Results of NSAID provocation tests and difficulties in the classification of children with nonsteroidal anti-inflammatory drug hypersensitivity

Guiding Drug Provocation Testing for Ibuprofen Hypersensitivity in a Pediatric Population: Development of the I3A Risk-Stratification Tool

BACKGROUND

Ibuprofen is a main cause of drug hypersensitivity reactions in children. The gold standard for diagnosis is the drug provocation test (DPT).

OBJECTIVE

We aimed to create a clinical risk-stratification tool to guide this high-risk procedure.

METHODS

We prospectively recruited children with suspected ibuprofen hypersensitivity between January 2017 and March 2024. Using stepwise bidirectional multivariable logistic regression, we calculated a predictive score for a positive ibuprofen DPT.

RESULTS

Eighty-two patients with a median age of 5.9 years (interquartile range: 3.4-11.1 years) had an ibuprofen DPT. Eighteen (22.0%) patients had a positive challenge, with an anaphylactic reaction for 11 (61.1%). The I3A score (acronym for ibuprofen, 3As: angioedema, anaphylaxis, age, cutoff of 3) encompasses the following items: angioedema (2 points), anaphylaxis (1 point), and age at reaction ≥10 years old (1 point). The area under the curve of the I3A score was 0.84, and the optimal cutoff of <3 conferred a sensitivity of 84.4% (95% confidence interval [CI]: 66.7%-100.0%) and a specificity of 83.3% (95% CI: 75.0%-92.2%). The negative predictive value was estimated at 94.7% (95% CI: 90.0%-100.0%), and the positive predictive value at 60.0% (95% CI: 46.2%-76.2%). The relative risk of reacting to a challenge in the group I3A 3-4 compared with 0-2 was 11.4 (95% CI: 3.62%-35.7%, P < .001). Anaphylaxis after DPT was observed in 9 of 25 (36.0% [95% CI: 16.0%-56.0%]) in the high-risk group as compared with 2 of 57 (3.5% [95% CI: 0.0%-8.8%]) in the low-risk group (relative risk 10.3 [95% CI: 2.4%-43.5%]).

CONCLUSIONS

We generated a risk-stratification tool to identify children at low risk of reacting to ibuprofen challenges. Further validation is required in external cohorts.

Is a Drug Allergy in a Patient's History Real? Our Experience with Diagnostic Drug Provocation Tests

Background and Objectives: Early-type drug hypersensitivity reactions (DHRs) are observed within the first 1-6 h and most commonly manifest as urticaria and/or angioedema. Detailed anamnesis, skin prick tests (SPTs), intradermal tests (IDTs), and oral/intramuscular/intravenous drug provocation tests (DPTs) can be used to identify the drug responsible. We aimed to evaluate the demographic characteristics, responsible drugs, DHR types, and DPT results used in the diagnosis of drug allergy in patients who presented to our clinic with suspected drug allergies. Materials and Methods: The medical records of patients who presented with a suspicion of an early-type DHR between February 2019 and December 2024 were retrospectively evaluated through the hospital information management system. A total of 188 adults who underwent diagnostic drug testing were included. Results: The diagnosis of drug allergy was confirmed in 51 (27%) patients. In 137 (73%) patients, the diagnosis of drug allergy was excluded after DPTs. In 78 of the 188 patients, there was a DHR to a single suspected drug. The other 110 patients had DHR histories with multiple drugs. The rate of confirmation of a drug allergy from diagnostic tests was higher in those who described a history of multiple drug allergies. Amongst the antibiotics, beta-lactam antibiotics (n = 47) were the most frequently suspected drugs. The rate of positive DPTs (n = 4; 8%) was lower in patients with suspected beta-lactam allergies than other antibiotics (p = 0.002). NSAIDs (n = 60) were the second most common group of suspected drug allergies. With regard to IgE or COX-1-mediated mechanisms, there was no statistically significant difference in DPT positivity among these NSAIDs (p = 0.414). The severity of the initial early-type DHRs were grade 1 (n = 168; 80%), grade 2 (n = 14; 7%), and grade 3 (n = 14; 7%). If the patients had redness, itching, urticaria, angioedema, dyspnea, cyanosis, desaturation, syncope, tachycardia, or hypotension during their initial DHRs, the positive diagnostic drug test rate was statistically significantly higher. However, experiencing diarrhea, nausea, and vomiting were not found to be associated with positive diagnostic drug tests. Drug allergies were confirmed with SPTs or IDTs in all patients in whom adrenaline was used during initial reactions. Conclusions: Contrary to the prevailing notion that drugs (especially beta-lactams) are the predominant cause of allergic reactions, this study demonstrated that the actual prevalence of drug allergies is, in fact, low.

Diagnostic evaluation of hypersensitivity reactions to arylpropionic acid derivatives: a descriptive observational study focusing on clinical characteristics and potential risk factors in children

BACKGROUND

Arylpropionic acid derivatives (APs) are the main triggers of nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity. Data on clinical patterns and risk factors for AP hypersensitivity in children are quite limited.

AIM

To assess the clinical characteristics and potential risk factors for proven AP hypersensitivity in children.

METHOD

Patients with a history of AP hypersensitivity were retrospectively assessed using a standardized diagnostic algorithm. Children with confirmed hypersensitivity were defined as selective responders or cross-intolerants based on the result of drug provocation tests and further categorized according to the EAACI/ENDA classification. A multivariable logistic regression analysis was performed to analyze the potential risk factors for proven AP hypersensitivity.

RESULTS

A total of 166 patients (51.2% male, median age of six years) with a history of AP hypersensitivity were included. Ibuprofen (89.2%) was the most frequently reported AP in the patients' histories. The reported hypersensitivity of 40 (22.4%) patients was confirmed by diagnostic testing: eight (13.6%) patients with a history of reaction only to APs and 32 (29.9%) patients with a history of reactions to multiple NSAIDs, including chemically unrelated NSAIDs in addition to APs. Five (12.5%) patients were classified as selective responders and 35 (87.5%) were cross-intolerants. Overall, five (12.5%) of the confirmed cases could not be categorized according to the EAACI/ENDA classification. Older age (aOR: 1.11, 95% CI 1.02-1.21, p = 0.015), chronic urticaria as an underlying disease (aOR: 2.87, 95% CI 1.09-7.54, p = 0.033) and a history of anaphylaxis (aOR: 7.84, 95% CI 1.86-33.04, p = 0.005) were related to confirmed AP hypersensitivity.

CONCLUSION

Almost a quarter of children and adolescents were confirmed to have AP hypersensitivity. Older age, the presence of chronic urticaria and a history of anaphylaxis were potential risk factors for proven AP hypersensitivity.

Assessment of pediatric patients with suspected nonsteroidal anti-inflammatory drug hypersensitivity

Background: Beta-lactam antibiotics are the most common cause of hypersensitivity reactions to medications, followed by nonsteroidal anti-inflammatory drugs (NSAID). Objective: The aim of this study was to classify children with hypersensitivity reactions to nonsteroidal anti-inflammatory drugs (NSAID-H) according to the latest updates. Methods: ENDA recommendations were used to evaluate all patients with suspected NSAID-H. Children were classified as either selective responders (SR) or cross-intolerant based on the results of the drug provocation test (DPT). Results: Sixty-seven patients with suspected NSAID-H were evaluated in this study. NSAID-H was confirmed in 20 patients (29.9%). Among the 20 patients diagnosed with NSAID-H, 15 were classified according to the 2018 EAACI/ENDA Position Paper. Twelve patients (80%) were classified as cross-intolerant and 3 (20%) as SRs. NSAID-H was confirmed in 4 of 37 patients (10.8%) ages <10 years and 16 of 30 patients (53.3%) ages >10 years (p < 0.001). Twelve patients ages >10 years were classified. Cross-intolerance was detected in nine patients (66.6%). In patients >10 years of age, NSAID-induced urticaria/angioedema (NIUA) (16.7%) was the most common type in the group with classifiable cross-intolerant. In addition, NSAID-exacerbated respiratory disease was detected in one patient. Conculsion: Ibuprofen is the most common NSAID-H drug used in children. NIUA is the most common reaction. In pediatric allergy, hypersensitivity to NSAIDs is a challenging diagnostic issue. Hypersensitivity to NSAIDs poses a challenging diagnostic issue in pediatric allergies. The oral challenge test is the main diagnostic tool; however, in clinical practice, performing multiple challenge tests is difficult.

The association between ibuprofen administration in children and the risk of developing or exacerbating asthma: a systematic review and meta-analysis

BACKGROUND

Ibuprofen is one of the most commonly used analgesic and antipyretic drugs in children. However, its potential causal role in childhood asthma pathogenesis remains uncertain. In this systematic review, we assessed the association between ibuprofen administration in children and the risk of developing or exacerbating asthma.

METHODS

We searched MEDLINE, Embase, Cochrane Library, CINAHL, Web of Science, and Scopus from inception to May 2022, with no language limits; searched relevant reviews; and performed citation searching. We included studies of any design that were primary empirical peer-reviewed publications, where ibuprofen use in children 0-18 years was reported. Screening was performed in duplicate by blinded review. In total, 24 studies met our criteria. Data were extracted according to PRISMA guidelines, and the risk of bias was assessed using RoB2 and NOS tools. Quantitative data were pooled using fixed effect models, and qualitative data were pooled using narrative synthesis. Primary outcomes were asthma or asthma-like symptoms. The results were grouped according to population (general, asthmatic, and ibuprofen-hypersensitive), comparator type (active and non-active) and follow-up duration (short- and long-term).

RESULTS

Comparing ibuprofen with active comparators, there was no evidence of a higher risk associated with ibuprofen over both the short and long term in either the general or asthmatic population. Comparing ibuprofen use with no active alternative over a short-term follow-up, ibuprofen may provide protection against asthma-like symptoms in the general population when used to ease symptoms of fever or bronchiolitis. In contrast, it may cause asthma exacerbation for those with pre-existing asthma. However, in both populations, there were no clear long-term follow-up effects.

CONCLUSIONS

Ibuprofen use in children had no elevated risk relative to active comparators. However, use in children with asthma may lead to asthma exacerbation. The results are driven by a very small number of influential studies, and research in several key clinical contexts is limited to single studies. Both clinical trials and observational studies are needed to understand the potential role of ibuprofen in childhood asthma pathogenesis.

Ibuprofen and Other Arylpropionics: The Relevance in Immediate Hypersensitivity Drug Reactions

BACKGROUND

Ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), is the most frequent medication to be involved in hypersensitivity drug reactions (HDRs). Other analgesic/anti-inflammatory drugs in the arylpropionic group are also relevant, albeit to a lesser extent. Ibuprofen is widely consumed by people of all ages, both on medical prescription and over the counter; moreover, it is an organic contaminant of surface waters and foods. While numerous drugs cause HDR, ibuprofen's underlying mechanisms are more intricate and involve both specific immunological and non-immunological mediated reactions.

SUMMARY

we concentrate on immediate responses, including urticaria with or without angioedema, anaphylaxis, and angioedema, classifying reactions according to whether they are caused by single or multiple NSAIDs and based on the mechanisms at play. Both groups may experience anaphylaxis, defined as an immediate, severe systemic reaction involving at least two organs, though the frequency and severity can vary. Following this classification, more clinical manifestations can be identified. Diagnosis is partly based on a detailed clinical history, including information about ibuprofen and/or other arylpropionic derivatives involved, the interval between drug intake and symptoms onset, clinical manifestations, number of episodes, and the patient's tolerance or response to other medications - mainly non-chemically related NSAID - both before and after reactions to ibuprofen and/or other arylpropionic drugs. A drug provocation test is frequently necessary to make a diagnosis.

KEY MESSAGE

Because ibuprofen is the most widely prescribed NSAID, it is reasonable to assume its role as the leading cause of HDR will only become more important.

Alternative Drug Safety in Children with Nonsteroidal Anti-Inflammatory Drug Hypersensitivity

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used in the pediatric age group as pain relievers, antipyretics and anti-inflammatory drugs. Since NSAIDs are used in many medical conditions, there is a need for alternative NSAIDs to be used safely in people with hypersensitivity reactions. Selective and partially selective COX-2 inhibitors and weak COX-1 inhibitors are generally used as safe alternative drugs. The aim of this study was to evaluate safe NSAIDs determined by oral provocation tests (OPTs) according to phenotypes in children with NSAID hypersensitivity reactions.

METHODS

The results of the oral provocation test performed with alternative NSAIDs (paracetamol, meloxicam, nimesulide, celecoxib) in patients followed up with the diagnosis of NSAID hypersensitivity reaction in the Pediatric Immunology and Allergy Department between January 2015 and February 2023 were evaluated retrospectively.

RESULTS

During the study period, 91 patients underwent OPTs with 109 alternative drugs 48 (52.7%) of whom were girls, with a median age of 15 years. 91 patients had a history of reactions to 117 drugs. As an alternative NSAID; OPT was performed with paracetamol in 58 patients, meloxicam in 44 patients, nimesulide in 5 patients, and celecoxib in 2 patients. Since 15 patients used paracetamol safely at home, no tests were performed with paracetamol. Reactions were observed in 3 of the 73 patients (4.1%) who underwent OPT with paracetamol and in 2 of the 44 (4.5%) who underwent OPT with meloxicam. Reactions to nimesulide were also observed in the latter 2 patients (2/5, 40%), but they appeared to tolerate celecoxib. No reaction was observed in the 2 patients who were tested with celecoxib.

CONCLUSION

Paracetamol, meloxicam, and nimesulide can be used as safe alternative drugs in most children with NSAID hypersensitivity. Selective COX-2 inhibitors should be tried as an alternative in patients who cannot tolerate them.

Evaluation of different protocols for classification of pediatric hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: Children with underlying allergic disease should be a separate subgroup

Background: Different recommendations for the classification of nonsteroidal anti-inflammatory drug hypersensitivity reactions (NSHSR) in children have been reported but a shortage still exists. Objective: The aim of the present study was to evaluate the inclusivity of two European Academy of Allergy and Clinical Immunology (EAACI) position paper classifications and to characterize the factors that underlie classification discordance in children. Methods: Patients with a history of NSHSR were evaluated with a standardized diagnostic protocol according to EAACI/ European Network for Drug Allergy (ENDA) recommendations. Children were classified and compared according to the EAACI 2013 and the pediatric EAACI/ENDA 2018 classifications. Subjects who were unclassified and those who were classified were compared. Results: Of 232 patients (median [interquartile range] age 6 years (4-11 years) with a history of NSHSR, 52 (22.4%) were confirmed with diagnostic tests. Thirty-six (69.2%) were classified as having cross-intolerance, whereas 16 patients (30.8%) were classified as selective responders. Eleven of the confirmed cases (21.2%) could not be categorized according to the 2013 EAACI classification, whereas this number was six adolescents (11.5%) when the 2018 EAACI/ENDA pediatric classification was used. Patients who were unclassified and who were all cross-intolerant were more likely to have atopic sensitization (p = 0.001) and asthma as an underlying disease (p = 0.03), higher serum eosinophil count (p = 0.022), and total immunoglobulin E levels (p = 0.007) compared with those who fit well into the classification. In multivariate regression analysis, the presence of atopic sensitization (adjusted odds ratio 20.36 [95% confidence interval, 2.14-193.48]; p = 0.009) was found to be the only significant underlying factor for an unclassified and/or blended phenotype. Conclusion: The 2013 EAACI classification resulted in a high rate of subjects who were unclassified. Despite better clinical utility, the recent pediatric EAACI/ENDA classification system still has shortcomings in terms of inclusivity for adolescents. Mostly, children with underlying allergic diseases could not be classified by the current guidelines. We propose to classify them as a separate pediatric cross-intolerance subgroup because the underlying mechanism may involve more than cyclooxygenase 1 inhibition.

Practical Approach to Hypersensitivity to Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) in Children

BACKGROUND

We aimed to assess the real-life prevalence, patient profile, and clinical presentation of drug hypersensitivity to NSAIDs in children after an incidence of an adverse event during treatment, verified by a drug challenge test.

METHODS

We included 56 children, aged 4-18 years, referred to our allergy clinic due to the incidence of adverse reaction during treatment. Skin prick tests and a drug provocation test were performed in all patients. Diagnostics for persistent urticaria were performed.

RESULTS

In 56 patients suspected of drug allergy, we proved NSAID hypersensitivity in 17 patients (30.1%). In 84.9% (n = 47) of patients, the clinical manifestations of hypersensitivity revealed angioedema and urticaria. The most common culprit drug among NSAIDs in children was ibuprofen. Thirty-one (55.4%) reactions were immediate, and 25 (44.6%) were delayed or late. Previous history of allergy was a risk factor for NSAID hypersensitivity (p = 0.001). Vitamin D deficiency in the blood serum was a risk factor for NASID hypersensitivity (OR = 5.76 (95% Cl: 1.42-23.41)).

CONCLUSIONS

Hypersensitivity to NSAIDs is a difficult diagnostic problem in pediatric allergy. The most common manifestation of hypersensitivity to ibuprofen in children is acute urticaria and angioedema. Two important problems in the differential diagnosis are cofactors such as vitamin D levels and viral infections, which require further research.

Safety and outcomes of "at-home self-provocation tests" in patients with mild nonsteroidal anti-inflammatory drug-induced urticaria/angioedema

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity is common; however, many patients do not receive an accurate diagnosis and are using unnecessary alternative drugs or have medication restrictions.

OBJECTIVE

To establish a protocol for provocation tests that can be performed safely and effectively at home to give patients an accurate diagnosis, whereas also delabeling NSAID hypersensitivity.

METHODS

We retrospectively analyzed the medical records of 147 patients with NSAID hypersensitivity. All patients had NSAID-induced urticaria/angioedema with less than 10% body surface area skin involvement. One specialist developed the protocol through history taking and chart review. If NSAID hypersensitivity was confirmed, an oral provocation test was performed to confirm the safe alternative medications (group A). If it was undetermined, an oral provocation test was performed to confirm the diagnosis and alternative medications (group B). All oral provocation tests were performed by patients in their homes according to the protocol.

RESULTS

Approximately 26% of group A patients had urticaria or angioedema symptoms with alternative drugs, whereas the remaining 74% was safe. In group B, 34% of the patients were diagnosed with having NSAID hypersensitivity. However, 61% did not respond to the culprit drug; therefore, NSAID hypersensitivity had been misdiagnosed. During this at-home self-provocation test, no severe hypersensitivity reactions occurred.

CONCLUSION

Many patients originally suspected of having NSAID hypersensitivity were confirmed to have been misdiagnosed. We successfully conducted an effective and safe at-home self-provocation test.

Drug provocation tests in children: All that glitters is not gold

A proper allergy work-up, based on the gold standard drug provocation test (DPT), usually rules out suspected drug hypersensitivity in children. These tests are generally open, given their high efficiency compared with double-blind placebo-controlled DPTs. Although their negative predictive value is excellent, no studies have calculated their positive predictive value, highly dependent on the prevalence of the disease. Most studies have found a rate of <5%-10% of true beta-lactam hypersensitivity in children. Given this low prevalence (pre-test probability), a few false-positive results can significantly reduce the estimated positive predictive value. False positives may arise from the nocebo effect during the test, including nocebo by proxy, or from observer bias, which depends on professional expertise and organizational circumstances. Some studies have found a high rate of tolerance on a second DPT in children who failed the first, but these results may be affected by the interval between the two tests, of a year or more in most cases, reflecting a loss of hypersensitivity over time. Taking into account the low rate of positive DPTs, with commonly mild reactions, we suggest confirming nonsevere positive DPTs with a second provocation performed soon after the first, especially in the case of beta-lactam antibiotics, in order to improve the diagnostic accuracy, de-label more patients, and achieve a better estimation of true drug hypersensitivity prevalence. In case of mild immediate reactions, the potential benefits of a second DPT should be carefully weighed against the risk of anaphylaxis.

Evaluation and Updated Classification of Acute Hypersensitivity Reactions to Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): NSAID-Exacerbated or -Induced Food Allergy

BACKGROUND

There are hypersensitivity reactions (HRs) to foods in which nonsteroidal anti-inflammatory drugs (NSAIDs) act as aggravating factors (NSAID-exacerbated food allergy [NEFA]) or cofactors (NSAID-induced food allergy [NIFA]), often misdiagnosed as HRs to NSAIDs. Urticarial/angioedematous and/or anaphylactic reactions to two or more chemically unrelated NSAIDs do not meet current classification criteria. However, they may be considered part of a cross-reactive type of acute HR, which is NSAID-induced urticaria/angioedema with or without respiratory or systemic symptoms of anaphylaxis.

OBJECTIVE

To evaluate patients reporting acute HRs to NSAIDs and classify them according to updated criteria.

METHODS

We prospectively studied 414 patients with suspected HRs to NSAIDs. For all whom met these criteria, NEFA/NIFA was diagnosed: (1) mild reactions to (NEFA) or tolerance of (NIFA) the suspected foods without taking NSAIDs; (2) cutaneous and/or anaphylactic reactions to the combination foods plus NSAIDs; (3) positive allergy tests to the suspected foods; and (4) negative drug challenges (DCs) with the NSAIDs involved.

RESULTS

A total of 252 patients were given the diagnosis of NSAID hypersensitivity (60.9%), 108 of whom had NSAID-induced urticaria/angioedema with or without respiratory or systemic symptoms of anaphylaxis. We excluded NSAID hypersensitivity in 162 patients (39.1%) who tolerated DCs with the suspected NSAIDs, nine of whom received a diagnosis of NEFA, and 66 of NIFA. Pru p 3 was implicated in 67 of those 75 patients who received a diagnosis of NEFA or NIFA.

CONCLUSIONS

NEFA and NIFA account for about 18% of patients reporting HRs to NSAIDs, in which Pru p 3 is the main responsible food allergen. Therefore, patients with cutaneous and/or anaphylactic reactions to NSAIDs should be carefully questioned about all foods ingested within 4 hours before or after NSAID exposure, and targeted food allergy tests should be considered in the diagnostic workup of these patients. If testing is positive, DCs with the suspected NSAIDs should also be considered.

Recent Updates in Understanding NSAID Hypersensitivity

PURPOSE OF REVIEW

To provide a review of available literature regarding nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity with an emphasis on more recent findings.

RECENT FINDINGS

Oral provocation tests with aspirin are important for diagnosis and management in adult and pediatric populations with reported NSAID hypersensitivity. Risk of cross-reactivity to COX-2 inhibitors varies by NSAID hypersensitivity phenotype. COX-2 inhibitors are tolerated in aspirin-exacerbated respiratory disease. Reported NSAID allergy is associated with a higher risk of a substance use disorder. Effective treatment of underlying chronic spontaneous urticaria can allow tolerance of NSAIDs in NSAID-exacerbated cutaneous disease. The pathophysiology, cross-reactivity, and appropriate diagnostic evaluation differ between the 5 distinct NSAID hypersensitivity phenotypes. Further research into the pathophysiology of NSAID hypersensitivity in patients with and without underlying disease is needed.

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.

Safety, Outcomes, and Recommendations for Two-Step Outpatient Nonsteroidal Anti-Inflammatory Drug Challenges

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID) outpatient challenge protocols are not standardized. They vary in clinical practice and can be time- and resource-intensive to perform.

OBJECTIVE

To investigate the safety and outcomes of two-step outpatient NSAID challenges to evaluate patients with non-aspirin-exacerbated respiratory disease (AERD)-related NSAID hypersensitivity.

METHODS

We conducted a retrospective study of patients with a history of NSAID allergy who underwent outpatient NSAID challenges under allergist supervision. Individuals with AERD were excluded. Patient demographics, NSAID reaction history, and drug challenge details and outcomes were collected.

RESULTS

A total of 249 patients (mean age, 51.6 years; 63.5% female) underwent 262 NSAID challenges. Of these, 224 challenges were negative (85.5%). Thirty challenges resulted in an immediate reaction during the challenge procedure (11.5%) and eight resulted in delayed reactions (3.1%). Three individuals with immediate reactions required treatment with intramuscular epinephrine. Factors associated with a positive NSAID challenge included a prior reaction occurring within 5 years of drug challenge (odds ratio [OR] = 3.66; 95% confidence interval [CI], 1.67-8.44), a prior immediate reaction within 3 hours of NSAID ingestion (OR = 2.45; 95% CI, 1.12-5.57), a history of cross-reactive NSAID hypersensitivity to multiple NSAIDs (OR = 2.97; 95% CI, 1.23-6.91), and the presence of comorbid chronic spontaneous urticaria (OR = 2.95; 95% CI, 1.35-6.41).

CONCLUSIONS

More than 85% of two-step non-AERD NSAID drug challenges were negative for an immediate or delayed reaction, which allowed patients to use at least one clinically indicated NSAID. Challenge reactions were generally mild. Two-step NSAID challenge protocols can be safely performed in the outpatient setting.