Hypersensitivity to aspirin: common eicosanoid alterations in urticaria and asthma

Ketorolac-induced anaphylaxis following oral administration: a case series

Background

Ketorolac is a commonly used non-steroidal anti-inflammatory drug for reducing pain and inflammation. Anaphylaxis is a medical emergency that occurs after exposure to an allergen, with a varied clinical presentation requiring prompt and appropriate measures to prevent or manage it. Although uncommon, ketorolac can cause anaphylaxis requiring immediate medical care. The authors present two cases of anaphylaxis in females induced after oral intake of ketorolac with successful outcomes.

Case presentations

The cases involve two adult women who experienced an allergic reaction to ketorolac. The first woman, aged 36, and the second woman, aged 26, on her second postpartum day, both developed similar types of symptoms like periorbital swelling, itching, and difficulty breathing after taking oral ketorolac. The second woman had a history of allergic rashes. They received immediate treatment with epinephrine, oxygen therapy, intravenous fluids, and other medications. They showed a rapid improvement and were discharged after observation.

Clinical discussion

Anaphylactic reactions to ketorolac, a commonly used pain management drug, have been reported. Symptoms include swelling, difficulty breathing, and hypotension. Treatment involves medications like epinephrine, hydrocortisone, and pheniramine. A detailed medical history, laboratory investigations, appropriate medication, oxygen therapy, and follow-up care are important in managing anaphylactic reactions, which can be life-threatening.

Conclusion

Although rare, ketorolac can cause anaphylactic reactions in patients with or without a history of drug allergy. Immediate recognition and management are essential, along with a detailed medical history and follow-up care.

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.

Chronic urticaria and the pathogenic role of mast cells

The signs and symptoms of chronic urticaria (CU) are caused by the activation and degranulation of skin mast cells (MCs). Recent studies have added to our understanding of how and why skin MCs are involved and different in CU. Also, novel and relevant mechanisms of MC activation in CU have been identified and characterized. Finally, the use of MC-targeted and MC mediator-specific treatments has helped to better define the role of the skin environment, the contribution of specific MC mediators, and the relevance of MC crosstalk with other cells in the pathogenesis of CU. Here, we review these recent findings and their impact on our understanding of CU, with a focus on chronic spontaneous urticaria (CSU). Also, we highlight open questions, issues of controversy, and unmet needs, and we suggest what studies should be performed moving forward.

Acetylsalicylic acid challenge or desensitization in sensitive patients with cardiovascular disease

The use of acetylsalicylic acid (ASA) is problematic in subjects with histories of hypersensitivity reactions (HRs) to it or with cross-reactive types of nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity. We sought to evaluate the efficacy of low-dose ASA challenge (LDAC) and desensitization to allow ASA therapy at an antiplatelet dose in patients with atherosclerotic cardiovascular disease (ASCVD) or multiple related risk factors and histories of HRs to ASA or ≥ 2 chemically unrelated NSAIDs. We studied prospectively all patients with such histories and ≥ 3 risk factors for ASCVD (group I), chronic coronary syndrome (CCS, group II), and acute coronary syndrome (ACS) with indication for ASA desensitization (group III). Patients from groups I and II underwent LDACs (cumulative dose of 110 mg), while those from group III were desensitized (cumulative dose of 100.1 mg). We evaluated 103 patients: 62 from group I, 24 from group II, and 17 from group III. Eighty-two of the 86 patients from the first two groups underwent LDACs and 2 reacted. Subsequently, 22 (27.5%) of the 80 patients with negative LDACs were administered dual antiplatelet therapy with ASA after successful percutaneous coronary interventions, thus sparing desensitizations. The remaining 4 patients with CCS and all 17 patients from group III were successfully desensitized. In this pragmatic study, LDAC proved to be a safe and reliable diagnostic tool for identifying patients with histories of HRs to ASA or ≥ 2 different NSAIDs who can tolerate ASA at antiplatelet doses. Routine LDAC is advisable in all patients at high risk for ASCVD or with CCS who report HRs to ASA or ≥ 2 NSAIDs. ASA desensitization remains a safe and effective option in patients with ACS. Study flow-chart. ASCVD atherosclerotic cardiovascular disease; CCS chronic coronary syndrome; ACS acute coronary syndrome; ASA acetylsalicylic acid; DAPT dual antiplatelet therapy; PCI percutaneous coronary intervention; NSAIDs nonsteroidal anti-inflammatory drugs; NERD NSAID-exacerbated respiratory disease; NECD NSAID-exacerbated cutaneous disease; NIUAA NSAID-induced urticaria-angioedema or anaphylaxis; SNIUAA single NSAID-induced urticaria-angioedema or anaphylaxis; SNIDHR single NSAID-induced delayed hypersensitivity reaction.

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.

Mastocytosis presenting with mast cell‐mediator release‐associated symptoms elicited by cyclo oxygenase inhibitors: prevalence, clinical, and laboratory features

Background

Nonsteroidal anti‐inflammatory drugs (NSAIDs) are frequently avoided in mastocytosis, because of a potential increased risk for drug hypersensitivity reactions (DHRs) due to inhibition of cyclo‐oxygenase (COX), subsequent depletion of prostaglandin E₂ and release of leukotrienes.

Objectives

Here, we aimed at determining the prevalence of mast cell (MC) mediator release symptoms triggered by NSAIDs in mastocytosis patients and the associated clinical and laboratory features of the disease.

Methods

Medical records from 418 adults to 223 pediatric mastocytosis patients were retrospectively reviewed. Patients were classified according to tolerance patterns to NSAIDs and other COX inhibitors (COXi) and compared for epidemiological, clinical and laboratory findings.

Results

Overall, 87% of adults and 91% of pediatric patients tolerated NSAIDs and other COXi. Among adult and pediatric patients presenting DHRs, 5% and 0% reacted to multiple NSAIDs, 4% and 0.7% were single reactors, and 3% and 8% were single reactors with known tolerance to paracetamol but unknown tolerance to other COXi, respectively. Among adults, hypersensitivity to ≥2 drugs was more frequent among females (p = 0.009), patients with prior history of anaphylaxis to triggers other than NSAIDs or other COXi and Hymenoptera venom (p = 0.009), presence of baseline flushing (p = 0.02), baseline serum tryptase ≥48 ng/ml (p = 0.005) and multilineage KIT mutation (p = 0.02). In contrast, tolerance to NSAIDs and other COXi was more frequent among males (p = 0.02), in patients with anaphylaxis caused by Hymenoptera venom (p = 0.02), among individuals who had skin lesions due to mastocytosis (p = 0.01), and in cases that had no baseline pruritus (p = 0.006). Based on these parameters, a score model was designed to stratify mastocytosis patients who have never received NSAIDs or other COXi apart from paracetamol, according to their risk of DHR.

Conclusions

Our results suggest that despite the frequency of MC mediator related symptoms elicited by NSAIDs and other COXi apart from paracetamol is increased among mastocytosis patients versus the general population, it is lower than previously estimated and associated with unique disease features. Patients that tolerated NSAIDs and other COXi following disease onset should keep using them. In turn, adults with unknown tolerance to such drugs and a positive score should be challenged with a preferential/selective COX‐2 inhibitor, while the remaining may be challenged with ibuprofen.

Effects of non-steroidal anti-inflammatory drugs and other eicosanoid pathway modifiers on antiviral and allergic responses: EAACI task force on eicosanoids consensus report in times of COVID-19

Non‐steroidal anti‐inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are among the most ubiquitously used medications in the general population. Their broad anti‐inflammatory, antipyretic, and analgesic effects are applied against symptoms of respiratory infections, including SARS‐CoV‐2, as well as in other acute and chronic inflammatory diseases that often coexist with allergy and asthma. However, the current pandemic of COVID‐19 also revealed the gaps in our understanding of their mechanism of action, selectivity, and interactions not only during viral infections and inflammation, but also in asthma exacerbations, uncontrolled allergic inflammation, and NSAIDs‐exacerbated respiratory disease (NERD). In this context, the consensus report summarizes currently available knowledge, novel discoveries, and controversies regarding the use of NSAIDs in COVID‐19, and the role of NSAIDs in asthma and viral asthma exacerbations. We also describe here novel mechanisms of action of leukotriene receptor antagonists (LTRAs), outline how to predict responses to LTRA therapy and discuss a potential role of LTRA therapy in COVID‐19 treatment. Moreover, we discuss interactions of novel T2 biologicals and other eicosanoid pathway modifiers on the horizon, such as prostaglandin D2 antagonists and cannabinoids, with eicosanoid pathways, in context of viral infections and exacerbations of asthma and allergic diseases. Finally, we identify and summarize the major knowledge gaps and unmet needs in current eicosanoid research.

Anaphylaxis to Drugs, Biological Agents, and Vaccines

Anaphylaxis is a multi-system syndrome resulting from the release of mediators from mast cells and basophils. Drugs are common causes. Anaphylaxis to certain drugs, vaccines, and biological agents present clinical challenges, and merit referral to a board-certified allergist/immunologist for further evaluation and management.

75% negative skin test results in patients with suspected hypersensitivity to beta-lactam antibiotics: Influencing factors and interpretation of test results

Background

The diagnostic approach for beta-lactam (BL) drug hypersensitivity reactions (DHR) is based on the history, clinical signs, skin tests (ST), in vitro tests, and drug provocation tests (DPT). The aim of this study was to assess the performance of an allergy workup with ST in a real-world use.

Methods

In this cross-sectional study the rate of positive ST in subjects with suspected DHR to penicillins and cephalosporins was investigated. Of special interest were correlations of ST positivity: 1) to the time intervals between index reaction and the allergic work-up, 2) time interval from drug exposure to the onset of signs, 3) pattern of manifestation in delayed DHR and involvement of test area in the index reaction, and 4) potential advantage of patch testing in delayed DHR.

Results

175 patients were included between January 2018 and April 2019 (63.4% female), 45 (25.7%) with immediate DHR manifestation and 130 with delayed DHR manifestation (74.3%). A total of 44 patients (25.1%) had a positive ST (immediate DHR 37.8% versus 20.0% in delayed DHR). ST positivity decreased in both groups after 3 years from 47.8% [95%CI 29.2-67] to 23.5% [95%CI 9.6-47.3] in immediate DHR and 23.0% [95%CI 15-4-32.9] to 12.9% [95%CI 5.1-28.9] in delayed DHR. The proportion of positive ST was higher in patients with more severe forms of delayed DHR, and in subjects with a shorter latency period of onset of symptoms after drug exposure: 0-3d: 29.5% [95%CI 19.6-41.9] vs. >3d: 11.6% [95%CI 6.0-21.2]). No sensitization was shown in delayed urticaria or angioedema. ST done outside the skin area involved during the index reaction were negative in all cases (0/38 vs. 26/84 in cases with involved area). The combination of patch test and intradermal test (IDT) revealed an additional positive result in 2/77 cases. Additional in vitro testing reduced the proportion of negative test results to 72%.

Conclusion

In most patients with negative test results, we could not clarify the cause of the BL-associated adverse events even with further investigations (including DPT). How to prevent new drug-induced adverse events in such patients has hardly been investigated yet. Corresponding cohort studies could improve the data situation.

Pharmacogenomics of Hypersensitivity to Non-steroidal Anti-inflammatory Drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are extensively prescribed in daily clinical practice. NSAIDs are the main cause of drug hypersensitivity reactions all over the world. The inhibition of cyclooxygenase enzymes by NSAIDs can perpetuate arachidonic acid metabolism, shunting to the 5-lipoxygenase pathway and its downstream inflammatory process. Clinical phenotypes of NSAID hypersensitivity are diverse and can be classified into cross-reactive or selective responses. Efforts have been made to understand pathogenic mechanisms, in which, genetic and epigenetic backgrounds are implicated in various processes of NSAID-induced hypersensitivity reactions. Although there were some similarities among patients, several genetic polymorphisms are distinct in those exhibiting respiratory or cutaneous symptoms. Moreover, the expression levels, as well as the methylation status of genes related to immune responses were demonstrated to be involved in NSAID-induced hypersensitivity reactions. There is still a lack of data on delayed type reactions. Further studies with a larger sample size, which integrate different genetic pathways, can help overcome current limitations of gen etic/epigenetic studies, and provide valuable information on NSAID hypersensitivity reactions.

Divergent PGD2 and leukotriene C4 metabolite excretion following aspirin therapy: Ten patients with systemic mastocytosis

Aspirin-exacerbated respiratory disease and some cases of chronic idiopathic urticaria are disorders in which increased baseline urinary excretion of leukotriene(LT)E4 further increases following aspirin administration. Increased urinary excretion of the metabolites of prostaglandin D2, 11β-prostaglandin(PG)F2α and (2,3-dinor)-11β-PGF2α, have been documented in systemic mastocytosis (SM) and in mast cell activation syndrome (MCAS). Symptoms due to increased baseline and/or episodic release of PGD2 can be prevented with aspirin, an inhibitor of cyclooxygenase (COX)1 and COX2. Here by retrospective chart review we discovered 8 of 10 patients with SM in whom normalization of an elevated urinary (2,3-dinor)-11β-PGF2α occurred with aspirin therapy also had a parallel increased excretion of LTE4 by an average of nearly 13-fold. How widespread this phenomenon occurs in SM is unknown; however, this occurrence needs to be considered when interpreting changes in these urinary mast cell mediator metabolites during aspirin therapy.

Platelet-Adherent Leukocytes Associated With Cutaneous Cross-Reactive Hypersensitivity to Nonsteroidal Anti-Inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most highly consumed drugs worldwide and the main triggers of drug hypersensitivity reactions. The most frequent reaction, named cross-reactive NSAID-hypersensitivity, is due to the pharmacological activity of these drugs by blocking the cyclooxygenase-1 enzyme. Such inhibition leads to cysteinyl-leukotriene synthesis, mainly LTE4, which are responsible for the reaction. Although the complete molecular picture of the underlying mechanisms remains elusive, the participation of platelet-adherent leukocytes (CD61⁺) and integrins have been described for NSAID-exacerbated respiratory disease (NERD). However, there is a lack of information concerning NSAID-induced urticaria/angioedema (NIUA), by far the most frequent clinical phenotype. Here we have evaluated the potential role of CD61⁺ leukocytes and integrins (CD18, CD11a, CD11b, and CD11c) in patients with NIUA, and included the other two phenotypes with cutaneous involvement, NSAID-exacerbated cutaneous disease (NECD) and blended reactions (simultaneous skin and airways involvement). A group NSAID-tolerant individuals was also included. During the acute phase of the reaction, the three clinical phenotypes showed increased frequencies of CD61⁺ neutrophils, eosinophils, and monocytes compared to controls, which correlated with urinary LTE4 levels. However, no correlation was found between these variables at basal state. Furthermore, increased expressions of CD18 and CD11a were found in the three CD61⁺ leukocytes subsets in NIUA, NECD and blended reactions during the acute phase when compared with CD61^-leukocyte subpopulations. During the acute phase, CD61⁺ neutrophils, eosinophils and monocytes showed increased CD18 and CD11a expression when compared with CD61⁺ leukocytes at basal state. No differences were found when comparing controls and CD61⁺ leukocytes at basal state. Our results support the participation of platelet-adherent leukocytes and integrins in cutaneous cross-hypersensitivity to NSAIDs and provide a link between these cells and arachidonic acid metabolism. Our findings also suggest that these reactions do not involve a systemic imbalance in the frequency of CD61⁺ cells/integrin expression or levels of LTE4, which represents a substantial difference to NERD. Although further studies are needed, our results shed light on the molecular basis of cutaneous cross-reactive NSAID-hypersensitivity, providing potential targets for therapy through the inhibition of platelet-leukocyte interactions.

Ibuprofen-induced localized frontal and temporal forehead swellings: A rare case report

Ibuprofen, nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), is one of the most commonly prescribed analgesics for managing musculoskeletal, orofacial, and postoperative pain after periodontal therapy. Although considered as one of the safest analgesic agents, the onset of adverse drug reactions after ibuprofen intake has been recently observed. The present report aims to highlight the development of localized swellings in the temporal and frontal forehead following intake of 200 mg of ibuprofen after routine oral prophylaxis. This is the first case report to document the development of an adverse drug reaction with ibuprofen in a patient following a routine dental procedure. The article also aim to comprehensively describe the most appropriate and effective method to diagnose, manage, and prevent NSAIDs-induced adverse drug reactions in routine dental practice.

Progress in understanding hypersensitivity reactions to nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs), the medications most commonly used for treating pain and inflammation, are the main triggers of drug hypersensitivity reactions. The latest classification of NSAIDs hypersensitivity by the European Academy of Allergy and Clinical Immunology (EAACI) differentiates between cross-hypersensitivity reactions (CRs), associated with COX-1 inhibition, and selective reactions, associated with immunological mechanisms. Three phenotypes fill into the first group: NSAIDs-exacerbated respiratory disease, NSAIDs-exacerbated cutaneous disease and NSAIDs-induced urticaria/angioedema. Two phenotypes fill into the second one: single-NSAID-induced urticaria/angioedema/anaphylaxis and single-NSAID-induced delayed reactions. Diagnosis of NSAIDs hypersensitivity is hampered by different factors, including the lack of validated in vitro biomarkers and the uselessness of skin tests. The advances achieved over recent years recommend a re-evaluation of the EAACI classification, as it does not consider other phenotypes such as blended reactions (coexistence of cutaneous and respiratory symptoms) or food-dependent NSAID-induced anaphylaxis. In addition, it does not regard the natural evolution of phenotypes and their potential interconversion, the development of tolerance over time or the role of atopy. Here, we address these topics. A state of the art on the underlying mechanisms and on the approaches for biomarkers discovery is also provided, including genetic studies and available information on transcriptomics and metabolomics.

NSAID-induced reactions: classification, prevalence, impact, and management strategies

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the leading cause of hypersensitivity drug reactions. The different chemical structures, cyclooxygenase 1 (COX-1) and/or COX-2 inhibitors, are taken at all ages and some can be easily obtained over the counter. Vasoactive inflammatory mediators like histamine and leukotriene metabolites can produce local/systemic effects. Responders can be selective (SR), IgE or T-cell mediated, or cross-intolerant (CI). Inhibition of the COX pathway is the common mechanism in CI, with the skin being the most frequent organ involved, followed by the lung and/or the nose. An important number of cases have skin and respiratory involvement, with systemic manifestations ranging from mild to severe anaphylaxis. Among SR, this is the most frequent entity, often being severe. Recent years have seen an increase in reactions involving the skin, with many cases having urticaria and/or angioedema in the absence of chronic urticaria. Aspirin, the classical drug involved, has now been replaced by other NSAIDs, with ibuprofen being the universal culprit. For CI, no in vivo/in vitro diagnostic methods exist and controlled administration is the only option unless the cases evaluated report repetitive and consistent episodes with different NSAIDs. In SR, skin testing (patch and intradermal) with 24-48 reading can be useful, mainly for delayed T-cell responses. Acetyl salicylic acid (ASA) is the test drug to establish the diagnosis and confirm/exclude CI by controlled administration. Desensitization to ASA has been extensively used in respiratory cases though it can also be applied in those cases where it is required.

Eicosanoid mediator profiles in different phenotypes of nonsteroidal anti-inflammatory drug-induced urticaria

BACKGROUND

The role of arachidonic acid metabolites in NSAID-induced hypersensitivity has been studied in depth for NSAID-exacerbated respiratory disease (NERD) and NSAID-exacerbated cutaneous disease (NECD). However, no information is available for NSAID-induced urticarial/angioedema (NIUA), despite it being the most frequent clinical entity induced by NSAID hypersensitivity. We evaluated changes in leukotriene and prostaglandin metabolites for NIUA patients, using patients with NECD and single-NSAID-induced urticaria/angioedema or anaphylaxis (SNIUAA) for comparison.

METHODS

Urine samples were taken from patients with confirmed NSAID-induced urticaria and healthy controls, at baseline and at various time intervals after ASA administration. Eicosanoid measurement was performed using high-performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

RESULTS

No differences were found between groups at baseline. Following ASA administration, LTE4 and 9α,11β-PGF2 levels were increased in both NIUA and NECD patients compared to baseline, rising initially, before decreasing toward initial levels. In addition, the levels of these metabolites were higher in NIUA and NECD when compared with the SNIUAA and control groups after ASA administration. No changes were found with respect to baseline values for SNIUAA and control groups.

CONCLUSIONS

We present for the first time data regarding the role of COX-1 inhibition in NIUA. Patients with this entity show a similar pattern eicosanoid levels following ASA challenge to those with NECD. Further studies will help ascertain the cell populations involved and the underlying molecular mechanisms.

Characteristics of NSAID-induced hypersensitivity reactions in childhood

Non-steroidal anti-inflammatory drugs (NSAIDs) are available as over-the-counter drugs, and they are commonly used in children for their antipyretic, analgesic, and anti-inflammatory effects. NSAIDs are among the most frequently reported drugs associated with hypersensitivity reactions and even with anaphylaxis. A complete evaluation of the patients based on reported clinical manifestations, timing of the reaction, the presence of underlying disease, and reactions to other NSAIDs allows clinicians to stratify children with a history of reaction to NSAIDs. Although NSAID-induced hypersensitivity reactions have mainly been investigated in adults, recent studies have aimed to explore their epidemiology in the pediatric population. This review will cover the current understanding of clinical manifestations, the risk factors, and the different phenotypes of NSAID-induced hypersensitivity reactions with a comprehensive overview of the epidemiologic data from past to present and the practical approach to the management of NSAID hypersensitivity in children and adolescents.

[NSAID urticaria: Similar management to acute urticaria]

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most common providers of immediate hypersensitivity reactions. Among these reactions, isolated acute urticaria is the most common clinical feature with a non-allergic origin. It is a pharmacological side effect resulting from the alteration of arachidonic acid metabolism induced by NSAIDs. Diagnosis of this acute urticaria is clinical, requiring no allergy testing. Currently, the recommended therapeutic management of NSAID urticaria is the avoidance of all NSAID with COX-1 inhibitor activity (even if when reintroduced, they are most often well tolerated) and the use of selective COX-2 inhibitors. This review focuses on urticaria reactions to NSAIDs, which are simple to manage.

Gene Polymorphism of Aspirin-Induced Urticaria in Children With Kawasaki Disease

Objective: To investigate the distribution of the single nucleotide polymorphism (SNP) of LTC4S A-444C in children with Kawasaki disease in northern China and determine whether LTC4S A-444C SNP is associated with aspirin-induced urticaria (AIU). Methods: The clinical data of children with Kawasaki disease hospitalized in our center from April 2015 to November 2017 were collected, and fluorescence in situ hybridization was used to detect the LTC4S A-444C. According to the genotype, the subjects were divided into three groups: AA genotypes, AC genotypes, and CC genotypes. The incidence of AIU in the three groups was calculated and the relationship between LTC4S A-444C SNP and AIU was analyzed. Results: (1) A total of 574 children with Kawasaki disease were enrolled in the study. The allele frequencies for A, C were 980 (85.4%), 168 (14.6%). (2) Twenty-five cases of AIU in AA genotypes, with a positive rate of 6%, 11 cases of AIU in AC genotypes, with a positive rate of 7.5%, 2 cases of AIU in CC genotypes, with a positive rate of 18.2%. CC genotypes had higher incidence of AIU than that of AA and AC genotypes. However, there was no significant difference among the three groups (P > 0.05). Conclusion: The proportion of CC genotypes of LTC4S A-444C in children with Kawasaki disease in northern China is lower than that of AA genotypes and AC genotypes, and the incidence of AIU of CC genotypes is higher than that of AC genotypes and AA genotypes.

Evaluating and managing chronic idiopathic urticaria in adults

Chronic idiopathic urticaria (CIU), also known as chronic spontaneous urticaria, is characterized by the presence of hives on most days of the week, for 6 weeks or longer, and without an identifiable or consistent cause. Evaluation is clinical and based on the presence of episodic urticarial lesions. Although patients are subject to overtesting during the diagnosis of CIU, guidelines suggest starting with three basic laboratory tests. Treatment is a stepwise approach, involving second-generation antihistamines, histamine2 antagonists, leukotriene receptor antagonists, first-generation antihistamines, and potent antihistamines. Refractory CIU requires adding alternative agents such as omalizumab, anti-inflammatory agents, and immunosuppressants.

Hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: an update on pharmacogenetics studies

Nonsteroidal anti-inflammatory drugs are the medications most frequently involved in hypersensitivity reactions to drugs. These can be induced by specific immunological and nonimmunological mechanisms, being the latter the most frequent. The nonimmunological mechanism is related to an imbalance of inflammatory mediators, which is aggravated by the cyclooxygenase inhibition. Genetic studies suggest that multiples genes and additional mechanisms might be involved. The proposals of this review is summarize the contribution of variations in genes involved in the arachidonic acid, inflammatory and immune pathways as well as the recent genome-wide association studies findings related to cross-intolerant nonsteroidal anti-inflammatory drugs hypersensitivity reactions. In addition, using integration of different genetic studies, we propose new target genes. This will help to understand the underlying mechanism of these reactions.

EAACI/ENDA Position Paper: Diagnosis and management of hypersensitivity reactions to non-steroidal anti-inflammatory drugs (NSAIDs) in children and adolescents

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used in the pediatric population as antipyretics/analgesics and anti-inflammatory medications. Hypersensitivity (HS) reactions to NSAID in this age group, while similar to adults, have unique diagnostic and management issues. Although slowly accumulating, published data in this age group are still relatively rare and lacking a unifying consensus. This work is a summary of current knowledge and consensus recommendations utilizing both published data and expert opinion from the European Network of Drug Allergy (ENDA) and the Drug Hypersensitivity interest group in the European Academy of Allergy and Clinical Immunology (EAACI). This position paper summarizes diagnostic and management guidelines for children and adolescents with NSAIDs hypersensitivity.

Aspirin challenge and desensitization: how, when and why

PURPOSE OF REVIEW

To investigate the current approach to aspirin challenge (drug provocation) and/or desensitization in patients with histories of hypersensitivity reactions to it, particularly in those with cardiovascular diseases.

RECENT FINDINGS

The literature indicates that patients with coronary artery disease (CAD), including those with an acute coronary syndrome, may safely undergo low-dose aspirin challenge and/or desensitization. Recently, flowcharts regarding challenge/desensitization procedures with aspirin in patients with CAD and histories of aspirin hypersensitivity reactions have become available. Aspirin desensitization and continuous aspirin therapy constitute an effective option in patients with nonsteroidal anti-inflammatory drug-exacerbated respiratory diseases (NERD) who have suboptimally controlled asthma or rhinosinusitis, or require multiple revision polypectomies.

SUMMARY

The use of aspirin has proven to reduce morbidity and mortality associated with CAD. There is a general consensus on aspirin's effectiveness in secondary prevention of CAD. Therefore, aspirin desensitization is necessary in patients with CAD and histories of hypersensitivity reactions to it. The effectiveness of aspirin desensitization and continuous therapy in patients with NERD has been shown in numerous studies. However, shared selection criteria of candidates for aspirin challenge/desensitization procedures, and simple and homogeneous protocols are necessary. Moreover, preventive safety measures are still needed in order to reduce the potential risks of these procedures.

Practical approach to the treatment of NSAID hypersensitivity

INTRODUCTION

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most frequently involved in drug hypersensitivity reactions (DHR). NSAIDs are prescribed for different processes and some NSAIDs can be obtained over the counter. Areas covered: We analyse the practical approaches for managing and treating NSAID-DHR considering the five major groups of entities recognised, divided into two categories: those responding to strong COX-1 inhibitors and possibly weak COX-1 or selective COX-2 inhibitors named cross-intolerant (CI), and those induced by a single drug or drug group with good tolerance to strong COX-1 inhibitors, known as allergic reactions (SR). An analysis of the recent literature indicates that two approaches can be followed for CI: to give acetyl salicylic acid to confirm NSAID hypersensitivity or to give alternative drugs to provide a solution for the treatment of pain, fever, inflammation or other conditions. Desensitisation approaches have been undertaken, but mainly for CI cases with respiratory airway involvement and they are very rarely used for CI with cutaneous involvement or SR. Expert commentary: DHR to NSAIDs are now recognised as one of the most important problems in the evaluation and management of drug allergy. Because no diagnostic tests exist, important resources are needed to evaluate these patients.

Polymorphism of IL10, IL4, CTLA4, and DAO Genes in Cross-Reactive Nonsteroidal Anti-inflammatory Drug Hypersensitivity

Our aim was to evaluate genetic polymorphism of molecules involved in immunoregulatory/allergic processes in patients who presented with cutaneous hypersensitivity caused by chemically unrelated nonsteroidal anti-inflammatory drugs. Polymorphisms at IL10 (-1082 G>A), IL4 (-589 C>T), CTLA4 (+49A>G), and DAO (+8956 C>G) genes were studied in 55 cases and 97 controls by the polymerase chain reaction-restriction fragment length polymorphism technique. With regard to the polymorphism at IL10 -1082, higher frequencies of the AG genotype (57% vs 39%) and G allele carriers (70% vs 48%) were found among the patients, indicating a risk effect (odds ratio [OR] = 2.56 and P = .01 for AG genotype and OR = 2.52; P = .01 for AG/GG). For the CTLA4 +49 A/G single-nucleotide polymorphism (SNP), AG genotype (31.0%) (P = .02) and G carrier (54.0%) (P = .05) frequencies were found to be significantly lower in the patient group compared with the control group (51.0% and 69.0%, respectively). The SNP DAO +8956 C>G was associated with a strong protective effect, with OR values of 0.83 for CG and 0.11 for GG genotype (P = .04 for the codominant model), suggesting an allele dose effect. The combination of IL10 and DAO SNPs in a multivariate model did not alter the OR values, suggesting independent effects for both SNPs. The results are striking. In conclusion, these results suggest that polymorphisms in regulatory targets of the immune response and in DAO gene could modulate an individual's susceptibility to nonsteroidal anti-inflammatory drug hypersensitivity reactions. Further studies will be necessary to complement our results.

Drug Hypersensitivity and Desensitizations: Mechanisms and New Approaches

Drug hypersensitivity reactions (HSRs) are increasing in the 21st Century with the ever expanding availability of new therapeutic agents. Patients with cancer, chronic inflammatory diseases, cystic fibrosis, or diabetes can become allergic to their first line therapy after repeated exposures or through cross reactivity with environmental allergens. Avoidance of the offending allergenic drug may impact disease management, quality of life, and life expectancy. Precision medicine provides new tools for the understanding and management of hypersensitivity reactions (HSRs), as well as a personalized treatment approach for IgE (Immunoglobuline E) and non-IgE mediated HSRs with drug desensitization (DS). DS induces a temporary hyporesponsive state by incremental escalation of sub-optimal doses of the offending drug. In vitro models have shown evidence that IgE desensitization is an antigen-specific process which blocks calcium flux, impacts antigen/IgE/FcεRI complex internalization and prevents the acute and late phase reactions as well as mast cell mediator release. Through a "bench to bedside" approach, in vitro desensitization models help elucidate the molecular pathways involved in DS, providing new insights to improved desensitization protocols for all patients. The aim of this review is to summarize up to date information on the drug HSRs, the IgE mediated mechanisms of desensitization, and their clinical applications.

Copy number variation in ALOX5 and PTGER1 is associated with NSAIDs-induced urticaria and/or angioedema

OBJECTIVE

Cross-intolerance to NSAIDs is a class of drug hypersensitivity reaction, of which NSAIDs-induced urticaria and/or angioedema (NIUA) are the most frequent clinical entities. They are considered to involve dysregulation of the arachidonic acid pathway; however, this mechanism has not been confirmed for NIUA. In this work, we assessed copy number variations (CNVs) in eight of the main genes involved in the arachidonic acid pathway and their possible genetic association with NIUA.

MATERIALS AND METHODS

CNVs in ALOX5, LTC4S, PTGS1, PTGS2, PTGER1, PTGER2, PTGER3, and PTGER4 were analyzed using TaqMan copy number assays. Genotyping was carried out by real-time quantitative PCR. Individual genotypes were assigned using the CopyCaller Software. Statistical analysis was carried out using GraphPad prism 5, PLINK, EPIDAT, and R version 3.1.2.

RESULTS AND CONCLUSION

A total of 151 cases and 139 controls were analyzed during the discovery phase and 148 cases and 140 controls were used for replication. CNVs in open reading frames were found for ALOX5, PTGER1, PTGER3, and PTGER4. Statistically significant differences in the CNV frequency between NIUA and controls were found for ALOX5 (Pc=0.017) and PTGER1 (Pc=1.22E-04). This study represents the first analysis showing an association between CNVs in exonic regions of ALOX5 and PTGER1 and NIUA. This suggests a role of CNVs in this pathology that should be explored further.

Clinical approach on challenge and desensitization procedures with aspirin in patients with ischemic heart disease and nonsteroidal anti-inflammatory drug hypersensitivity

BACKGROUND

Hypersensitivity to acetylsalicylic acid (ASA) constitutes a serious problem for subjects with coronary artery disease. In such subjects, physicians have to choose the more appropriate procedure between challenge and desensitization. As the literature on this issue is sparse, this study aimed to establish in these subjects clinical criteria for eligibility for an ASA challenge and/or desensitization.

METHODS

Collection and analysis of data on ASA challenges and desensitizations from 10 allergy centers, as well as consensus among the related physicians and an expert panel.

RESULTS

Altogether, 310 subjects were assessed; 217 had histories of urticaria/angioedema, 50 of anaphylaxis, 26 of nonimmediate cutaneous eruptions, and 17 of bronchospasm related to ASA/nonsteroidal anti-inflammatory drugs (NSAID) intake. Specifically, 119 subjects had index reactions to ASA doses lower than 300 mg. Of the 310 subjects, 138 had an acute coronary syndrome (ACS), 101 of whom underwent desensitizations, whereas 172 suffered from a chronic ischemic heart disease (CIHD), 126 of whom underwent challenges. Overall, 163 subjects underwent challenges and 147 subjects underwent desensitizations; 86 of the latter had index reactions to ASA doses of 300 mg or less. Ten subjects reacted to challenges, seven at doses up to 500 mg, three at a cumulative dose of 110 mg. The desensitization failure rate was 1.4%.

CONCLUSIONS

In patients with stable CIHD and histories of nonsevere hypersensitivity reactions to ASA/NSAIDs, an ASA challenge is advisable. Patients with an ACS and histories of hypersensitivity reactions to ASA, especially following doses lower than 100 mg, should directly undergo desensitization.

Emerging concepts: mast cell involvement in allergic diseases

In a process known as overt degranulation, mast cells can release all at once a diverse array of products that are preformed and present within cytoplasmic granules. This occurs typically within seconds of stimulation by environmental factors and allergens. These potent, preformed mediators (ie, histamine, heparin, serotonin, and serine proteases) are responsible for the acute symptoms experienced in allergic conditions such as allergic conjunctivitis, allergic rhinitis, allergy-induced asthma, urticaria, and anaphylaxis. Yet, there is reason to believe that the actions of mast cells are important when they are not degranulating. Mast cells release preformed mediators and inflammatory cytokines for periods after degranulation and even without degranulating at all. Mast cells are consistently seen at sites of chronic inflammation, including nonallergic inflammation, where they have the ability to temper inflammatory processes and shape tissue morphology. Mast cells can trigger actions and chemotaxis in other important immune cells (eg, eosinophils and the newly discovered type 2 innate lymphocytes) that then make their own contributions to inflammation and disease. In this review, we will discuss the many known and theorized contributions of mast cells to allergic diseases, focusing on several prototypical allergic respiratory and skin conditions: asthma, chronic rhinosinusitis, aspirin-exacerbated respiratory disease, allergic conjunctivitis, atopic dermatitis, and some of the more common medication hypersensitivity reactions. We discuss traditionally accepted roles that mast cells play in the pathogenesis of each of these conditions, but we also delve into new areas of discovery and research that challenge traditionally accepted paradigms.

Basophil Reactivity as Biomarker in Immediate Drug Hypersensitivity Reactions-Potential and Limitations

Immediate drug hypersensitivity reactions (DHRs) resemble typical immunoglobulin E (IgE)-mediated symptoms. Clinical manifestations range from local skin reactions, gastrointestinal and/or respiratory symptoms to severe systemic involvement with potential fatal outcome. Depending on the substance group of the eliciting drug the correct diagnosis is a major challenge. Skin testing and in vitro diagnostics are often unreliable and not reproducible. The involvement of drug-specific IgE is questionable in many cases. The culprit substance (parent drug or metabolite) and potential cross-reacting compounds are difficult to identify, patient history and drug provocation testing often remain the only means for diagnosis. Hence, several groups proposed basophil activation test (BAT) for the diagnosis of immediate DHRs as basophils are well-known effector cells in allergic reactions. However, the usefulness of BAT in immediate DHRs is highly variable and dependent on the drug itself plus its capacity to spontaneously conjugate to serum proteins. Stimulation with pure solutions of the parent drug or metabolites thereof vs. drug-protein conjugates may influence sensitivity and specificity of the test. We thus, reviewed the available literature about the use of BAT for diagnosing immediate DHRs against drug classes such as antibiotics, radio contrast media, neuromuscular blocking agents, non-steroidal anti-inflammatory drugs, and biologicals. Influencing factors like the selection of stimulants or of the identification and activation markers, the stimulation protocol, gating strategies, and cut-off definition are addressed in this overview on BAT performance. The overall aim is to evaluate the suitability of BAT as biomarker for the diagnosis of immediate drug-induced hypersensitivity reactions.

Use of nonsteroidal anti-inflammatory drugs in patients with aspirin hypersensitivity : safety of cyclo-oxygenase-2 inhibitors

This article provides information on the pathogenesis of aspirin hypersensitivity, cross-sensitivity, and cross-tolerance of different NSAIDs in patients with respiratory types of reactions. Hypersensitivity to aspirin may affect 5-20% of patients with chronic asthma and an unknown fraction of patients with chronic urticaria-angioedema. These patients develop cross-reactions to other, chemically non-related, NSAIDs with strong inhibitory activity towards cyclo-oxygenase (COX)-1 (e.g. indomethacin, naproxen, ketoprofen). Avoidance of aspirin and all cross-reacting NSAIDs as well as education of patients are crucial. As an alternative antipyretic or analgesic drug, aspirin-sensitive asthmatic patients may take acetaminophen (paracetamol) in low or moderate doses (<1000mg). Preferential COX-2 inhibitors (nimesulide, meloxicam) are tolerated by the majority but not all hypersensitive patients. Selective COX-2 inhibitors (celecoxib and rofecoxib [withdrawn from the market]) are well tolerated by almost all aspirin-sensitive asthmatic patients. In patients with coronary artery disease requiring treatment with aspirin, desensitization to aspirin may be an alternative approach. Thus, for the majority of patients with asthma and hypersensitivity to aspirin or other NSAIDs, an alternative anti-inflammatory drug can be found. However, in each individual case physicians must consider the choice of an alternative NSAID carefully.

Genetic basis of hypersensitivity reactions to nonsteroidal anti-inflammatory drugs

PURPOSE OF REVIEW

NSAIDs are the main triggers of hypersensitivity reactions to drugs. However, the full genetic and molecular basis of these reactions has yet to be uncovered. In this article, we have summarized research from recent years into the effects of genetic variants on the different clinical entities induced by NSAID hypersensitivity, focusing on prostaglandin and leukotriene-related genes as well as others beyond the arachidonic acid pathway.

RECENT FINDINGS

We introduce recent contributions of high-throughput approaches including genome-wide association studies as well as available information from epigenetics and next-generation sequencing. Finally, we give our thoughts on future directions in this field, including the scope for bioinformatics and systems biology and the need for clear patient phenotyping.

SUMMARY

The full genetic and molecular basis of clinical entities induced by NSAIDs hypersensitivity has yet to be uncovered, and despite commendable efforts over recent years, no clinically proven genetic markers currently exist for these disorders. It is clear that we will continue to find more about these reactions in the coming years, concurrently with improvements in technology and experimental techniques, and a precise definition of different phenotypes.

Pharmacogenomics of hypertension and heart disease

Heart disease is a leading cause of death in the United States, and hypertension is a predominant risk factor. Thus, effective blood pressure control is important to prevent adverse sequelae of hypertension, including heart failure, coronary artery disease, atrial fibrillation, and ischemic stroke. Over half of Americans have uncontrolled blood pressure, which may in part be explained by interpatient variability in drug response secondary to genetic polymorphism. As such, pharmacogenetic testing may be a supplementary tool to guide treatment. This review highlights the pharmacogenetics of antihypertensive response and response to drugs that treat adverse hypertension-related sequelae, particularly coronary artery disease and atrial fibrillation. While pharmacogenetic evidence may be more robust for the latter with respect to clinical implementation, there is increasing evidence of genetic variants that may help predict antihypertensive response. However, additional research and validation are needed before clinical implementation guidelines for antihypertensive therapy can become a reality.

Approaches to the diagnosis and management of patients with a history of nonsteroidal anti-inflammatory drug-related urticaria and angioedema

Nonsteroidal anti-inflammatory drug (NSAID)-induced urticarial and angioedema reactions are among the most commonly encountered drug hypersensitivity reactions in clinical practice. Three major clinical phenotypes of NSAID-induced acute skin reactions manifesting with angioedema, urticaria, or both have been distinguished: NSAID-exacerbated cutaneous disease, nonsteroidal anti-inflammatory drug-induced urticaria/angioedema (NIUA), and single NSAID-induced urticaria and angioedema. In some patients clinical history alone might be sufficient to establish the diagnosis of a specific type of NSAID hypersensitivity, whereas in other cases oral provocation challenges are necessary to confirm the diagnosis. Moreover, classification of the type of cutaneous reaction is critical for proper management. For example, in patients with single NSAID-induced reactions, chemically nonrelated COX-1 inhibitors can be safely used. However, there is cross-reactivity between the NSAIDs in patients with NSAID-exacerbated cutaneous disease and NIUA, and thus only use of selective COX-2 inhibitors can replace the culprit drug if the chronic treatment is necessary, although aspirin desensitization will allow for chronic treatment with NSAIDs in some patients with NIUA. In this review we present a practical clinical approach to the patient with NSAID-induced urticaria and angioedema.

Systems biology approaches to enhance our understanding of drug hypersensitivity reactions

Hypersensitivity drug reactions (HDRs) encompass a wide spectrum of unpredictable clinical entities. They represent an important health problem, affecting people of all ages, and lead to a large strain on the public health system. Here, we summarize experiments that use high-throughput genomics technologies to investigate HDRs. We also introduce the field of systems biology as a relatively recent discipline concerned with the integration and analysis of high-throughput data sets such as DNA microarrays and next-generation sequencing data. We describe previous studies that have applied systems biology techniques to related fields such as allergy and asthma. Finally, we present a number of potential applications of systems biology to the study of HDRs, in order to make the reader aware of the types of analyses that can be performed and the insights that can be gained through their application.

Seven steps to the diagnosis of NSAIDs hypersensitivity: how to apply a new classification in real practice?

Frequent use of non-steroidal anti-inflammatory drugs (NSAIDs) has been paralleled by increasing occurrence of adverse reactions, which vary from mild local skin rashes or gastric irritation to severe, generalized symptoms and even life-threatening anaphylaxis. NSAID-induced hypersensitivity reactions may involve both immunological and non-immunological mechanisms and should be differentiated from type A adverse reactions. Clinical diagnosis and effective management of a hypersensitive patient cannot be achieved without identifying the underlying mechanism. In this review, we discuss the current classification of NSAID-induced adverse reactions and propose a practical diagnostic algorithm that involves 7 steps leading to the determination of the type of NSAID-induced hypersensitivity and allows for proper patient management.

Challenge-proven aspirin hypersensitivity in children with chronic spontaneous urticaria

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID) exacerbated cutaneous disease is defined as the exacerbation of wheals and/or angioedema in patients with a history of chronic spontaneous urticaria (CSU). The objective of this study was to define 'aspirin-hypersensitive' children and adolescents in a clearly defined group of patients with CSU and to describe their clinical features.

METHODS

Eighty-one children with a history of CSU were enrolled over a 3-year period. The daily or almost daily (>4 days a week) presence of urticaria was defined as 'chronic persistent urticaria' (CPU), while the presence of urticaria for 2-4 days a week was defined as 'chronic recurrent urticaria' (CRU). Single-blind, placebo-controlled provocation tests (SBPCPTs) with aspirin were performed for children with CSU.

RESULTS

Patients with CRU had a longer duration of cutaneous symptoms [1.6 (0.5-4) vs 0.6 (0.3-1.5) years], and stress was less frequently experienced as an eliciting factor in patients with CRU compared with the patients with CPU (P < 0.016, P = 0.024, respectively). SBPCPTs with aspirin revealed that 14 of 58 patients (24%) with CPU and one of 10 patients with CRU (10%) were aspirin hypersensitive. Aspirin hypersensitivity rate was 26.5% in patients <12 years of age. All of the 15 aspirin-hypersensitive patients (aged between 6.6 and 17.4 years), except for three, experienced an unequivocal angioedema of the lips as a positive reaction in SBPCPT.

CONCLUSIONS

Nearly a quarter of children and adolescents with CSU were hypersensitive to aspirin. For children with chronic urticaria, determination of NSAID hypersensitivity in a well-controlled clinical setting will help to avoid severe drug hypersensitivity reactions.

Unravelling adverse reactions to NSAIDs using systems biology

We introduce the reader to systems biology, using adverse drug reactions (ADRs), specifically hypersensitivity reactions to multiple non-steroidal anti-inflammatory drugs (NSAIDs), as a model. To disentangle the different processes that contribute to these reactions - from drug intake to the appearance of symptoms - it will be necessary to create high-throughput datasets. Just as crucial will be the use of systems biology to integrate and make sense of them. We review previous work using systems biology to study related pathologies such as asthma/allergy, and NSAID metabolism. We show examples of their application to NSAIDs-hypersensitivity using current datasets. We describe breakthroughs in high-throughput technology and speculate on their use to improve our understanding of this and other drug-induced pathologies.

Genotype- and phenotype-directed antiplatelet therapy selection in patients with acute coronary syndromes

Although dual antiplatelet therapy (DAPT) has been a standard treatment in patients with acute coronary syndrome (ACS) for over a decade, only recently have therapeutic options beyond aspirin and clopidogrel become available. Additional treatment options are particularly useful because of the documented history of variability in antiplatelet response. This article reviews the current treatment options for DAPT in ACS, and reviews both genotype- and phenotype-guided methods for determining optimal antiplatelet therapy for patients with ACS. Additionally, recommendations from current guidelines as well as expert commentary are provided for the use of available testing methods to determine optimal DAPT for ACS patients.

Vanilloid-like agents inhibit aggregation of human platelets

INTRODUCTION

Plant-derived and endogenous vanilloid-like agents exert their effects on cells through transient receptor potential vanilloid-1 (TRPV1). Little is known about the effects of these agents on platelet aggregation. We investigated the effect of various vanilloid-like agents on in-vitro platelet aggregation and tested whether this action is mediated through TRPV1. Understanding the mechanism of action of these compounds in platelets is important in that these compounds may be developed as novel anti-platelet agents.

MATERIALS AND METHODS

The effects of plant-derived (capsaicin; dihydrocapsaicin, DHC) and endogenous vanilloid-like agents (N-oleoyldopamine, OLDA; N-arachidonoyl-dopamine, NADA) on platelet aggregation were investigated using ADP (5, 10μM), collagen (4, 8μg/mL) and arachidonic acid (AA, 300, 400μg/mL) as agonists. The direct effects of these agents on platelet viability were also determined using an LDH release assay.

RESULTS

Capsaicin, OLDA and NADA inhibited ADP-induced platelet aggregation in a concentration-dependent manner. OLDA and NADA, but not capsaicin and DHC, inhibited collagen-induced aggregation, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA, but not OLDA. Inhibition of aggregation was not due to direct toxicity of these agents towards platelets. The TRPV1 antagonist, SB-452533, did not affect inhibition of ADP-induced platelet aggregation by capsaicin and OLDA.

CONCLUSIONS

These results demonstrate that the endovanilloids, OLDA and NADA, and plant-derived vanilloid, capsaicin, inhibit ADP-induced platelet aggregation. Collagen-induced aggregation was inhibited only by endovanilloids, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA. This inhibition was not due to direct toxic effects of these agents, nor was inhibition of ADP-induced aggregation TRPV1 mediated.

NSAID-induced urticaria/angioedema does not evolve into chronic urticaria: a 12-year follow-up study

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequent medicaments involved in drug hypersensitivity reactions, with NSAID-induced urticaria/angioedema (NIUA) being the most frequent clinical entity. The natural evolution of NIUA has been suggested to lead to chronic urticaria (CU) in an important proportion of patients, such that NIUA may therefore precede CU. Our aim was to verify whether these entities are related by following up a large cohort of patients with NIUA as well as a control group over a long period of time.

METHODS

The study comprised three groups: (i) patients with a confirmed history of NIUA (more than two episodes with at least two different NSAIDs or positive drug provocation tests), (ii) patients with more than two episodes of urticaria/angioedema to a single NSAID with good tolerance to a strong COX-1 inhibitor and/or evidence by in vivo tests supporting specific IgE antibodies to the drug (single NSAID-induced urticaria/angioedema, SNIUA), and (iii) controls who tolerated NSAIDs. All cases in the three groups were followed up over a period of 12 years.

RESULTS

There were 190 patients with NIUA (64.6% female; mean age 43.71 ± 15.82 years, 110 with SNIUA, and 152 controls. At the 12-year evaluation, 12 patients with NIUA (6.15%) had developed CU over a 1- to 8-year period. Similar proportions were seen in SNIUA and controls.

CONCLUSIONS

Nonsteroidal anti-inflammatory drugs-induced urticaria/angioedema does not seem to precede the onset of CU over the medium term. Further research including a longer follow-up is necessary to verify this observation.

Variants of CEP68 gene are associated with acute urticaria/angioedema induced by multiple non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most consumed drugs worldwide because of their efficacy and utility in the treatment of pain and inflammatory diseases. However, they are also responsible for an important number of adverse effects including hypersensitivity reactions. The most important group of these reactions is triggered by non-immunological, pharmacological mechanisms catalogued under the denomination of cross-intolerance (CRI), with acute urticaria/angioedema induced by multiple NSAIDs (MNSAID-UA) the most frequently associated clinical entity. A recent genome-wide association study identified the gene encoding the centrosomal protein of 68 KDa (CEP68) as the major locus associated with aspirin intolerance susceptibility in asthmatics. In this study, we aimed to assess the role of this locus in susceptibility to CRI to NSAIDs by examining 53 common gene variants in a total of 635 patients that were classified as MNSAID-UA (n = 399), airway exacerbations (n = 110) or blended pattern (n = 126), and 425 controls. We found in the MNSAID-UA group a number of variants (17) associated (lowest p-value = 1.13×10⁻⁶), including the non-synonymous Gly74Ser variant (rs7572857) previously associated with aspirin intolerance susceptibility in asthmatics. Although not being significant in the context of multiple testing, eight of these variants were also associated with exacerbated respiratory disease or blended reactions. Our results suggest that CEP68 gene variants may play an important role in MNSAID-UA susceptibility and, despite the different regulatory mechanisms involved depending on the specific affected organ, in the development of hypersensitivity reactions to NSAIDs.

Multiple nonsteroidal anti-inflammatory drug-induced cutaneous disease: what differentiates patients with and without underlying chronic spontaneous urticaria?

BACKGROUND

Multiple nonsteroidal anti-inflammatory drug (NSAID) cutaneous reactors may be otherwise normal or have underlying chronic spontaneous urticaria (CSU). This study compared these two phenotypes of NSAID-hypersensitive subjects.

METHODS

A total of 97 multiple NSAID reactors underwent oral challenges with paracetamol, etoricoxib and tramadol. Atopic status was investigated in all patients, and autoreactivity was ascertained in some cases as well. Otherwise normal multiple NSAID reactors were reevaluated after 1-5 years in order to detect their proneness to CSU.

RESULTS

At the first visit, 41 patients had CSU and 56 had multiple NSAID intolerance without any underlying cutaneous disease. Altogether, 22, 10 and 6% of patients did not tolerate paracetamol, etoricoxib and tramadol, respectively, on oral challenge. Intolerance to these alternative drugs showed a strong association (p < 0.01 with all combinations). The two subgroups of patients did not show any difference in terms of mean age, gender distribution, prevalence of atopic diseases, prevalence of single offending NSAIDs and prevalence of intolerance to paracetamol, etoricoxib or tramadol on oral challenge. In all, 20% of multiple NSAID reactors without CSU at presentation developed CSU between 6 months and 5 years after the initial clinical evaluation.

CONCLUSIONS

Multiple NSAID cutaneous reactors with or without CSU seem identical from a clinical point of view, and some of the latter group show a propensity to acquire the former phenotype over time. A subset of patients apparently identical to the general population of multiple NSAID reactors also react to drugs exerting little or no cyclooxygenase-1 enzyme inhibition and might represent a distinct phenotype of NSAID-hypersensitive patients possibly characterized by a different underlying pathogenesis.