Leukotriene receptor antagonists may prevent NSAID-induced exacerbations in patients with chronic urticaria

Dietary strategies for chronic spontaneous urticaria: an evidence-based review

Although the relationship between diet and chronic spontaneous urticaria (CSU) remains elusive, several patients seek dietary modifications as they are easy and cost-effective. Adequate patient education and counseling are crucial as modified diets may be beneficial for a subset of antihistamine refractory CSU patients, and no modality currently exists to identify these patients. Elimination of food items based exclusively on patient history may lead to unnecessary restrictions in most cases resulting in nutritional deficiencies and impaired quality of life. Several dietary strategies have been tried till date with varying rates of success and evidence. This review highlights the various dietary strategies along with their levels of evidence, which may help the treating dermatologists and physicians to counsel CSU patients and make evidence-based treatment decisions. There is grade A recommendation for the elimination of food additives (artificial pseudoallergens), personalized diets, vitamin D supplementation, Diamine oxidase supplementation and probiotics (in children), grade B recommendation for dietary elimination of red meat, fish and their products, natural pseudoallergens (fruits, vegetables, and spices), and low-histamine diet, while dietary elimination of gluten (with concomitant celiac disease) has grade C recommendation. Notably, elimination diets should be continued for at least 3 consecutive weeks to assess their effectiveness.

Current and emerging pharmacotherapy for chronic spontaneous Urticaria: a focus on non-biological therapeutics

INTRODUCTION

Chronic spontaneous urticaria (CSU) refers to urticaria (wheals) or angioedema, which occur for a period of six weeks or longer without an apparent cause. The condition may impair the patient's quality of life.

AREAS COVERED

Treatment for CSU is mainly symptomatic. Both AAAAI/ACAAI practice parameters and EAACI/GA2LEN/EDF/WAO guidelines suggest CSU management in a stepwise manner. First-line therapy is with second-generation H₁-antihistamines. Treatment should be stepped up along the algorithm if symptoms are not adequately controlled. Increasing the dosage of second-generation H₁-antihistamines, with the addition of first-generation H₁-antihistamines, H₂ antagonist, omalizumab, ciclosporin A, or short-term corticosteroid may be necessary. New medications are being developed to treat refractory CSU. They include spleen tyrosine kinase inhibitor, Bruton tyrosine kinase inhibitor, prostaglandin D₂ receptor inhibitor, H₄-antihistamine, and other agents. The authors discuss these treatments and provide expert perspectives on the management of CSU.

EXPERT OPINION

Second-generation H₁-antihistamines remain the first-line therapeutic options for the management of CSU. For patients not responding to higher-dose H₁-antihistamines, international guidelines recommend the addition of omalizumab. Efficacy and safety data for newer agents are still pending. Large-scale, well-designed, randomized, double-blind, placebo-controlled trials will further provide evidence on the safety profile and efficacy of these agents in patients with CSU.

Chronic urticaria and drug hypersensitivity in children

The cause of chronic urticaria remains often elusive. The association between chronic urticaria and intake of medications have been reported in children. However, the causative role of drugs has been rarely ascertained by onset of symptoms on drug provocation test. Chronic urticaria can be mediated by immunologic and nonimmunologic mechanisms. The diagnostic work-up of chronic urticaria includes a comprehensive evaluation of triggering factors such as drugs. A diagnosis is necessary in order to permit a safely administration of drugs in children with chronic urticaria.

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.

Clinical management of patients with a history of urticaria/angioedema induced by multiple NSAIDs: an expert panel review

Nonsteroidal anti-inflammatory drugs (NSAIDs) represent one of the most frequent causes of drug-induced urticaria/angioedema worldwide. Recent review articles have classified patients experiencing NSAID-induced urticaria/angioedema into different categories, including single reactors, multiple reactors, and multiple reactors with underlying chronic urticaria. Each of these categories requires a different clinical approach. The present article, written by a panel of experts, reports the main recommendations for the practical clinical management of patients with a history of urticaria/angioedema induced by multiple NSAID based on current knowledge.

5-Lipoxygenase metabolic contributions to NSAID-induced organ toxicity

Cyclooxygenase (COX)-1, COX-2, and 5-lipoxygenase (5-LOX) enzymes produce effectors of pain and inflammation in osteoarthritis (OA) and many other diseases. All three enzymes play a key role in the metabolism of arachidonic acid (AA) to inflammatory fatty acids, which contribute to the deterioration of cartilage. AA is derived from both phospholipase A(2) (PLA(2)) conversion of cell membrane phospholipids and dietary consumption of omega-6 fatty acids. Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit the COX enzymes, but show no anti-5-LOX activity to prevent the formation of leukotrienes (LTs). Cysteinyl LTs, such as LTC(4), LTD(4), LTE(4), and leukoattractive LTB(4) accumulate in several organs of mammals in response to NSAID consumption. Elevated 5-LOX-mediated AA metabolism may contribute to the side-effect profile observed for NSAIDs in OA. Current therapeutics under development, so-called "dual inhibitors" of COX and 5-LOX, show improved side-effect profiles and may represent a new option in the management of OA.

Hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs) - classification, diagnosis and management: review of the EAACI/ENDA(#) and GA2LEN/HANNA*

Nonsteroidal anti-inflammatory drugs (NSAIDs) are responsible for 21-25% of reported adverse drug events which include immunological and nonimmunological hypersensitivity reactions. This study presents up-to-date information on pathomechanisms, clinical spectrum, diagnostic tools and management of hypersensitivity reactions to NSAIDs. Clinically, NSAID hypersensitivity is particularly manifested by bronchial asthma, rhinosinusitis, anaphylaxis or urticaria and variety of late cutaneous and organ-specific reactions. Diagnosis of hypersensitivity to a NSAID includes understanding of the underlying mechanism and is necessary for prevention and management. A stepwise approach to the diagnosis of hypersensitivity to NSAIDs is proposed, including clinical history, in vitro testing and/or provocation test with a culprit or alternative drug depending on the type of the reaction. The diagnostic process should result in providing the patient with written information both on forbidden and on alternative drugs.

Association of thromboxane A2 receptor (TBXA2R) gene polymorphism in patients with aspirin-intolerant acute urticaria

BACKGROUND

The thromboxane A2 receptor (TBXA2R) is a potent broncho- and vaso-constrictor and is associated with leukotriene synthesis. Polymorphisms in the TBXA2R gene have been linked to atopy, asthma, and atopic dermatitis. This study evaluated the association between genetic TBXA2R variants and the development of acetyl salicylic acid (ASA)-intolerant acute urticaria (AIAU).

METHODS

AIAU patients (n=167), ASA-intolerant chronic urticaria (AICU) patients (n=149), and healthy controls (NC) (n=265) were included. All patients were enrolled at Ajou University Hospital in Suwon, Korea. Two TBXA2R polymorphisms (-4684T>C and 795T>C) were genotyped by primer extension using a SNAPshot ddNTP primer extension kit. Luciferase activity was measured using a dual-luciferase reporter assay kit. An electrophoretic mobility shift assay (EMSA) was performed using a nuclear extract from a human mast cell line (HMC-1).

RESULTS

Genetic association data demonstrated that compared with NC subjects, AIAU patients had a significantly higher frequency of the homozygous TT genotype of TBXA2R-4684T>C (P=0.005, P(corr) =0.03). No differences were identified between the AICU and the NC groups. Luciferase activity, reflecting promoter activity, was significantly lower with the TBXA2R-4684T-containing construct than with the -4684C-containing construct (P<0.001); the activity decreased further upon co-transfection with ETS-like gene transcription factor-1 (ELK-1) (P=0.012). EMSA revealed that the -4684T allele produced a specific shifted band, with a greater affinity than that produced by the -4684C allele.

CONCLUSION AND CLINICAL RELEVANCE

These results suggest that the TBXA2R-4684T allele may be associated with lower TBXA2R expression, which may contribute to the development of the AIAU phenotype.

The employment of leukotriene antagonists in cutaneous diseases belonging to allergological field

Leukotrienes (LTs) are potent biological proinflammatory mediators. LTC4, LTD4, and LTE4 are more frequently involved in chronic inflammatory responses and exert their actions binding to a cysteinyl-LT 1 (CysLT1) receptor and a cysteinyl-LT 2 (CysLT2) receptor. LTs receptor antagonists available for clinical use demonstrate high-affinity binding to the CysLT1 receptor. In this paper the employment of anti-LTs in allergic cutaneous diseases is analyzed showing that several studies have recently reported a beneficial effects of these agents (montelukast and zafirlukast as well as zileuton) for the treatment of some allergic cutaneous related diseases-like chronic urticaria and atopic eczema although their proper application remains to be established.

Association of TNF-alpha promoter polymorphisms with aspirin-induced urticaria

OBJECTIVE

Although the pathogenesis of aspirin-induced urticaria (AIU) is not fully understood, mast cell activation has been noted in patients with AIU. Tumour necrosis factor (TNF)-alpha, a potent pro-inflammatory cytokine, is released by human skin mast cells and other inflammatory cells in patients with urticaria. To investigate the role of TNF-alpha promoter polymorphisms in the development of AIU, we performed an association study of TNF-alpha promoter polymorphisms with AIU phenotype.

METHODS

Two hundred thirty-nine patients with AIU consisting of 120 patients with aspirin intolerant chronic urticaria (AICU) and 119 with aspirin-intolerant acute urticaria (AIAU), and 524 normal controls were enrolled. AIU was confirmed by oral aspirin challenge test. Five SNPs in the TNF-alpha gene (-1031T>C, -863C>A, -857C>T, -308G>A, -238G>A) were genotyped by a single-base extension method. Haplotype analyses were done.

RESULTS

The genotype frequencies of TNF-1031T>C and TNF-863C>A were significantly higher in the AIU patients than in the normal controls in both co-dominant (P = 0.014, P = 0.007) and dominant (P = 0.007, P = 0.004) models. The frequency of TNF-ht2[CACGG] containing a genotype in the AIU group was significantly higher in the normal controls with both co-dominant (P = 0.004, Pc = 0.02) and dominant models (P = 0.002, Pc = 0.01).

CONCLUSIONS

These findings suggest that the two promoter polymorphisms of TNF-alpha at -1031T>C and -863C>A may contribute to the development of AIU.

Urticaria : a review

Urticaria is often classified as acute, chronic, or physical based on duration of symptoms and the presence or absence of inducing stimuli. Urticarial vasculitis, contact urticaria, and special syndromes are also included under the broad heading of urticaria. Recent advances in our understanding of the pathogenesis of chronic urticaria include the finding of autoantibodies to mast cell receptors in nearly half of patients with chronic idiopathic urticaria. These patients may have more severe disease and require more aggressive therapies. Extensive laboratory evaluation for patients with chronic urticaria is typically unrevealing and there are no compelling data that associate urticaria with chronic infections or malignancy. Pharmacologic therapy consists primarily of the appropriate use of first- and second-generation histamine H(1) receptor antihistamines. Additional therapy may include leukotriene receptor antagonists, corticosteroids, and immunomodulatory agents for severe, unremitting disease. Despite our greater understanding of the pathogenesis of urticaria, the condition remains a frustrating entity for many patients, particularly those with chronic urticaria.

[Safety of reintroducing platelet-inhibitory doses of aspirin in patients with urticaria or angioedema induced by anti-inflammatory doses]

BACKGROUND

Aspirin is one of the most widely prescribed drugs in the world on account of its analgesic, antipyretic, and anti-inflammatory properties. Its effect on platelet aggregation makes it the first choice for prophylaxis in cardiovascular, neurological and obstetric diseases. However, a history of aspirin-induced urticaria and/or angioedema is usually a contraindication for further prescription of the drug. The aim of this article was to demonstrate that patients presenting aspirin-induced cutaneous reactions at anti-inflammatory doses can safely benefit from aspirin reintroduction at platelet-inhibitory doses.

PATIENTS AND METHODS

Patients with a history of aspirin-induced urticaria and/or angioedema referred to our department between January 2000 and June 2008 for double-blind placebo-controlled reintroduction at platelet-inhibitory doses for a medical indication were enrolled in this study.

RESULTS

Seventy patients with aspirin hypersensitivity as well as a medical indication for this therapy were referred to our department. Of these, 38 (54.3%) had a history of aspirin-induced urticaria and/or angioedema, including three laryngeal oedemas (7.9%). All subjects received platelet-inhibitory doses of aspirin (maximal total dose: 400mg/day) in double-blind placebo-controlled fashion during a one-day hospitalization period. None of the patients presented an immediate hypersensitivity reaction. Only one patient, who had received a cumulative dose of 200mg/day, reported diffuse urticaria and facial angioedema of no clinical significance the following day. He had a history of chronic urticaria.

CONCLUSION

This article demonstrates the safety of reintroducing platelet-inhibitory doses of aspirin in patients in whom it is indicated and reporting aspirin-induced urticaria and/or angioedema with anti-inflammatory doses. However, patients with a history of chronic urticaria should undergo a challenge with the lowest platelet-inhibitory dose (75mg/day) in order to minimize the risk of aggravating their condition.

Leukotriene receptor antagonists in monotherapy or in combination with antihistamines in the treatment of chronic urticaria: a systematic review

In vitro and in vivo clinical and experimental data have suggested that leukotrienes play a key role in inflammatory reactions of the skin. Antileukotriene drugs, ie, leukotriene receptor antagonists and synthesis inhibitors, are a class of anti-inflammatory drugs that have shown clinical efficacy in the management of asthma and in rhinitis with asthma. We searched MEDLINE database and carried out a manual search on journals specializing in allergy and dermatology for the use of antileukotriene drugs in urticaria. Montelukast might be effective in chronic urticaria associated with aspirin (ASA) or food additive hypersensitivity or with autoreactivity to intradermal serum injection (ASST) when taken with an antihistamine but not in mild or moderate chronic idiopathic urticaria [urticaria without any possible secondary causes (ie, food additive or ASA and other NSAID hypersensitivity, or ASST)]. Evidence for the effectiveness of zafirlukast and the 5-lipoxygenase inhibitor, zileuton, in chronic urticaria is mainly anecdotal. In addition, there is anecdotal evidence of effectiveness of antileukotrienes in primary cold urticaria, delayed pressure urticaria and dermographism. No evidence exists for other physical urticarias, including cholinergic, solar and aquagenic urticarias, vibratory angioedema, and exercise-induced anaphylaxis.

Therapeutic alternatives for chronic urticaria: an evidence-based review, part 1

OBJECTIVE

To evaluate the use of alternative therapies for chronic urticaria refractory to first-line treatments in an evidence-based manner.

DATA SOURCES

MEDLINE searches were performed cross-referencing urticaria with the names of multiple therapies. Articles were then reviewed for additional citations. Articles published after 1950 were considered.

STUDY SELECTION

All articles, including case reports, were reviewed for soundness and relevance.

RESULTS

Experience has been reported for a wide variety of alternative therapies in the treatment of chronic idiopathic and physical urticarias. Evidence for most agents is limited to anecdotal reports. The second-line therapies reviewed are also categorized based on criteria of safety, efficacy, convenience, and cost, in relation to the first-line antihistamines.

CONCLUSIONS

Alternative agents should be considered in patients with chronic urticaria who are both severely affected and unresponsive to antihistamines. Although monitoring for toxicity is important in management with many alternative agents, safety is favorable compared with corticosteroids.

Management options for patients with aspirin and nonsteroidal antiinflammatory drug sensitivity

OBJECTIVE

To evaluate and provide management strategies for patients with aspirin or nonselective nonsteroidal antiinflammatory drug (NSAID) sensitivity.

DATA SOURCES

Literature retrieval was accessed through MEDLINE (1966-March 2007) using the terms acetaminophen, aspirin, antiinflammatory agents nonsteroidal, urticaria, angioedema, asthma, leukotriene antagonists, desensitization, and tacrolimus. Article references retrieved were hand-searched for other relevant articles.

STUDY SELECTION AND DATA EXTRACTION

All studies published in English were evaluated. Studies, review articles, and commentaries on aspirin-induced asthma and aspirin- or NSAID-induced urticaria/angioedema were included in the review.

DATA SYNTHESIS

Aspirin sensitivity is most often manifested as respiratory reactions (eg, bronchospasm, profuse rhinorrhea, conjunctival injection) or urticaria/angioedema. The primary mechanism is believed to be inhibition of the cyclooxygenase 1 (COX-1) enzyme; as such, patients with aspirin sensitivity often display cross-reactions to nonselective NSAIDs that inhibit the COX-1 enzyme. Management strategies include avoidance of aspirin and cross-reacting nonselective NSAIDs. However, desensitization to aspirin is a viable option for patients with aspirin-induced respiratory reactions, especially for those who require aspirin for thromboembolic prophylaxis. Aspirin desensitization is maintained indefinitely with a daily aspirin dose. There is limited evidence of the use of leukotriene modifiers in preventing aspirin-induced asthma. COX-2 selective NSAIDs, especially in patients with aspirin-induced asthma, have not been found to cross-react. However, approximately 4% of patients with a history of aspirin-induced skin reactions may experience a cutaneous reaction following a challenge to a COX-2 selective NSAID. Since acetaminophen is a weak inhibitor of the COX-1 enzyme, patients with aspirin-induced asthma should not take more than 1000 mg of acetaminophen in a single dose.

CONCLUSIONS

Management of patients with aspirin/NSAID sensitivity includes avoidance of aspirin/nonselective NSAIDs, use of COX-2 selective NSAIDs, acetaminophen in doses less than 1000 mg, and desensitization. The role of leukotriene modifiers requires further study before they can be recommended for patients.

Clinical management of adult patients with a history of nonsteroidal anti-inflammatory drug-induced urticaria/angioedema: update

In the large majority of previous studies, patients with a history of acute urticaria induced by nonsteroidal anti-inflammatory drugs (NSAIDs) seeking safe alternative drugs have undergone tolerance tests uniquely with compounds exerting little or no inhibitory effect on the cyclooxygenase 1 enzyme. In light of recently published studies, however, this approach seems inadequate and should be changed. The present article critically reviews the clinical management of patients presenting with a history of urticaria induced by a single NSAID or multiple NSAIDs and suggests a simple, updated diagnostic algorithm that may assist clinicians in correctly classifying their patients.

Is there a role for antileukotrienes in urticaria?

In vitro and in vivo clinical and experimental data have suggested that leukotrienes play a key role in inflammatory reactions of the skin. Antileukotriene drugs, i.e. leukotriene receptor antagonists and synthesis inhibitors, are a new class of anti-inflammatory drugs that have shown clinical efficacy in the management of asthma. We searched the MedLine database and carried out a manual search on journals specializing in allergy and dermatology for the use of antileukotriene drugs in urticaria. Montelukast might be effective in chronic urticaria associated with aspirin or food additive hypersensitivity or with autoreactivity to intradermal serum injection when taken with an antihistamine but not in moderate chronic idiopathic urticaria. Evidence for the effectiveness of zafirlukast and the 5-lipoxygenase inhibitor, zileuton, in chronic urticaria is mainly anecdotal. In addition, there is anecdotal evidence of effectiveness of antileukotrienes in primary cold urticaria, delayed pressure urticaria and dermographism. No evidence exists for other physical urticarias, including cholinergic, solar and aquagenic urticarias, vibratory angio-oedema, and exercise-induced anaphylaxis.

Emerging drugs for chronic urticaria

Chronic urticaria (CU), with or without angioedema, is a frequent disorder defined as the occurrence of pruritic wheals for > 6 weeks. Studies carried out in the last two decades showed that the origin of the disease is autoimmune in up to 50% of cases. Currently available treatments include antihistamines, corticosteroids and ciclosporin; recently, leukotriene receptor antagonists proved effective in a subset of patients as well. For patients with an unremitting and extremely severe disease unresponsive to standard treatments, plasmapheresis and immunosuppressive drugs have been successfully attempted. Recent findings that the autologous plasma skin test scores positive in nearly all patients and that plasmas from patients with both autoimmune and 'idiopathic' chronic urticaria are frequently characterised by signs of thrombin activation (plasma levels of prothrombin fragment F(1.2) are significantly increased) suggest that clotting cascade might be somehow involved in the pathogenesis of CU. These findings put under a new light some rather sparse studies of the effect of drugs active on the coagulation system (heparin and oral anticoagulants) in patients with CU.

Drug-induced urticaria

Urticaria is characterised by transient swellings of the skin, which fluctuate over hours. Deeper swellings of the subcutaneous and submucosal tissue are known as angio-oedema. Drug-induced urticaria has been reported with a wide range of drugs and vaccines. NSAIDs and antibiotics are the drugs most commonly associated with urticaria, although reliable data from prospectively controlled studies is scarce. Spontaneous reports of drug-induced urticaria to the Committee on Safety of Medicines, UK, over a 40-year period also implicate bupropion, selective serotonin re-uptake inhibitor antidepressants, angiotensin-converting enzyme inhibitors (ACEI), H2 and H1 antihistamines, and systemic antifungals. New evidence suggests that selective COX-2 inhibitors may be tolerated in patients with aspirin-sensitive urticaria. The safety of angiotensin II receptor antagonists in patients with angio-oedema induced by ACEI has not yet been established.

Desloratadine in combination with montelukast in the treatment of chronic urticaria: a randomized, double-blind, placebo-controlled study

BACKGROUND

Chronic urticaria (CU) is a common skin condition. It is frequently a disabling disease due to the persistency of clinical symptoms, the unpredictable course and negative influence on the quality of life.

OBJECTIVE

The aim of this study is to determine whether montelukast, a LTD4 receptor antagonist, plus desloratadine, is more efficacious than desloratadine alone in the treatment of chronic urticaria.

MATERIALS

A randomized, double-blind, placebo-controlled study was conducted on 81 patients with a diagnosis of CU. A 1-week single-blind placebo run-in period (baseline) was followed by a 6-weeks double blind active treatment period. The patients were randomized to receive the following treatment once daily: (a) oral desloratadine (5 mg) plus placebo; (b) desloratadine (5 mg) plus montelukast (10 mg); (c) oral placebo alone. The study ended after another 1-week single-blind placebo washout period.

RESULTS

The evaluable population thus consisted of 76 patients. Both desloratadine alone and desloratadine plus montelukast administered once daily yielded improvements with respect to the baseline assessment as regards pruritus, number of separate episodes, size and number of weals, visual analogue score and patients' quality of life and with respect to the placebo group both in the active treatment period and in the run-out period. However, desloratadine plus montelukast was shown to improve the symptoms and patients' quality of life significantly more than desloratadine alone, although it did not have a significant effect on the number of urticarial episodes.

CONCLUSION

The combination of desloratadine plus montelukast is effective in the treatment of CU. It may therefore be a valid alternative in patients with relatively mild CU, in view of its efficacy and the lack of adverse events.

Advances in the treatment of chronic urticaria

There have been a number of exciting developments in the treatment of allergic diseases in recent years, but the development of new treatments for urticaria has lagged behind. The standard treatment for chronic urticaria (CU) involves the use of H1 antagonists. A number of small but promising studies have found potential benefit with medications that are used less often. This article reviews the established therapies for CU and the experimental evidence for the use of nonstandard and relatively unknown therapies. The potential usefulness of some of the new allergy medications for the treatment of CU also is discussed.

Multiple NSAID intolerance in chronic idiopathic urticaria is correlated with delayed, pronounced and prolonged autoreactivity

Autologous serum skin test (ASST) reactivity is positive in up to 60% of patients with chronic idiopathic urticaria (CIU). About 21 to 30% of patients with CIU have intolerance to acetyl salicylic acid (ASA) and/or other chemically unrelated non-steroidal anti-inflammatory drugs (NSAIDs). To investigate the relationship between ASA/NSAID intolerance and ASST reactivity, a case-control study was performed in 110 patients with CIU and 60 healthy controls. A positive ASST was defined as an erythematous wheal with a diameter of > 5 mm more than the saline-induced response. Patients were assessed at 10-minute intervals for a minimum of three hours. ASA/NSAID intolerance was ascertained by a placebo controlled-provocation test with offending drug (s). Forty-two patients with CIU (38.2%) had autoreactivity whereas only two of the controls (3.3%) displayed early and weak skin responses (P<.0001). ASA/NSAID intolerance was demonstrated in 30 (27.3%) patients with CIU. The prevalences of autoreactivity were 93.3% (28/30) and 17.5% (14/80) in patients with and without ASA/NSAID intolerance, respectively (P<.001). Thirteen of the 25 ASST-positive patients (52%) who had single (n: 7) or multiple (n: 6) NSAID intolerance showed early (before or at 30 min) and mild autoreactivity of short duration, whereas 15 of the remaining 17 ASST-positive patients (88.2%) who all had multiple NSAID intolerance showed delayed (later than 30 min) and prolonged autoreactivity (P<.05). These findings suggest that a common mechanism may be responsible for the pathogeneses of both delayed autoreactivity and multiple NSAID intolerance in CIU. It might be further speculated that delayed, prolonged, and pronounced autoreactivity may be a possible predictor for multiple NSAID sensitivity in CIU.

Recent advances in the management of asthma using leukotriene modifiers

Asthma is a chronic inflammatory disease of the airways that affects approximately 100 million people worldwide. In order to reduce symptoms, improve pulmonary function, and decrease morbidity, current treatment guidelines emphasize the importance of controlling the underlying inflammation in patients with asthma. Leukotrienes are leukocyte-generated lipid mediators that promote airway inflammation. Recognition of the importance of leukotrienes in the pathogenesis of asthma has led to the development of leukotriene modifiers, the first new class of drugs for the treatment of asthma to become available in 25 years. Controlled clinical trials with the four currently used leukotriene modifiers (montelukast, zafirlukast, and zileuton in the US and pranlukast in Japan) have established their efficacy in improving pulmonary function, reducing symptoms, decreasing night-time awakenings, and decreasing the need for rescue medications. They exert anti-inflammatory effects that attenuate cellular infiltration and bronchial hyperresponsiveness and complement the anti-inflammatory properties of inhaled corticosteroids. In patients with moderate and severe asthma, they permit tapering of the corticosteroid dose. In patients with exercise-induced asthma, leukotriene modifiers limit the decline in and quicken the recovery of pulmonary functions without the tolerance issues seen with chronic long-acting beta(2)-adrenoceptor agonist use. In patients with aspirin (acetylsalicylic acid)-induced asthma, they improve pulmonary function and shift the dose response curve to the right, reducing the patient's response to aspirin. In patients with seasonal allergic rhinitis, with or without concomitant asthma, they improve nasal, eye, and throat symptoms as well as quality of life. Leukotriene modifiers are generally safe and well tolerated with adverse effect profiles similar to that of placebo. The one safety issue raised with leukotriene modifiers, Churg-Strauss Syndrome, appears to be the unmasking of an already present syndrome that is manifested when the leukotriene modifiers permit corticosteroid doses to be reduced. Although current treatment guidelines recommend their use in patients with mild persistent asthma, these guidelines were developed just as leukotriene modifiers were coming to the market, before much of the clinical efficacy data were published. Because asthma is a heterogeneous disease, the different asthma phenotypes respond differently to therapies; consequently asthma therapy needs to be individualized. Leukotriene modifiers increase the therapeutic options for patients with asthma and, based on recent data, it is expected that future guidelines will describe expanded uses for these agents in clinical circumstances where these drugs are effective.

Chronic urticaria: a role for newer immunomodulatory drugs?

Chronic urticaria is now recognized as an autoreactive disorder in a substantial fraction of patients. A serologic mediator of whealing has been demonstrated in 50-60% of patients with chronic urticaria, and autoantibodies against the high affinity IgE receptor or IgE have been detected in about half of these patients. The demonstration that chronic urticaria is frequently autoimmune has encouraged a more aggressive therapeutic approach, with the use of immunomodulatory drugs.A step-by-step approach to the management of chronic urticaria is proposed, based on our personal experience and review of current medical literature, identified through Medline research and hand searching in medical journals. The non- or low-sedating H(1) receptor antagonists (antihistamines), such as cetirizine, fexofenadine, loratadine, mizolastine and, more recently, levocetirizine, desloratadine and ebastine, represent the basic therapy for all chronic urticaria patients. Older sedating antihistamines, such as hydroxyzine and diphenhydramine, may be indicated if symptoms are severe, are associated with angioedema, and if the patient is anxious and disturbed at night.Corticosteroid therapy with prednisone or methylprednisolone can be administered for a few days (7-14) if urticarial symptoms are not controlled by antihistamines and a rapid clinical response is needed. In cases of relapse after corticosteroid suspension, leukotriene receptor antagonists, such as montelukast and zafirlukast, should be tried. In our experience, remission of urticarial symptoms can be achieved in 20-50% of chronic urticaria patients unresponsive to antihistamines alone. When urticaria is unremitting and is not controlled by combined therapy with antihistamines and leukotriene receptor antagonists, prolonged corticosteroid therapy may be needed. Long-term corticosteroid therapy should be administered at the lowest dose able to control urticarial symptoms, in order to minimize adverse effects. In a few patients, however, high-dose corticosteroid therapy may have to be administered for long periods. In these patients, immunosuppressive treatment with low-dose cyclosporine can be started. This type of treatment has a corticosteroid-sparing effect and is also generally effective in patients with severe, unremitting urticaria, but requires careful monitoring of cyclosporine plasma concentration and possible adverse effects. Other immunomodulating drugs that have been tried in chronic urticaria patients include hydroxychloroquine, dapsone, sulfasalazine and methotrexate, but their efficacy has not been proven in large controlled studies. Warfarin therapy may also be considered in some patients with chronic urticaria and angioedema unresponsive to antihistamines.

Urticaria and urticarial vasculitis

Urticaria and urticarial vasculitis may be triggered by allergens, infection, autoimmunity and other immunological conditions. Careful evaluation, skin biopsy and specific laboratory tests can assist in diagnosis. The appropriate use of antihistamines, glucocorticoids, and other immunomodulators are discussed.

NSAID-induced urticaria and angioedema: a reappraisal of its clinical management

Hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs), resulting in urticaria and angioedema, is being observed with increasing frequency. Prevalence rates range from 0.1-0.3%, which is partly due to the large size of the exposed (at risk) population. Some predisposing factors for these cutaneous reactions have been identified, among them atopic diathesis, female sex, young adulthood, a history of chronic urticaria and the use of the NSAID for the relief of acute pain. The description of two different arachidonic acid cyclo-oxygenases (COX) about a decade ago, designated COX-1 and COX-2, and the incorporation into the therapeutic armamentarium of more selective enzyme inhibitors for the control of inflammation and pain, has led to an improved understanding of the pathogenesis of adverse reactions to NSAIDs. This has allowed investigators to study 'sensitive' individuals to see if they can safely receive these new pharmaceutical compounds. The reasons why some people react to NSAIDs are not completely clarified. The prevalent theory about the pathogenesis of urticaria and angioedema due to NSAIDs in cross-reactive patients assumes that the inhibition of COX-1 leads to a shunting of arachidonic acid metabolism towards the 5-lipoxygenase pathway, which results in an increased synthesis and release of cysteinyl leukotrienes. Although COX-2 inhibitors are well tolerated by the majority of classic NSAID-sensitive patients, cutaneous reactions to highly selective inhibitors of COX-2 have been described in some of these individuals, casting some doubts about the relevance of such hypotheses. On the other hand, in patients who react to a single NSAID and chemically similar products (single-reactors), specific immunoglobulin E antibodies to haptenated NSAID metabolites have been suspected, although these metabolites are not easily demonstrated by means of routine in vivo or in vitro techniques. Facial (periorbital) angioedema constitutes the most common form of clinical presentation, and one-third of the patients show a mixed clinical pattern of cutaneous (urticaria and/or angioedema) and respiratory symptoms which include upper respiratory tract edema, rhinorrhea, cough, breathlessness and tearing. When necessary, diagnosis is confirmed by means of controlled peroral drug challenges done by experienced physicians in the hospital setting and test results are helpful for clinical management, which will be based on strict avoidance, and the use of alternative tolerated medications. This approach is specially indicated in hypersensitive patients with chronic medical conditions who require continuous NSAID therapy, such as those with arthritis and coronary heart disease.

Aspirin sensitivity and urticaria

The relationship of aspirin sensitivity to urticaria is complex. Aspirin sensitivity can cause acute urticaria in some individuals, aggravate pre-existing chronic urticaria in others or, rarely, act as a cofactor with food or exercise to provoke anaphylaxis. Individuals who react with urticaria appear to come from a different population to those who react with asthma, although there is some overlap. Aspirin-sensitive chronic urticaria patients may also react adversely to some food additives. The pharmacological mechanisms of aspirin-sensitive urticaria are not fully understood but probably involve diversion of arachidonic acid metabolism from prostaglandin to cysteinyl leukotriene formation leading to direct effects on blood vessels and delayed mast cell degranulation with release of histamine. Cross-reactivity amongst all nonsteroidal drugs is common in aspirin-aggravated chronic urticaria but appears not to occur with selective cyclo-oxygenase 2 inhibitors.

Zafirlukast has no beneficial effects in the treatment of chronic urticaria

BACKGROUND

Leukotriene receptor antagonists have shown some efficacy in t he treatment of asthma. Injection of LTC4, LTD4 and LTE4 into the skin leads to a weal-and-flare reaction, suggesting an involvement of leukotrienes in the pathogenesis of urticaria. Indeed, various reports have indicated a beneficial effect for leukotriene receptor antagonists in patients with chronic urticaria.

OBJECTIVE

To determine the therapeutic effect of the leukotriene receptor antagonist zafirlukast in patients with chronic urticaria.

METHODS

The study was a double-blind, placebo-controlled, cross-over study lasting for 12 weeks. Fifty-two patients with chronic urticaria were investigated at a university hospital. The patients were randomized to receive 20 mg zafirlukast b.i.d. or placebo and cross-over was scheduled after 6 weeks. The efficacy of the treatment was evaluated by a daily symptom score, six physical examinations, the requirement of rescue antihistamines (acrivastine) and an overall assessment by the patient andthe investigating physician.

RESULTS

Forty-six patients completed the study: zafirlukast was well tolerated without alteration of the investigated laboratory parameters. In comparison with placebo, treatment with zafirlukast resulted in no significant positive effect for any of the efficacy measures. Moreover, we were unable to identify any subgroup of patients with chronic urticaria responding with a therapeutic benefit.

CONCLUSIONS

The leukotriene receptor antagonist zafirlukast does not provide a significant therapeutic benefit at a dose of 20 mg b.i.d. in patients with chronic urticaria.

Urinary metabolites of histamine and leukotrienes before and after placebo-controlled challenge with ASA and food additives in chronic urticaria patients

BACKGROUND

The recovery of mediator metabolites from urine has the potential to provide a rapid, safe, and easily available index of release of mediators. We aimed to determine urinary metabolites of both histamine and leukotrienes (LTs) in patients affected by chronic urticaria (CU).

METHODS

Twenty patients with CU were studied. They were selected on the basis of double-blind placebo-controlled challenge (DBPC) with acetyl salicylic acid (ASA) and food additives. Ten patients (group B) were negative to both challenges. Ten patients (group C) presented urticaria and/or the appearance of angioedema during or 24 h after challenge, with reactions to ASA (five patients) or food additives (five patients). We recruited 15 healthy volunteers as controls (group A). During a second challenge, groups B and C were challenged double-blind with a single dose of ASA, or a specific food additive, or placebo. The healthy group was challenged only with a placebo (talc capsule). Patients in groups B and C were challenged twice: with placebo (as groups B1 and C1) and with ASA (groups B2 and C2) or food additives (C2). Four samples of urine were collected; one during the night before the specific or sham challenge (baseline), and three at 2, 6 and 24 h after the challenge. Urinary methylhistamine (N-MH) and LTE4 were analyzed and normalized for urinary creatinine.

RESULTS

For urinary N-MH at baseline, there was a significant difference only between group A and groups B1, B2, C1 and C2 (A vs. B1, P < 0.0001; A vs. B2, P < 0.0001; A vs. C1, P < 0.0001; A vs. C2, P < 0.0001). We detected a significant variation in urinary methylhistamine excretion only in group C2 after 2 h, 6 h and 24 h (P < 0.0001). However, no variations were observed in N-MH excretion rate in the other groups (A, B1, C1) after challenge with placebo, and in B2 after challenge with ASA 20 mg. For urinary LTE4 at baseline no differences were found between the mean values for the different groups. After specific challenge, only C2 patients showed significantly increased excretion rates of urinary LTE4 compared with the other groups challenged with placebo (A, B1, C1), or ASA (B2) (P < 0.0001). No significant correlation was seen between urinary LTE4 and methylhistamine excretion rate in any patients.

CONCLUSION

Our results show that urinary excretion of N-MH and LTE4 is different for CU patients without ASA or food hypersensitivity, compared to those with CU with ASA or food additive hypersensitivity after specific challenge.

Evaluating chronic urticaria patients for allergies, infections, or autoimmune disorders

Urticaria is a common disorder affecting one-fifth of the world's population. The pathophysiology is characterized by an increased propensity for mast cell degranulation with the release of potent mediators into the dermal and subdermal tissues with resulting vasoactive, chemotactic, and inflammatory effects. The final clinical manifestation of the typical urticarial lesion is the effect of several diverse effects and causes. The general classification is acute, chronic, and physical urticaria. In general, allergenic triggers can be identified in between 60-80% of acute urticarias. Physical urticarias are characterized by the onset after the specific inciting stimulus, which can reproduce the characteristic lesion which is usually of shorter duration (with the exception of delayed pressure urticaria). Chronic idiopathic urticaria is associated with thyroid autoimmunity and, more recently, anti-mast cell receptor antibodies. An extensive work-up is usually not indicated or helpful in identifying a cause. Food or other allergens are rare causes of this type of presentation. The evaluation and work-up is dependent on clues identified by history. The treatment is removal of specific and non-specific triggers and the use of symptomatic medications generally attenuating the mediator effects.

The leukotriene receptor antagonist montelukast in the treatment of chronic idiopathic urticaria: a single-blind, placebo-controlled, crossover clinical study

BACKGROUND

Chronic idiopathic urticaria (CIU) might be refractory to standard therapies. For the patients with severe unremitting CIU who have failed to benefit from conventional therapy with antihistamines, other effective and safe therapeutic modalities are required.

OBJECTIVE

A randomized, single-blind, placebo-controlled crossover study was conducted to evaluate the efficacy and safety of the new selective leukotriene antagonist montelukast sodium in the treatment of refractory CIU.

METHODS

Thirty patients with refractory CIU were enrolled in the trial. After informed consent was obtained, patients were randomly assigned to 2 groups. The patients in group A received 10 mg/d montelukast and a nonsedating H(1) antihistamine (cetirizine) when needed for 6 weeks. After a 2-week washout period, they received placebo for 6 weeks and the same H(1) antihistamine as needed. Group B received the treatment vice versa. Improvement was monitored by using the self-estimated urticaria activity score, which is the sum of the wheal number score and the itch severity score, and the antihistamine counts used in each study period.

RESULTS

More significant decreases occurred in urticaria activity scores with montelukast therapy compared with those with placebo therapy (P <.001). H(1) antihistamine use was also significantly less frequent during the montelukast period (P <.001). There were no significant side effects with montelukast therapy.

CONCLUSION

The present study results suggest that montelukast might be an effective and safe therapeutic agent in the treatment of refractory CIU.

Safety of selective cyclooxygenase-2 inhibitor rofecoxib in patients with NSAID-induced cutaneous reactions

BACKGROUND

Controlled oral challenge with nonsteroidal anti-inflammatory drugs (NSAIDs) is the only definite way to diagnose the different clinical manifestations of NSAID sensitivity.

OBJECTIVE

To evaluate the safety of selective cyclooxygenase-2 inhibitor rofecoxib in a patient population with NSAID-induced skin reactions.

METHODS

We prospectively conducted single-blind, placebo-controlled, oral challenges (SBPCOCs) with rofecoxib in 15 patients with challenge-proven NSAID-induced cutaneous reactions.

RESULTS

Fifteen patients (9 men and 6 women, ranging in age from 14 to 60 years) had positive SBPCOC response to at least one of the following NSAIDs: aspirin (in 46.7% of cases), nimesulide (in 40% of cases), and diclofenac (in the remaining 13.3% of cases). During controlled challenges, 8 patients (53.3%) had urticaria (1 of them with associated angioedema); 6 (40%) had facial angioedema; and 1 (6.6%) had nonurticarial rash. Controlled oral challenge with rofecoxib were well tolerated in all patients.

CONCLUSION

Rofecoxib did not cross-react with aspirin and other NSAIDs in patient with NSAID-induced skin reactions. A tolerance observed to this drug during SBPCOCs will indicate a safe alternative in this patient-group.

Autoreactivity is highly prevalent in patients with multiple intolerances to NSAIDs

BACKGROUND

A subset of drug-allergic patients show a marked propensity to react against several, chemically unrelated nonsteroidal anti-inflammatory drugs (NSAIDs). The pathogenesis of such multiple drug reactions is unclear. Approximately 30% of patients with chronic idiopathic urticaria, a condition frequently characterized by autoreactivity on autologous serum skin test (ASST), experience flares of hives after taking chemically unrelated NSAIDs.

OBJECTIVE

To detect whether a clinically unapparent autoreactivity may represent the nonspecific mechanism facilitating drug-induced histamine release in patients with a history of urticaria/angioedema induced by several, chemically unrelated NSAIDs.

METHODS

Thirty-six adults with a history of acute NSAID-induced urticaria (22 with multiple NSAID sensitivity [MNS]; 14 with single NSAID sensitivity [SNS]; and 20 atopic controls without a history of drug allergy) underwent ASST. Sera from 14 MNS and 4 SNS subjects (all ASST-positive) underwent histamine release assay with basophils from normal donors. Sera from five MNS patients were tested on autologous basophils as well.

RESULTS

Twenty of 22 (91%) MNS subjects versus 5 of 14 (36%) SNS subjects were positive on ASST (P < 0.01). No atopic control was ASST-positive. Sera from 4 of 14 (29%) MNS patients versus 0/4 SNS subjects (P = NS) induced significant histamine release from basophils of normal donors. The use of autologous basophils did not significantly change these results.

CONCLUSION

Most patients with multiple NSAID intolerance and approximately one-third of those with single NSAID hypersensitivity are characterized by the presence of circulating histamine-releasing factors. Their nature is still unclear, but the fact that only a minority of sera from ASST+ subjects were able to induce histamine release from normal basophils in vitro suggests that these factors might not differ from those involved in most patients with chronic urticaria. These factors might play a relevant pathogenic role in NSAID-induced urticaria reactions.

Drug-induced angioedema without urticaria

Angioedema without urticaria is a clinical syndrome characterised by self-limiting local swellings involving the deeper cutaneous and mucosa tissue layers. Most occurrences of angioedema respond to treatment with a histamine H1 receptor blocker (antihistamine) because they are an allergic or parallergic reaction. A small number of cases do not respond to antihistamine treatment. Such cases tend to occur in patients with deficiency or dysfunction of the inhibitor of the first component of the complement (C1-INH), but more rarely can occur in patients with other conditions and as an adverse drug reaction. Angioedema is well documented in patients taking ACE inhibitors. Considering that 35 to 40 million patients are treated worldwide with ACE inhibitors, this drug class could account for several hundred deaths per year from laryngeal oedema. ACE inhibitors certainly do not mediate angioedema through an allergic or idiosyncratic reaction. For this reason the relationship with this drug is often missed and consequently quite underestimated. Rare instances of angioedema have also been reported with angiotensin II receptor antagonists. This adverse effect seems to occur less frequently with angiotensin II receptor antagonists than with ACE inhibitors. However, we do not know whether this adverse effect has the same mechanism with the 2 classes of medications. Some cases of severe angioedema have been recently reported after treatment with fibrinolytic agents. Scattered reports suggest the possibility of angioedema associated with the use of estrogens, antihypertensive drugs other than ACE inhibitors, and psychotropic drugs. Angioedema can also occur with nonsteroidal anti-inflammatory drugs. Prevention of angioedema relies first on the patient history. Estrogen and ACE inhibitors should be avoided in a patient with congenital or acquired C1-INH deficiency. In the case of ACE inhibitors, the appearance of angioedema following long term treatment does not lessen the probability that such an agent could be the cause. The most important action to take in a patient with suspected drug-induced angioedema is to discontinue the pharmacological agent. Epinephrine (adrenaline), diphenydramine and intravenous methylprednisolone have been proposed for the medical management of airway obstruction, but so far no controlled studies have demonstrated their efficacy. If the acute airway obstruction leads to life-threatening respiratory compromise an emergency cricothyroidotomy must be performed.

Pathophysiological role of leukotrienes in dermatological diseases: potential therapeutic implications

In vitro and in vivo data have demonstrated that leukotrienes play a key role not only in allergic airway diseases but also in inflammatory reactions of the skin. Antileukotriene drugs, i.e. leukotriene receptor antagonists and synthesis inhibitors, are a new class of anti-inflammatory drugs that have shown clinical efficacy in the management of asthma, allergic rhinitis and inflammatory bowel disease. To address the question of the validity and applicability of published evidence of the use of antileukotriene drugs in dermatological diseases, we reviewed data concerning the pathophysiological effect of leukotrienes in the skin and in skin diseases, and the experience with antileukotriene treatment that has been published. In vivo and in vitro data suggest that antileukotriene treatment may have efficacy in atopic dermatitis, different types of urticaria or psoriasis and other skin diseases such as bullous skin diseases, collagenoses, Sjogren-Larsson syndrome or Kawasaki disease. Nevertheless, published evidence is very limited and before any conclusions can be drawn, additional basic research needs to be performed with regard to the role of different leukotrienes and leukotriene receptors in skin diseases. On the basis of these data, randomised and placebo-controlled clinical trials with leukotriene antagonists and synthesis inhibitors should be performed. Moreover, future studies investigating the additive benefit of antileukotriene drugs are warranted, e.g. in combination with antihistamines, corticosteroids or other anti-inflammatory drugs.

LTC4-synthase A-444C polymorphism: lack of association with NSAID-induced isolated periorbital angioedema in a Spanish population

BACKGROUND

The mechanism of nonsteroidal anti-inflammatory drug (NSAID)-induced reactions is unknown. However, strong evidence supports the hypothesis of an enhanced production of cysteinyl-leukotrienes. The existence of a polymorphism (A-444C) in the promoter region of the leukotriene (LT)C4-synthase gene (the terminal enzyme in the LTC4 production pathway) has been reported. This polymorphism has yielded contradictory results on its association with aspirin-induced asthma.

OBJECTIVE

The present study was designed to investigate the possible genetic association of C(-444) allele and a specific clinical phenotype of NSAID sensitivity, the NSAID-induced isolated periorbital angioedema, via a case/control study.

METHODS

The polymorphism A-444C was analyzed in 58 patients with NSAID-induced periorbital angioedema and 61 control subjects, who had undergone single-blind, placebo-controlled oral challenge. Genotype was determined by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

We have not found an association of C(-444), allele with NSAID-induced isolated periorbital angioedema.

CONCLUSIONS

Further studies are needed to determine whether polymorphisms in the LTC4-synthase gene or other leukotriene-forming enzymes are involved in the pathogenesis of the different subsets of NSAID sensitivity.

NSAID intolerance in chronic idiopathic urticaria: A study of its relationship with histamine-releasing activity of patients' sera

BACKGROUND

about one fourth of patients with chronic idiopathic urticaria (CIU) experience flares of hives after taking chemically unrelated nonsteroidal anti-inflammatory drugs (NSAID). The reasons for such intolerance are still elusive.

OBJECTIVE

this study aimed to investigate NSAID intolerance in patients with CIU in view of the in vivo and in vitro histamine releasing activity of their sera.

METHODS

117 adults (M/F 41/76) with CIU underwent intradermal test with autologous serum, and the ability of their sera to induce histamine release from normal blood donors was evaluated. NSAID intolerance was ascertained by careful interview.

RESULTS

overall, 32/117 (27 %) patients reported NSAID intolerance. The prevalence on NSAID intolerance did not differ in the three subgroups: negative on both in vivo and in vitro tests (9/36; 25 %), positive or intradermal test but negative on basophil histamine release assay (16/58; 28 %), or positive on both in vivo and in vitro tests (7/23; 30 %).

CONCLUSION

in patients with CIU intolerance to NSAID does not depend on the mechanism of histamine release.