Lack of effect of the 5-lipoxygenase inhibitor zileuton in blocking oral aspirin challenges in aspirin-sensitive asthmatics

Urinary Leukotriene E4 as a Biomarker in NSAID-Exacerbated Respiratory Disease (N-ERD): a Systematic Review and Meta-analysis

PURPOSE OF REVIEW

Non-steroidal exacerbated respiratory disease (N-ERD) currently requires aspirin challenge testing for diagnosis. Urinary leukotriene E4 (uLTE₄) has been extensively investigated as potential biomarker in N-ERD. We aimed to assess the usefulness of uLTE₄ as a biomarker in the diagnosis of N-ERD.

RECENT FINDINGS

N-ERD, formerly known as aspirin-intolerant asthma (AIA), is characterised by increased leukotriene production. uLTE₄ indicates cysteinyl leukotriene production, and a potential biomarker in N-ERD. Although several studies and have examined the relationship between uLTE₄ and N-ERD, the usefulness of uLTE₄ as a biomarker in a clinical setting remains unclear.

FINDINGS

Our literature search identified 38 unique eligible studies, 35 were included in the meta-analysis. Meta-analysis was performed (i.e. pooled standardised mean difference (SMD) with 95% confidence intervals (95% CI)) and risk of bias assessed (implementing Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy (Cochrane DTA)). Data from 3376 subjects was analysed (1354 N-ERD, 1420 ATA, and 602 HC). uLTE₄ was higher in N-ERD vs ATA (n = 35, SMD 0.80; 95% CI 0.72-0.89). uLTE4 increased following aspirin challenge in N-ERD (n = 12, SMD 0.56; 95% CI 0.26-0.85) but not ATA (n = 8, SMD 0.12; CI - 0.08-0.33). This systematic review and meta-analysis showed that uLTE₄ is higher in N-ERD than ATA or HC. Likewise, people with N-ERD have greater increases in uLTE₄ following aspirin challenge. However, due to the varied uLTE₄ measurement and result reporting practice, clinical utility of these findings is limited. Future studies should be standardised to increase clinical significance and interpretability of the results.

The role of aspirin desensitization followed by oral aspirin therapy in managing patients with aspirin-exacerbated respiratory disease: A Work Group Report from the Rhinitis, Rhinosinusitis and Ocular Allergy Committee of the American Academy of Allergy, Asthma & Immunology

Aspirin-exacerbated respiratory disease (AERD) is characterized by the clinical triad of chronic rhinosinusitis with nasal polyps, asthma, and an intolerance to medications that inhibit the cycloxgenase-1 enzyme. Patients with AERD on average have more severe respiratory disease compared with patients with chronic rhinosinusitis with nasal polyps and/or asthma alone. Although patients with AERD traditionally develop significant upper and lower respiratory tract symptoms on ingestion of cycloxgenase-1 inhibitors, most of these same patients report clinical benefit when desensitized to aspirin and maintained on daily aspirin therapy. This Work Group Report provides a comprehensive review of aspirin challenges, aspirin desensitizations, and maintenance aspirin therapy in patients with AERD. Identification of appropriate candidates, indications and contraindications, medical and surgical optimization strategies, protocols, medical management during the desensitization, and recommendations for maintenance aspirin therapy following desensitization are reviewed. Also included is a summary of studies evaluating the clinical efficacy of aspirin therapy after desensitization as well as a discussion on the possible cellular and molecular mechanisms explaining how this therapy provides unique benefit to patients with AERD.

Lipid Mediators in Aspirin-Exacerbated Respiratory Disease

Aspirin-exacerbated respiratory disease (AERD) is a syndrome of severe asthma and rhinosinusitis with nasal polyposis with exacerbations of baseline eosinophil-driven and mast cell-driven inflammation after nonsteroidal antiinflammatory drug ingestion. Although the underlying pathophysiology is poorly understood, dysregulation of the cyclooxygenase and 5-lipoxygenase pathways of arachidonic acid metabolism is thought to be key. Central features of AERD pathogenesis are overproduction of proinflammatory and bronchoconstrictor cysteinyl leukotrienes and prostaglandin (PG) D₂ and inhibition of bronchoprotective and antiinflammatory PGE₂. Imbalance in the ratio of these lipid mediators likely leads to the increased eosinophilic and mast cell inflammatory responses in the respiratory tract.

Aspirin-exacerbated respiratory disease: Prevalence, diagnosis, treatment, and considerations for the future

Aspirin-exacerbated respiratory disease (AERD) is a late onset condition characterized by the Samter triad (aspirin sensitivity [as well as sensitivity to any nonselective cyclooxygenase inhibitor], nasal polyps, asthma) and additional features, including eosinophilic chronic rhinosinusitis, hypereosinophilia, anosmia, frequent absence of atopy, and, intolerance to ingestion of red wine and other alcoholic beverages. The diagnosis is rare, and, because of this, it is also often missed by physicians. However, it is highly overexpressed in patients with severe asthma (and severe chronic rhinosinusitis with nasal polyps), which makes its recognition essential. For this review, we considered mechanisms involved in the pathogenesis of this disease and discussed the clinical symptoms of AERD. We also discussed the role of aspirin desensitization in the treatment of AERD. Also, we considered medications (e.g, leukotriene modifiers) and surgical interventions that have a role in the treatment of AERD.

Performing Aspirin Desensitization in Aspirin-Exacerbated Respiratory Disease

Aspirin-exacerbated respiratory disease (AERD) is characterized by chronic rhinosinusitis with nasal polyps, asthma, and reactions to cyclooxygenase-1-inhibiting drugs. This condition is often refractory to standard medical treatments and results in aggressive nasal polyposis that often requires multiple sinus surgeries. Aspirin desensitization followed by daily aspirin therapy is an important treatment option, and its efficacy has been validated in multiple research studies. Aspirin desensitization is not without risk, but specific protocols and recommendations exist to mitigate the risk. Most patients with AERD can undergo aspirin desensitization in an outpatient setting under the supervision of an allergist.

Clinically relevant subgroups in COPD and asthma

As knowledge of airways disease has grown, it has become apparent that neither chronic obstructive pulmonary disease (COPD) nor asthma is a simple, easily defined disease. In the past, treatment options for both diseases were limited; thus, there was less need to define subgroups. As treatment options have grown, so has our need to predict who will respond to new drugs. To date, identifying subgroups has been largely reported by detailed clinical characterisation or differences in pathobiology. These subgroups are commonly called "phenotypes"; however, the problem of defining what constitutes a phenotype, whether this should include comorbid diseases and how to handle changes over time has led to the term being used loosely. In this review, we describe subgroups of COPD and asthma patients whose clinical characteristics we believe have therapeutic or major prognostic implications specific to the lung, and whether these subgroups are constant over time. Finally, we will discuss whether the subgroups we describe are common to both asthma and COPD, and give some examples of how treatment might be tailored in patients where the subgroup is clear, but the label of asthma or COPD is not.

Aspirin induces IL-4 production: augmented IL-4 production in aspirin-exacerbated respiratory disease

Aspirin hypersensitivity is a hallmark of aspirin-exacerbated respiratory disease (AERD), a clinical syndrome characterized by the severe inflammation of the respiratory tract after ingestion of cyclooxygenase-1 inhibitors. We investigated the capacity of aspirin to induce interleukin-4 (IL-4) production in inflammatory cells relevant to AERD pathogenesis and examined the associated biochemical and molecular pathways. We also compared IL-4 production in peripheral blood mononuclear cells (PBMCs) from patients with AERD vs aspirin-tolerant asthma (ATA) upon exposure to aspirin. Aspirin induced IL-4 expression and activated the IL-4 promoter in a report assay. The capacity of aspirin to induce IL-4 expression correlated with its activity to activate mitogen-activated protein kinases, to form DNA-protein complexes on P elements in the IL-4 promoter and to synthesize nuclear factor of activated T cells, critical transcription factors for IL-4 transcription. Of clinical importance, aspirin upregulated IL-4 production twice as much in PBMCs from patients with AERD compared with PBMCs from patients with ATA. Our results suggest that IL-4 is an inflammatory component mediating intolerance reactions to aspirin, and thus is crucial for AERD pathogenesis.

Aspirin and nonsteroidal anti-inflammatory drug hypersensitivity

Acetylsalicylic acid (ASA) or aspirin and nonsteroidal anti-inflammatory drug (NSAID) sensitivities encompass a diverse group of both pharmacological and hypersensitivity reactions. Conventionally, hypersensitivities include aspirin-exacerbated respiratory disease (AERD), ASA-induced urticaria, and anaphylaxis. With an increasing prevalence of coronary artery disease in an aging population, aspirin continues to play a significant role in cardiac prophylaxis in a large patient population. Invariably, the clinician will encounter patients with clear indications for aspirin therapy but a history of aspirin sensitivity. Although protocols have been established for aspirin challenge and desensitization, it is not always an efficacious or safe procedure. This article reviews the different classifications of ASA/NSAIDs hypersensitivities to better guide the clinician in dealing with this patient population. History of crossrelativities between multiple NSAIDs implies a non-IgE-mediated process. Similarly, a history of monosensitivity to one NSAID implies an IgE-mediated process, although specific antibodies are often elusive. Despite the name, AERD can potentially be exacerbated by all cyclooxygenase (COX) inhibitors based on dose-dependent inhibition of COX-1. Aspirin desensitization can be achieved to improve both upper and lower respiratory symptoms for most patient with AERD. Aspirin desensitization can usually be achieved for those in need of the antiplatelet effects of aspirin, with the exception of those with aspirin-induced urticaria and baseline chronic urticaria. However, desensitization should only be attempted in those with stable coronary artery disease because the process of desensitization carries the inherent risk of anaphylaxis/anaphylactoid reaction, which may further increase cardiac demand and bring about ischemic injury. Therefore, desensitization is reserved until coronary artery disease is stabilized.

Zileuton: clinical implications of 5-Lipoxygenase inhibition in severe airway disease

The 5-Lipoxygenase pathway results in the formation of leukotrienes, including leukotriene B(4) (LTB(4)), 5-oxo-6E,8Z,11Z,14Z-eicosatetranoic acid and the cysteinyl leukotrienes (LTC(4), LTD(4) and LTE(4)) and activates all four leukotriene receptors, BLT1, BLT2, cysLT(1) and cysLT(2). Zileuton is the only commercially available inhibitor of the 5-Lipoxygenase pathway. In a number of clinical trials, zileuton has been shown to improve airway function and inflammation, asthma symptom control and quality of life in asthmatics. Given the important role that leukotrienes play in airway inflammation, zileuton provides an additional therapeutic option in the management of chronic, persistent asthma, particularly those asthmatics with more severe disease. In addition, zileuton has shown promise in a number of other conditions, including upper airway inflammatory conditions, dermatological disease and chronic obstructive pulmonary disease. The development of new formulations, including a controlled release tablet formulation for b.i.d. dosing and an intravenous preparation for acute asthma exacerbations may enhance clinical utility and expand therapeutic indications.

Safety of etoricoxib, a specific cyclooxygenase-2 inhibitor, in asthmatic patients with aspirin-exacerbated respiratory disease

BACKGROUND

Treatment of rheumatic conditions is limited in patients with asthma owing to concerns of nonsteroidal anti-inflammatory drugs potentially provoking asthma. Cross-sensitivity to all anti-inflammatory drugs that inhibit cyclooxygenase enzymes occurs in these individuals.

OBJECTIVES

To study the safety of etoricoxib, a specific cyclooxygenase-2 inhibitor, and to determine whether it cross-reacts with asthma in patients with aspirin-exacerbated respiratory disease (AERD).

METHODS

This study included 77 patients who had experienced asthma induced by aspirin and at least 1 other nonsteroidal anti-inflammatory drug. Baseline evaluation included blood pressure measurement, nasal examination, spirometry, and peak expiratory flow rate measurement. Patients were given placebo the first day and then were challenged with once-daily etoricoxib in 3 different doses: 60 mg on day 2, 90 mg on day 3, and 120 mg on day 4. If no evidence of intolerance was seen, each patient was rechallenged with 60 or 90 mg of etoricoxib once daily (according to the rheumatic condition) 7 days later. Reassessment of the baseline measurements was performed daily from day 1 to day 4 after the initial challenge, on day 7 after rechallenge, and after 1 month of drug intake. If the patient developed any mucosal or skin reaction, hypotension, upper or lower airway obstruction, conjunctival reaction, or laryngeal edema during the challenge test, it was considered a positive response.

RESULTS

Etoricoxib was well tolerated, without any signs of immediate or delayed hypersensitivity in aspirin- and nonsteroidal anti-inflammatory drug-induced asthmatic patients. None of 77 study patients experienced any symptoms or developed dyspnea, change in nasal examination, significant variation in peak expiratory flow rate greater than 20%, or decline in forced expiratory volume in 1 second greater than 15% during etoricoxib challenge. The exact 1-sided confidence interval for the probability of etoricoxib inducing cross-reactions in patients with AERD was 0% to 2%.

CONCLUSIONS

These results confirm the lack of cross-reactivity between specific cyclooxygenase-2 inhibitors and aspirin in AERD. Etoricoxib was safe for treating inflammation in patients with AERD.

Failure of tacrolimus to prevent aspirin-induced respiratory reactions in patients with aspirin-exacerbated respiratory disease

BACKGROUND

In patients with aspirin-exacerbated respiratory disease (AERD), pretreatment with asthma controller medications (leukotriene modifiers, inhaled or systemic corticosteroids, and salmeterol) partially modifies the severity of aspirin-induced asthmatic reactions.

OBJECTIVE

A recent study showed that pretreatment with tacrolimus completely prevented aspirin-induced respiratory reactions and might allow silent aspirin desensitization.

METHODS

Ten patients with rhinosinusitis, nasal polyps, and asthma had a history of asthma attacks after ingesting aspirin and nonsteroidal anti-inflammatory drugs. All underwent baseline oral aspirin challenges and had typical respiratory reactions. They were then randomized to receive tacrolimus (0.1 mg/kg weight; 8 patients) or placebo (2 patients) in a double-blind protocol before rechallenge with aspirin using the previous provoking dose of aspirin. In addition, respiratory reactions sustained by 50 consecutive patients with AERD during 2004 were recorded, analyzed, and compared with the tacrolimus/placebo-treated patients to determine whether there were any differences.

RESULTS

Tacrolimus pretreatment failed to block respiratory reactions to provoking doses of aspirin in 5 of 8 patients with AERD, and in the other 3 patients did not block higher doses of aspirin. The results of oral aspirin challenges in the control population of 50 patients were compared with either the baseline or postchallenge data from the tacrolimus-pretreated or placebo-pretreated patients with AERD, and there were no significant differences.

CONCLUSIONS

Use of tacrolimus as add-on pretreatment to prevent reactions to aspirin in patients with AERD or to achieve the goal of silent aspirin desensitization could not be accomplished.

Aspirin-induced asthma: clinical aspects, pathogenesis and management

Aspirin (acetylsalicylic acid)-induced asthma (AIA) consists of the clinical triad of asthma, chronic rhinosinusitis with nasal polyps, and precipitation of asthma and rhinitis attacks in response to aspirin and other NSAIDs. The prevalence of the syndrome in the adult asthmatic populations is approximately 4-10%. Respiratory disease in these patients may be aggressive and refractory to treatment. The aetiology of AIA is complex and not fully understood, but most evidence points towards an abnormality of arachidonic acid (AA) metabolism. Cyclo-oxygenase (COX), the rate-limiting enzyme in AA metabolism, exists as two main isoforms. COX-1 is the constitutive enzyme responsible for synthesis of protective prostanoids, whereas COX-2 is induced under inflammatory conditions. A number of theories regarding its pathogenesis have been proposed. The shunting hypothesis proposes that inhibition of COX-1 shunts AA metabolism away from production of protective prostanoids and towards cysteinyl leukotriene (cys-LT) biosynthesis, resulting in bronchoconstriction and increased mucus production. The COX-2 hypothesis proposes that aspirin causes a structural change in COX-2 that results in the generation of products of the lipoxygenase pathway. It is speculated that this may result in the formation of mediators that cause respiratory reactions in AIA. Related studies provide evidence for abnormal regulation of the lipoxygenase pathway, demonstrating elevated levels of cys-LTs in urine, sputum and peripheral blood, before and following aspirin challenge in AIA patients. These studies suggest that cys-LTs are continually and aggressively synthesised before exposure to aspirin and, during aspirin-induced reactions, acceleration of synthesis occurs. A genetic polymorphism of the LTC4S gene has been identified consisting of an A to C transversion 444 nucleotides upstream of the first codon, conferring a relative risk of AIA of 3.89. Furthermore, carriers of the C444 allele demonstrate a dramatic rise in urinary LTE(4) following aspirin provocation, and respond better to the cys-LT antagonist pranlukast than A444 homozygotes.AIA patients have an aggressive form of disease, and treatment should include combination therapy with inhaled corticosteroids, beta(2)-adrenoceptor agonists and LT modifiers. Furthermore, recently developed inhibitors of COX-2 may be safer in patients with AIA.

Rhinosinusitis: establishing definitions for clinical research and patient care

Background

There is a need for more research on all forms of rhinosinusitis. Progress in this area has been hampered by a lack of consensus definitions and the limited number of published clinical trials.

Objectives

To develop consensus definitions for rhinosinusitis and outline strategies useful in clinical trials.

Methods

Five national societies, The American Academy of Allergy, Asthma and Immunology; The American Academy of Otolaryngic Allergy; The American Academy of Otolaryngology Head and Neck Surgery; The American College of Allergy, Asthma and Immunology; and the American Rhinologic Society formed an expert panel from multiple disciplines. Over two days, the panel developed definitions for rhinosinusitis and outlined strategies for design of clinical trials.

Results

Committee members agreed to adopt the term “rhinosinusitis” and reached consensus on definitions and strategies for clinical research on acute presumed bacterial rhinosinusitis, chronic rhinosinusitis without polyposis, chronic rhinosinusitis with polyposis, and classic allergic fungal rhinosinusitis. Symptom and objective criteria, measures for monitoring research progress, and use of symptom scoring tools, quality-of-life instruments, radiologic studies, and rhinoscopic assessment were outlined for each condition.

Conclusion

The recommendations from this conference should improve accuracy of clinical diagnosis and serve as a starting point for design of rhinosinusitis clinical trials.

Rhinosinusitis: Establishing definitions for clinical research and patient care

Background

There is a need for more research on all forms of rhinosinusitis. Progress in this area has been hampered by a lack of consensus definitions and the limited number of published clinical trials.

Objectives

To develop consensus definitions for rhinosinusitis and outline strategies useful in clinical trials.

Study design

Five national societies, The American Academy of Allergy, Asthma and Immunology; The American Academy of Otolaryngic Allergy; The American Academy of Otolaryngology Head and Neck Surgery; The American College of Allergy, Asthma and Immunology; and the American Rhinologic Society formed an expert panel from multiple disciplines. Over two days, the panel developed definitions for rhinosinusitis and outlined strategies for design of clinical trials.

Results

Committee members agreed to adopt the term “rhinosinusitis” and reached consensus on definitions and strategies for clinical research on acute presumed bacterial rhinosinusitis, chronic rhinosinusitis without polyposis, chronic rhinosinusitis with polyposis, and classic allergic fungal rhinosinusitis. Symptom and objective criteria, measures for monitoring research progress, and use of symptom scoring tools, quality-of-life instruments, radiologic studies, and rhinoscopic assessment were outlined for each condition.

Conclusions

The recommendations from this conference should improve accuracy of clinical diagnosis and serve as a starting point for design of rhinosinusitis clinical trials.

Safety of high-dose rofecoxib in patients with aspirin-exacerbated respiratory disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is characterized by progressive sinusitis, nasal polyposis, and asthma that begins and continues in the absence of exposure to aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). Cross-sensitivity to all NSAIDs that inhibit cyclooxygenase-1 (COX-1) occurs in these individuals. Reactions to aspirin and NSAIDs in patients with AERD are largely due to inhibition of COX-1. Despite accumulating data on the safety of COX-2 selective inhibitors in AERD, concern still remains that high doses of a COX-2 inhibitor may be sufficient to induce a cross-reaction.

OBJECTIVE

To determine whether high-dose rofecoxib cross-reacts in patients with AERD and asthma.

METHODS

Sixty asthmatic patients underwent blinded placebo-controlled oral challenges with 50 mg of rofecoxib. Aspirin sensitivity was subsequently confirmed in all patients with the use of single-blinded aspirin challenges.

RESULTS

None of the 60 patients experienced any symptoms, changes in nasal examination results, or declines in lung function during rofecoxib challenge. All 60 patients experienced respiratory reactions to aspirin challenge, with a mean provoking dose of 57 mg. The exact 1-sided 95% confidence interval for the underlying probability of 50 mg of rofecoxib inducing respiratory cross-reactions in patients with AERD is 0 to 0.05, or 0% to 5%.

CONCLUSIONS

These results confirm the lack of cross-reactivity of aspirin and the highly selective COX-2 inhibitors in AERD. We suggest that it is time for the labeling of highly selective COX-2 inhibitors to reflect these data and for the warning that patients with AERD in particular and asthmatic patients in general avoid selective COX-2 inhibitors to be removed.

Adverse respiratory reactions to aspirin and nonsteroidal anti-inflammatory drugs

Aspirin-exacerbated respiratory disease (AERD) is an adult-onset condition that manifests as asthma, rhinosinusitis/nasal polyps, and sensitivity to aspirin and other cyclooxygenase-1 (COX-1)-inhibitor nonsteroidal anti-inflammatory drugs (NSAIDs). There is no cross-sensitivity to highly selective COX-2 inhibitors. AERD is chronic and does not improve with avoidance of COX-1 inhibitors. The diagnosis of AERD is made through provocative challenge testing. Following a positive aspirin challenge, patients can be desensitized to aspirin and NSAIDs. The desensitized state can be maintained indefinitely with continued daily administration. After desensitization, there is an approximately 48-hour refractory period to adverse effects from aspirin. The pathogenesis of AERD remains unknown, but these patients have been shown to have multiple abnormalities in arachidonic acid metabolism and in cysteinyl leukotriene 1 receptors. AERD patients can take up to 650 mg of acetaminophen for analgesic or antipyretic relief. Patients can also use weak COX-1 inhibitors, such as sodium salicylate or choline magnesium trisalicylate. Treatment of AERD patients with antileukotriene medications has been helpful but not preferential when compared with non-AERD patients. An alternative treatment for many AERD patients is aspirin desensitization. This is particularly effective in reducing upper-airway mucosal congestion, nasal polyp formation, and systemic steroids.

The office management of recalcitrant rhinosinusitis

The patient referred to the otolaryngologist for the treatment of CRS has received many therapies for the condition. Newer therapies available focus on the anti-inflammatory therapies and local application of antimicrobial and antifungal agents to the sinus cavities. Much clinical work remains to be done to prove the efficacy of currently available treatments. The recent advances in the understanding of allergic and immune mechanisms may allow eventual intervention at the level of cytokines and other immunomodulators of inflammation. The complex cascade of interleukins and proinflammatory agents in CRS patients may some day allow "silver bullet" therapies in the properly selected patient. Until then, a systematic approach to the evaluation of these patients and management with the currently available treatment modalities may help relieve the symptoms in patients with CRS.

Safety of COX-2 inhibitors in asthma patients with aspirin hypersensitivity

OBJECTIVE

To review the safety of cyclooxygenase-2 (COX-2) inhibitors in asthma patients with aspirin hypersensitivity.

DATA SOURCES

Clinical studies were identified using MEDLINE (1966-September 2002). Key search terms included cyclooxygenase inhibitors, aspirin, asthma, and hypersensitivity. English-language articles were identified and included. References from the identified articles were also reviewed.

DATA SYNTHESIS

The literature provides information regarding the safety of COX-2 inhibitors in asthma patients with aspirin-exacerbated respiratory disease (AERD). The mechanism of AERD involves inhibition of cyclooxygenase, particularly COX-1. Inhibition of COX-1 causes an increased production of certain inflammatory mediators, which results in the reactions seen with AERD. Considering this mechanism, COX-2 inhibitors may be an alternative to aspirin or nonsteroidal antiinflammatory drugs (NSAIDs) in a patient with AERD. This article analyzes 4 studies to evaluate the safety of COX-2 inhibitors in this population.

RESULTS

The 4 studies evaluated included a total of 172 patients with AERD. All patients included demonstrated intolerance to aspirin or NSAIDs and tolerated the selective COX-2 inhibitor administered.

CONCLUSIONS

COX-2 inhibitors provide a potentially safe alternative for treatment of inflammatory conditions in patients with AERD.

Adverse reactions to aspirin and nonsteroidal antiinflammatory drugs (NSAIDs)

BACKGROUND

Aspirin can provoke reactions ranging from respiratory to cutaneous in those susceptible individuals. There has been particular attention looking at the role of cyclooxygenase enzymes and 2 and their role in aspirin exacerbated respiratory disease.

OBJECTIVE

Patients who present with a spectrum of allergic and pseudoallergic reactions to aspirin pose a special challenge for the physician. This article discusses proposed classification system, clinical manifestations, pathogenesis of disease, and current treatment options of aspirin related disease.

METHODS

Relevant articles in the medical literature were. derived from searching the MEDLINE database. Sources also include review articles, randomized control trials, and standard textbooks of allergy and immunology.

RESULTS

Aspirin-exacerbated respiratory disease remains a complex, heterogeneous disease with manvaried clinical presentations. There have been many advances in trying to elucidate the pathogenesis of this disease. The classification system presented will provide greater ease when reading the literature and communicating with one another. Oral aspirin challenge remains the diagnostic test of choice for both respiratory and cutaneous reactions. Aspirin desensitization is an option for those with refractory respiratory disease or who require aspirin for other medical conditions.

CONCLUSIONS

This review discusses the challenges in classification, diagnosis and treatment of those patients with a sensitivity to aspirin. Special attention is made to the possible mechanisms mediating disease progression and how specific. Therapies, such as the leukotriene modifiers may be helpful.

Natural history and clinical features of aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is a clinical syndrome characterized by chronic rhinosinusitis, nasal polyposis, asthma and precipitation of asthma, and rhinitis attacks after ingestion of aspirin (ASA) and most other nonsteroidal antiinflammatory drugs (NSAIDs). Although precipitation of asthma attacks by ingestion of ASA and other NSAIDs is considered a hallmark of the syndrome, the respiratory mucosal inflammatory disease process begins and continues in the absence of ongoing or even intermittent exposure to ASA or NSAIDs. The typical patient with AERD is an adult who develops refractory chronic rhinitis in the third or fourth decade of life. The chronic rhinitis evolves into chronic eosinophilic rhinosinusitis with associated nasal polyposis. Anosmia appears in most patients. CT of the sinuses most often demonstrates pansinusitis and patients often undergo multiple sinus operations resulting in only limited temporary benefit. During the evolution of the sinus disease persistent asthma develops. Finally, if patients are exposed to ASA or NSAIDs acute respiratory reactions begin to occur. Despite subsequent avoidance of ASA and other NSAIDs, the respiratory mucosal inflammatory disease persists, often requiring systemic corticosteroids for control of both upper- and lower-respiratory tract symptoms. Adequate control of asthma can often only be accomplished with the simultaneous control of the associated rhinosinusitis. With few exceptions, once AERD develops it remains for the remainder of the patient s life.

Sensitivity to nonsteroidal anti-inflammatory drugs

BACKGROUND

Aspirin can provoke reactions ranging from respiratory to cutaneous in susceptible individuals. There has been particular attention looking at the role of cyclo-oxygenase enzymes 1 and 2 and their role in aspirin-exacerbated respiratory disease.

OBJECTIVE

Patients who present with a spectrum of allergic and pseudoallergic reactions to aspirin pose a special challenge for the physician. This article discusses proposed classification system, clinical manifestations, pathogenesis of disease, and current treatment options of aspirin-related disease.

DATA SOURCES

Relevant articles in the medical literature were derived from searching the MEDLINE database with key terms aspirin-sensitive asthma, cyclo-oxygenase enzymes 1 and 2. Sources also include review articles, randomized control trials, and standard textbooks of allergy and immunology.

RESULTS

Aspirin-exacerbated respiratory disease remains a complex, heterogenous disease with varied clinical presentations. There have been many advances in trying to elucidate the pathogenesis of this disease. The classification system presented will provide greater ease when reading the literature and communicating with one another. Oral aspirin challenge remains the diagnostic test of choice for both respiratory and cutaneous reactions. Aspirin desensitization is an option for those with refractory respiratory disease or who require aspirin for other medical conditions.

CONCLUSIONS

This review discusses the challenges in classification, diagnosis, and treatment of those patients with a sensitivity to aspirin. Special attention is made to the possible mechanisms mediating disease progression and how specific therapies, such as leukotriene modifiers, may be helpful.

The effect of leukotriene-modifier drugs on aspirin-induced asthma and rhinitis reactions

BACKGROUND

Leukotrienes (LTs) appear to be crucial mediators of aspirin (ASA)-induced lower respiratory tract reactions. Therefore, it is logical to assume that leukotriene-modifier drugs (LTMDs) might block these reactions.

OBJECTIVE

The aim of this study was to determine whether concomitant treatment with LTMDs was associated with a reduction of ASA-provoked lower respiratory tract reactions in patients with aspirin-exacerbated respiratory disease (AERD), when compared to AERD patients who were not treated with LTMDs. Secondly, if ASA-induced lower respiratory tract reactions were prevented in LTMD-treated patients, was there then a higher prevalence of upper respiratory reactors or, alternatively, a higher prevalence of blocked reactions ('non-reactors') in this group.

METHODS

Of 271 patients suspected by history of having AERD, 96 were taking cys-LT receptor antagonists (cys-LTRAs) and 12 were taking zileuton at the time of oral ASA challenges. A matched control group of 163 patients was not receiving LTMDs. All subjects underwent standard oral ASA challenges. Reactions were classified as follows: classic [naso-ocular combined with a 20% or > decline in forced expiratory volume of 1 s (FEV1)]; pure lower (20% or > decline in FEV1 without naso-ocular); partial asthma (naso-ocular + 15-20% decline in FEV1); upper only (naso-ocular with < 15% decline in FEV1); negative (no reactions).

RESULTS

In patients treated with cys-LTRAs, there were significant reductions in numbers of patients with ASA-induced bronchospastic reactions and a concomitant increase in upper respiratory reactors. There were no significant differences in mean provoking doses of ASA or the percent changes in FEV1 values in both groups. In the 12 patients receiving zileuton, no reactions to ASA (16%) were similar to the cys-LTRA-treated group (11%) and the control group (15%).

CONCLUSION

During oral ASA challenges, LTMD treatment appeared to shift target organ responses from both upper and lower respiratory tracts to upper tract alone. LTMD blocking of the entire respiratory tract did not appear to occur.

Leukotriene modifiers to prevent aspirin-provoked respiratory reactions in asthmatics

OBJECTIVE

To evaluate the use of leukotriene modifiers in preventing aspirin-provoked respiratory reactions in asthmatics.

DATA SOURCES

Clinical literature accessed through MEDLINE (1965-February 2001). Key search terms included aspirin, asthma, leukotriene, and treatment.

DATA SYNTHESIS

Aspirin-sensitive asthmatics experience a wide variety of symptoms, ranging from rhinitis to life-threatening bronchospasms, after the ingestion of aspirin or nonsteroidal antiinflammatory drugs (NSAIDs). The relationship between aspirin sensitivity, asthma, and nasal polyps was first reported in 1922. The exact mechanism of these reactions is not clearly understood. Four studies investigated the use of leukotriene modifiers to prevent aspirin-provoked respiratory reactions. The efficacy of these agents ranged from complete inhibition to no blockade.

CONCLUSIONS

Patients who experience aspirin-sensitive asthma should be cautious when taking aspirin and NSAIDs, despite treatment with leukotriene inhibitors.

The safety of celecoxib in patients with aspirin-sensitive asthma

OBJECTIVE

To determine whether celecoxib, a selective cyclooxygenase 2 (COX-2) inhibitor, cross-reacts in patients with aspirin-exacerbated respiratory disease (AERD) with asthma.

METHODS

Sixty patients with asthma underwent double-blinded, placebo-controlled oral challenges with celecoxib (100 mg, 200 mg, and 2 placebos) over 48 hours in our General Clinical Research Center. The next day, sensitivity to acetylsalicylic acid (ASA) was proven in all patients with the use of single-blinded ASA challenges.

RESULTS

None of the 60 patients experienced any symptoms, changes in nasal examinations, or declines in forced expiratory volume in 1 second during the celecoxib challenges. All 60 patients experienced oculonasal and/or asthmatic reactions to ASA, with a mean provoking dose of 69 mg. The exact 1-sided confidence interval for the probability of celecoxib inducing cross-reactions in AERD patients was calculated to be between 0% and 5%.

CONCLUSION

Cross-reactivity between ASA and celecoxib does not occur in patients with AERD. These results do not preclude the possibility of other types of immune reactions occurring with celecoxib after prior exposure. Our results add to the growing body of evidence that inhibition of COX-1 is a critical initiating event in the precipitation of respiratory reactions in AERD patients following ingestion of nonsteroidal antiinflammatory drugs.

Treatment of disseminated granuloma annulare with a 5-lipoxygenase inhibitor and vitamin E

Histologically, granuloma annulare (GA) is a common non-infectious necrobiotic granulomatous reaction pattern that correlates with a number of different, but relatively specific clinical presentations. The cause or causes of GA are unknown: when localized, it is usually self-limiting, but it may be persistent when disseminated. We present three women who had had disseminated GA for more than 1 year. One patient had previously been treated with isotretinoin with no response. All three patients were treated with vitamin E 400 IU daily and zileuton 2400 mg daily. All responded within 3 months with complete clinical clearing. The anti-inflammatory and immune regulatory effects of vitamin E and zileuton may be an effective treatment in some patients with prolonged disseminated/generalized GA.

Leukotriene inhibitors and non-steroidal therapies in the treatment of asthma

Asthma is the most common chronic disease of childhood whose morbidity and mortality continues to rise [1]. Drugs used in the treatment of asthma must be targeted at reversing three principle pathophysiologic features: bronchoconstriction, mucus plugging/hypersecretion and inflammation. In the past two decades, the contribution of airway inflammation to the development and progression of asthma symptoms and airway pathology has become a critical focus. Chronic airway inflammation can lead to the progressive decline and irreversible loss of lung function and airway remodelling [2]. In recent years, therapies aimed at diminishing airway inflammation have been at the forefront of asthma management. Steroids have been extensively studied and used as primary anti-inflammatory agents in the management of the asthmatic patient with persistent symptoms of varying severity. Within the last decade, however, several additional non-steroidal classes of drugs have begun to emerge as anti-inflammatory agents for the treatment of asthma. This article will focus on these non-steroidal drugs which have been developed and investigated within the last 5 years. Particular emphasis will be placed on leukotriene receptor antagonists, but anti-IgE and anti-IL-4 therapies, as well as phosphodiesterase inhibitors will also be discussed. Of these new therapies, only two leukotriene receptor antagonists, montelukast (Singulairtrade mark, Merck) and zafirlukast (Accolatetrade mark, AstraZeneca) and the 5-lipoxygenase inhibitor, zileuton (Zyflotrade mark, Abbott Laboratories), have been recommended, approved and are currently available for use in the treatment of paediatric patients with asthma in the United States.

Montelukast is only partially effective in inhibiting aspirin responses in aspirin-sensitive asthmatics

BACKGROUND

Leukotrienes have been implicated as major mediators of ASA-induced respiratory reactions. In several prior studies, pretreatment of ASA-sensitive respiratory disease (ASRD) patients with leukotriene modifiers have sometimes allowed subjects to tolerate previously established provoking doses of oral ASA or inhalation ASA-lysine, without respiratory reactions.

OBJECTIVE

The purpose of this study was to examine whether ASA-provoked respiratory reactions would be blocked or attenuated by pretreatment with a cystLT1 receptor antagonist, montelukast, particularly if ASA doses were increased above their threshold doses.

METHODS

Baseline ASA oral challenges were performed. Eight to 12 days later, following pretreatment with montelukast 10 mg daily, threshold and then escalating doses of ASA were used during repeat oral ASA challenges. The differences in responses between baseline and montelukast protected ASA oral challenges were then compared.

RESULTS

Nine of 10 patients, despite pretreatment with montelukast, experienced at least naso-ocular reactions during their second oral ASA challenges. In four of nine patients, asthmatic reactions also occurred. In comparing baseline and montelukast protected ASA challenges, there were no statistically significant differences in their responses.

CONCLUSIONS

Pretreatment with montelukast allowed only one patient to proceed through all challenge doses of ASA without any reactions. The remaining nine patients enjoyed only partial protection from respiratory reactions. Montelukast pretreatment was generally not effective in altering upper airway reactions and only partly effective in altering lower airway reactions.