeutic drugs and monoclonal antibodies.Methods: We retrospectively reviewed our database of patients undergoing desensitization to chemotherapy or biological agents and selected those with a converter phenotype. Demographic and clinical characteristics of the patients, the results of skin tests, tryptase and IL-6 levels, and desensitization outcomes were assessed.Results: Of 116 patients evaluated, 12 (10.3%) were identified as having a converter phenotype. The median interval between drug exposure and reaction was 90.6 h (range 8-288 h). After the conversion, phenotype I was the most frequent (58.3%), followed by cytokine release reactions (33.3%). Fifty-one desensitizations were undertaken and all treatments completed, with 10 (19.6%) breakthrough reactions. No new changes in the phenotype were detected.Conclusions: The symptoms of non-immediate drug hypersensitivity reactions may indicate the need for an early allergological evaluation to assess the risk of future immediate drug reactions. Clinical characteristics, skin test results, and biomarkers can help predict responses to rapid drug desensitization, guiding clinicians on how to optimize therapy delivery while maintaining patient safety.

Nonimmediate Hypersensitivity Reaction to Rifaximin Confirmed With a Drug Challenge Test

Nonimmediate Hypersensitivity Reaction to Rifaximin Confirmed With a Drug Challenge Test

Inherent clinical properties of non-immediate hypersensitivity to iodinated contrast media.

Iodinated contrast media (ICM) is a frequently used compound in radiology. Non-immediate hypersensitivity reactions (HSR) appear when a patient leaves the department and usually are undocumented. True hypersensitivity in this group is rarely proved. Single-centre 2014-2018 data were retrospectively analysed. HSR to ICM were classified and investigated according to the time of occurrence (immediate <1hour, non-immediate >1hour). ENDA questionnaire and skin tests (prick or intradermal test) were performed according to ENDA/EAACI recommendations. 69 patients with a clinical history of HSR to ICM were identified, 72.46% were females (n=50). The average age was 56 (SD±13.16) years. Non-immediate HSR occurred in 28.99% (n=20) patients. The suspected culprit drugs were: iodixanol 20% (n=4), iopromide 5% (n=1), diatrizoate 10% (n=2) and iohexol 10% (n=2). Among non-immediate HSR 96.00% (n=19) of patients had skin rashes. A statistically significant correlation was found between the clinical symptoms and the type of reaction (p-value <0.05): isolated skin manifestations mostly occurred in non-immediate HSR 75.00% (n=15). Only 13.04% (n=9) of all the patients were proved to be allergic to a certain ICM after the proposed diagnostic workup. One-third of the hypersensitivity reactions investigated were classified as non-immediate type. Most of them manifested with isolated skin symptoms. The most frequent culprit drug encountered was iodixanol. The overall non-immediate hypersensitivity confirmation rate after diagnostic evaluation was only 15%.

Practice parameters for diagnosing and managing iodinated contrast media hypersensitivity.

Immediate and nonimmediate hypersensitivity reactions to iodinated contrast media (ICM) have been reported to occur in a frequency of about 0.5%-3% of patients receiving nonionic ICM. The diagnosis and management of these patients vary among guidelines published by various national and international scientific societies, with recommendations ranging from avoidance or premedication to drug provocation test. This position paper aims to give recommendations for the management of patients with ICM hypersensitivity reactions and analyze controversies in this area. Skin tests are recommended as the initial step for diagnosing patients with immediate and nonimmediate hypersensitivity reactions; besides, they may also help guide on tolerability of alternatives. Re-exposition or drug provocation test should only be done with skin test-negative ICMs. The decision for performing either re-exposition or drug provocation test needs to be taken based on a risk-benefit analysis. The role of in vitro tests for diagnosis and pretreatment for preventing reactions remains controversial.

Assessment of immediate and non-immediate hypersensitivity contrast reactions by skin tests and provocation tests: A review.

Introduction:Allergic and nonallergic hypersensitivity reactions to iodinated contrast media (ICM) and gadolinium-based contrast media are classified as immediate or non-immediate hypersensitivity reactions (IHR and NIHR), respectively. Skin tests and provocation tests are recommended for the evaluation of hypersensitivity reactions to contrast agents; however provocations are not common in clinical practice.Methods:A MEDLINE search was conducted to investigate studies comprising both skin tests and provocation tests that evaluated hypersensitivity reactions to ICM.Results:Nineteen studies were identified that reported on skin tests, followed by provocations. In the case of IHR to ICM, 65/69 (94%) patients with a positive skin test for the culprit media tolerated a challenge with a skin-test-negative alternative ICM. In IHR to ICM with a negative skin test for the culprit media, provocations were positive in 3.2%–9.1% patients. In the case of a NIHR to ICM with a positive skin test, provocation with a skin-test-negative agent was tolerated in 75/105 (71%) of cases. In NIHR with a negative skin test for the culprit agent, re-exposure to the culprit or an alternative was positive in 0%–34.6% patients. Provocations with the same ICM in skin test positive patients with IHR or NIHR were positive for a majority of the patients, although such provocation tests were rarely performed. Data on hypersensitivity reactions, skin tests and provocations with gadolinium-based contrast media were limited; however, they exhibited a pattern similar to that observed in ICM.Conclusion:In both ICM and gadolinium-based contrast media, the risk of an immediate repeat reaction is low when skin tests are negative. In contrast, a provocation with a skin-test-positive contrast medium showed a high risk of an immediate repeat hypersensitivity reaction. Therefore, a thorough medical history is necessary, followed by skin tests. A provocation is recommended, for diagnostic work-up, when the diagnosis is uncertain.

Non-Immediate Hypersensitivity Reaction to Rifaximin Confirmed With a Drug Challenge Test

Non-Immediate Hypersensitivity Reaction to Rifaximin Confirmed With a Drug Challenge Test

Altered levels of complement components associated with non-immediate drug hypersensitivity reactions

Nonimmediate drug hypersensitivity reactions (niDHRs) range from mild-type maculopapular exanthema (MPE) to severe type Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) with unentirely clarified pathogenesis. This study sought to explore whether complement components participated in niDHRs. The participants comprised of three groups as follows: MPE (n = 65), SJS/TEN (n = 13, contains 7 SJS, 2 SJS-TEN overlap and 4 TEN), and equal healthy controls (n = 78). Skin pathological changes were confirmed by hematoxylin and eosin staining. The mRNA and protein levels of complement components were assessed. In the MPE group, there were no alterations in complement components at the protein and mRNA levels found except for a decrease in factor H mRNA. In the SJS/TEN group, up-regulated levels of C3aR and C5aR mRNA and down-regulated factor H mRNA levels in blood were noted. A lower plasma protein level of C3, Factor H and a higher level of C3a, C5, C5a, C5b-9, Factor B (p < 0.05) were found in the SJS/TEN group compared with in the control (p < 0.05). In SJS/TEN skin lesions, indirect immunofluorescence assays showed positive specific staining for C5b-9, but not C3. Both C3aR and C5aR were positive staining in the SJS/TEN samples, while staining for C1q, mannose-binding lectin (MBL), Factor B, and Factor H were only weak or negative. The findings reported here are the first to define the expression profiles/extent of the presence of various complement components at the mRNA and protein levels in niDHRs, especially in SJS/TEN. These altered complement components might, at least in part, be integral to the mechanisms underlying the pathogeneses of SJS and TEN.

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

To determine if repeated doses of a β-lactam antibiotic are required to reproduce a nonimmediate hypersensitivity reaction in children.This retrospective observational study included 97 patients younger than 14 years of age with history of at least 1 reaction to a β-lactam antibiotic and with symptoms that began at least 6 hours after the first dose of the implicated medication.All patients underwent a 1-day in-hospital graded provocation test, with a cumulative dose of 65% of the daily dose of the β-lactam antibiotic under study, followed by hospital observation for 2 hours. If no reaction appeared over the same amount of time between dosing and symptoms during the index reaction, the patient was instructed to continue 2 daily antibiotic doses at home over the same number of days it took for the index reaction to appear. The total duration of study was variable for each patient.A positive reaction was recorded in 14 patients (14.4%). The hospital provocation triggered 3 immediate reactions and 8 delayed reactions. The home provocation triggered 1 immediate reaction and 2 delayed reactions. The most frequent manifestation of an adverse reaction was a maculopapular exanthem. Previous symptoms, implicated medication, and demographic characteristics of patients (with exception of sex) were not predictors for the appearance of delayed reactions. Male sex and a history of more than 1 previous reaction with any β-lactam antibiotic were associated with immediate or late reactions during hospital provocation.Nonimmediate reactions to β-lactam antibiotics in children may be triggered with a 1-day provocation test. The authors suggest a 1-day provocation test followed by an observational period of at least the time interval observed in the index reaction. If this provocation is negative, an extended home provocation could be pursued.The results of the current study are encouraging, with the minority of studied patients exhibiting adverse symptoms, most of which were triggered during the hospital rather than the home provocation. Data from the current study do not exclude the possibility that reactions may occur hours to days after a single-day provocation attempt. The authors pose the question of whether all patients who will react are able to be provoked with a single-day attempt with prolonged subsequent observation. Additional study is needed to assess larger numbers of children with nonimmediate adverse reactions to β-lactam antibiotics. Additional data on risk assessment and pretest predictive measures will lead to benefits both for individual patients and community antibiotic stewardship.

A practical 16-day desensitization protocol in lenalidomide-induced non-immediate hypersensitivity reactions

BackgroundDesensitization in immediate-type hypersensitivity reactions (HRs) caused by chemotherapeutics is well described and standardized for many drugs. However, there are no standardized protocols in non-immediate HRs. ObjectiveTo evaluate the effectiveness of a 16-day desensitization protocol in the non-immediate HRs induced by lenalidomide. MethodsAccording to our previously published slow desensitization protocol, we desensitized patients who had experienced non-immediate HRs attributable to lenalidomide. The protocol was started with the 1/100 of the daily-prescribed dose in milligrams of the culprit drug; then the doses were slowly increased to complete the procedure in 16 days. Demographic and clinical features of the patients were further appraised. ResultsTen patients (mean age was 64.7 ± 10.8 years; 7 male) were successfully desensitized to lenalidomide. The mean reaction time was 7.3 ± 3.9 days in the history, and the reaction types were delayed urticaria (n = 4), eczematous rash (n = 3), and maculopapular eruptions (n = 3). The desensitization was successfully completed in 16 days in 9 patients. In 1 patient, maculopapular eruptions developed on the 11th day, and the patient was treated with corticosteroids. We repeated the previous tolerated dose longer and completed with a slower dose increasement, and the targeted dose was achieved in 35 days. ConclusionThe 16-day desensitization protocol seemed to be safe and effective in the non-immediate type drug HRs caused by lenalidomide.

The Limited Value of Prolonged Drug Challenges in Nonimmediate Amoxicillin (Clavulanic Acid) Hypersensitivity

Misdiagnosis of amoxicillin (clavulanic acid) (AX(/CL)) hypersensitivity has serious consequences. A drug challenge (DC) is the final diagnostic to affirm or infirm AX(/CL) hypersensitivity. However, uncertainties remain whether a prolonged drug challenge (pDC) should benefit the diagnosis of a nonimmediate AX(/CL) hypersensitivity. To assess the added value of a standardized 7-day pDC in the diagnosis of nonimmediate or unclear penicillin hypersensitivity. A total of 132 patients with a history of a nonimmediate hypersensitivity reaction or an unclear reaction to AX(/CL) or an undefined penicillin with a negative diagnostic workup including a single-day DC (DC) with AX(/CL) were selected. In all these patients, an additional pDC with AX(/CL) was planned. Thirteen patients started the pDC immediately after the DC. To ensure that hypersensitivity symptoms manifesting during the pDC course do not result from the DC, in the remaining 119 patients, the pDC was scheduled after a washout of 1 week. A total of 128 patients (12 without washout, 116 with washout) completed the pDC. Three patients reacted with a mild maculopapular exanthema. However, the value of a pDC was evidenced in only 1 patient who reacted during her pDC after an uneventful washout. In 2 patients pDC was cancelled because they reacted during the washout. A pDC is of limited added value to the diagnostic algorithms of nonimmediate hypersensitivity reaction or unclear hypersensitivity reactions to AX(/CL). In our hands, the traditionally recommended diagnostic algorithm that offers a 1-day DC as a final diagnostic in patients with negative workup for AX(/CL) is appropriate.

Short and extended provocation tests have similar negative predictive value in non-immediate hypersensitivity to beta-lactams in children

Introduction and objectivesDrug provocation tests (DPTs) are the gold-standard method to diagnose non-immediate hypersensitivity reactions (NIHSR) to beta-lactam antibiotics (BL) in children. Our aim was to compare the negative predictive value (NPV) of one-day (short) DPT versus 3–7 days (extended) DPT for the diagnosis of NIHSR to BL in paediatric age. A secondary aim was to compare confidence on drug re-exposure after short and extended negative DPTs. MethodsThe occurrence of HSR on drug re-exposure and drug refusal after negative diagnostic DPTs were evaluated in children/adolescents with a history of NIHSR to BL using a questionnaire performed six months to ten years after DPT. Patients were divided into two groups according to the protocol performed: short DPT vs. extended DPT. ResultsWe enrolled 212 children and adolescents (86 females, 126 males, mean age at DPT 5.52 years, p25=3 years, p75=7.25 years): 69 tested with short DPT, and 143 with extended DPT. The NPV of both types of DPT together was 95.2%. The NPV of short DPT was 97.5% and the NPV of extended DPT was 93.8% (p=0.419). After negative DPT, beta-lactams were refused by carers in 14.75% of the children requiring subsequent treatment, 6.98% in the short DPT group and 18.99% in the extended DPT group (p=0.074). ConclusionsIn our paediatric sample, prolonging drug administration did not increase the NPV of diagnostic DPT for NIHSR to BL or reduce drug refusal. Altogether, the data here reported suggest that, however intuitive, prolonging DPT is not beneficial in the parameters analysed.

SUCCESSFUL RAPID ORAL DESENSITIZATION TO SULFASALAZINE: A NOVEL 11 STEP PROTOCOL

Introduction Sulfasalazine (SSZ) is usually associated with non-immediate hypersensitivity reactions. Immediate hypersensitivity reactions from sulfasalazine have not been well described. Case Description A 58-year-old female was evaluated for SSZ hypersensitivity reaction. She had a history of inflammatory arthritis with persistent arthralgia despite oral prednisone and methotrexate. The patient had a history of recurrent infections in the setting of hypogammaglobulinemia thus treatment with biologic agents was deferred given concern for worsening hypogammaglobulinemia. SSZ was prescribed 5 years prior for inflammatory arthritis, however, the patient developed bilateral ear pruritus and cough with wheezing within 30 minutes of receiving the drug. The patient deferred skin testing to sulfasalazine. The patient underwent an open oral challenge with 125 mg of SSZ and developed bilateral ear pruritus and coughing within 20 minutes of administration; vital signs were stable without evidence of hypotension. She received antihistamines with resolution of symptoms 40 minutes thereafter. Given that no alternative disease-modifying anti-rheumatic drug was identified, the patient underwent a successful novel 11-step oral desensitization to sulfasalazine 500 mg following pre-medications (Table 1). The patient only developed mild throat pruritus during step 6 without further reactions. The patient has tolerated SSZ without further reactions till date. Discussion Immediate reactions to SSZ are rare and most previous limited number of published desensitization protocols were intended for non-immediate hypersensitivity reactions. We present a successful oral desensitization protocol to SSZ in a patient with a previous immediate hypersensitivity reaction to SSZ which was confirmed by an open oral challenge.

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

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

Prevalence of Hypersensitivity Reactions in Children Associated with Acetaminophen: A Systematic Review and Meta-Analysis

Background: Acetaminophen is the most commonly used antipyretic in children. However, there are limited data assessing hypersensitivity reactions related to acetaminophen usage. Objectives: To conduct a systematic review to characterize reported reactions to acetaminophen in adults and children, and perform a meta-analysis to assess the prevalence of acetaminophen hypersensitivity in children with a suspected acetaminophen allergy. Methods: We performed a systematic review of studies reporting hypersensitivity reactions to acetaminophen by searching 2 electronic databases. From the selected studies, we included those assessing the prevalence of acetaminophen hypersensitivity by performing oral challenge in our meta-analysis. Results: Eighty-five studies were included in the systematic review, assessing a total of 1,030 participants. Immediate (within 1 h of exposure) hypersensitivity reactions were reported in > 25% of the articles, while cutaneous nonimmediate reactions were similarly reported in about 25% of the articles. The remaining articles reported Steven-Johnson syndrome/toxic epidermal necrolysis, fixed drug eruptions, and cross-intolerance reactions. Five pediatric studies were included in our meta-analysis. The prevalence of acetaminophen hypersensitivity reaction among children undergoing oral challenge was 10.1% (95% confidence interval 4.5–15.5). Conclusion: Future studies assessing the risk of immediate and nonimmediate hypersensitivity reactions to acetaminophen and elucidating the mechanism of acetaminophen hypersensitivity reactions are required.

Value of drug provocation test in non-immediate hypersensitivity reactions to betalactams in pediatric age

Value of drug provocation test in non-immediate hypersensitivity reactions to betalactams in pediatric age