An international Delphi study on the burden of allergic rhinoconjunctivitis and urticaria and the role of bilastine among current treatment options

BACKGROUND

allergic rhinoconjunctivitis and chronic urticaria are common histamine-driven diseases, exerting detrimental effects on cognitive functions, sleep, daily activities and quality of life. Non-sedating second-generation H₁-antihistamines are the first line treatment of choice. Aim of the study was to define the role of bilastine among second-generation H₁-antihistamines in the treatment of allergic rhinoconjunctivitis and urticaria in patients of different ages.

METHODS

an international Delphi study was carried out to assess consensus among experts from 17 European and extra-European countries on three main topics: 1) Burden of disease; 2) Current treatment options; 3) Specific characteristics of bilastine among second generation antihistamines.

RESULTS

here, we present the results obtained for a selection of 15 out of 27 consensus statements, focused on disease burden, role of second-generation antihistamines and bilastine profile. The rate of concordance was ≥ 98% for 4 statements, ≥ 96% for 6, ≥ 94% for 3, and ≥ 90% for 2.

CONCLUSIONS

the high degree of agreement obtained suggests a wide awareness of the burden of allergic rhinoconjunctivitis and chronic urticaria among experts from all over the world and reflect a broad consensus on the role of second generation antihistamines in general and of bilastine in particular for their management.

Interleukin-17 is a potential player and treatment target in severe chronic spontaneous urticaria

BACKGROUND

Chronic spontaneous urticaria (CSU) is considered an autoimmune disorder in 50% of cases at least, in which T- and mast cell mediators are considered to be the primary cause of symptoms. However, H₁ -antihistamines, cyclosporine A, and omalizumab fail to achieve complete symptom amelioration in up to 70% of patients. This suggests that other inflammatory pathways are involved and that additional and more effective treatments need to be developed.

OBJECTIVE

This preliminary report examines the possibility that interleukin-17 (IL-17), a cytokine involved in the pathogenesis of many autoimmune diseases, may contribute to CSU and its inhibition may offer a relevant therapeutic target.

METHODS

The expression of IL-17A in skin biopsies of 20 CSU patients and 10 healthy controls was determined by quantitative histomorphometry. We also assessed the response to secukinumab (anti-IL-17A) treatment patients of eight severe CSU (7-day urticaria activity score UAS7 32-40) who were H₁ -antihistamine and omalizumab-resistant.

RESULTS

Increased numbers of CD4+ T cells and mast cells were present in both lesional and non-lesional skin of CSU patients compared with healthy controls. Both types of cells were strongly positive for IL-17A and found to be in close proximity to each other. All eight patients treated with the anti-IL-17A antibody, secukinumab, showed significant improvement in CSU disease activity. The action of secukinumab was shown to be relatively slow in onset. The significant reduction in disease activity from baseline UAS7 was demonstrated to be 55% and 82% at 30 and 90 days, respectively.

CONCLUSIONS

These findings suggest that IL-17 is involved in the pathogenesis of CSU and that IL-17 should be investigated as a therapeutic target in future studies with larger numbers of patients.

Characterization of cowhage-induced pruritus in inflamed and non-inflamed skin

BACKGROUND AND OBJECTIVE

Pruritus is a major symptom of many inflammatory diseases and impacts greatly the quality of life in patients. We aimed to specify the characteristics of experimentally induced pruritus in normal skin and in experimentally induced inflammatory dermatitis in healthy volunteers.

METHODS

Skin inflammation was induced by the repeated application of sodium lauryl sulphate (SLS 2%) on the volar forearms of 30 healthy volunteers. Inflammatory dermatitis intensity was assessed using the eczema score adapted from Frosch and Kligman. Non-histaminergic pruritus was induced by cowhage spicules rubbed on the volar forearms and recorded for 30 min on a 10-cm visual analogue scale (VAS) in both non-inflamed and inflamed skin.

RESULTS

Induction of inflammatory dermatitis by SLS resulted in a mild inflammatory dermatitis with an inflammation score of 2.3 ± 0.1 within 7 days of treatment. Cowhage-induced pruritus was of markedly higher intensity (P < 0.001), and all but two individuals had higher maximum pruritus intensity in inflamed skin as compared to non-inflamed skin, whereas the kinetics of the pruritus response were similar. The quality of cowhage-induced pruritus was significantly different with more 'burning' and 'painful sensations' in inflamed skin (P < 0.01). Maximum pruritus intensity in inflamed skin strongly correlated with maximum pruritus intensity in non-inflamed skin (r = 0.51, P = 0.004). Skin hydration, skin barrier integrity and dermatitis severity did not correlate with pruritus intensity.

CONCLUSION

Taken together, pruritus in inflamed skin is perceived as more intense, painful and burning. This may explain, in part, why pruritus is a major driver of quality-of-life impairment in patients with chronic inflammatory skin conditions such as atopic dermatitis.

The EAACI/GA²LEN/EDF/WAO guideline for the definition, classification, diagnosis and management of urticaria

This evidence- and consensus-based guideline was developed following the methods recommended by Cochrane and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group. The conference was held on 1 December 2016. It is a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the EU-founded network of excellence, the Global Allergy and Asthma European Network (GA²LEN), the European Dermatology Forum (EDF) and the World Allergy Organization (WAO) with the participation of 48 delegates of 42 national and international societies. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS). Urticaria is a frequent, mast cell-driven disease, presenting with wheals, angioedema, or both. The lifetime prevalence for acute urticaria is approximately 20%. Chronic spontaneous urticaria and other chronic forms of urticaria are disabling, impair quality of life and affect performance at work and school. This guideline covers the definition and classification of urticaria, taking into account the recent progress in identifying its causes, eliciting factors and pathomechanisms. In addition, it outlines evidence-based diagnostic and therapeutic approaches for the different subtypes of urticaria.

Potential blood biomarkers in chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is a mast cell-driven disease that is defined as the recurrence of weals, angioedema or both for > 6 weeks due to known or unknown causes. As of yet, disease diagnosis is purely clinical. Objective tools are needed to monitor the activity of CSU and the efficacy of treatment. Recently, several reports have suggested that blood parameters may be considered as potential disease-related biomarkers. Here, we reviewed available literature on blood biomarkers for CSU diagnosis, activity monitoring, duration, patient subgroup allocation or response to treatment. We performed a PubMed, Google Scholar and Web of Science search and identified and analysed 151 reports published prior to January 2016. We found strong evidence for significant differences between patients with CSU and healthy controls in blood levels or values of D-dimer, C-reactive protein (CRP), matrix metalloproteinase-9 (MMP-9), mean platelet volume (MPV), factor VIIa, prothrombin fragment 1 + 2 (F1 + 2), tumour necrosis factor, dehydroepiandrosterone sulphate and vitamin D. Also, there is strong evidence for a significant association between CSU activity and blood levels or values of D-dimer, F1 + 2, CRP, IL-6 and MPV. Strong evidence for reduced basophil count and high levels of IgG anti-FcεRI in the subgroup of CSU patients with positive autologous serum skin test was shown. In contrast, the evidence for all reported blood biomarkers for differentiating CSU from other diseases, or a role in prognosis, is weak, inconsistent or non-existent. Taken together, we identified 10 biomarkers that are supported by strong evidence for distinguishing patients with CSU from healthy controls, or for measuring CSU activity. There is a need for further research to identify biomarkers that predict outcome or treatment response in CSU.

Bilastine: a new H1 -antihistamine with an optimal profile for updosing in urticaria

This review set out to examine published papers detailing the efficacy of bilastine in skin models and urticaria to assess whether it meets the optimal profile for updosing in urticaria, that is, strong clinical efficacy and freedom from unwanted side effects, particularly sedation. Bilastine is a highly effective H₁ -antihistamine even when used at the basic dose of 20 mg daily. Its facilitated uptake after oral dosage gives it a rapid onset and long duration of action. In both wheal and flare studies and in urticaria updosing fourfold showed increased effectiveness. With respect to somnolence, bilastine is a substrate for P-glycoprotein, a membrane pump which prevents it crossing the blood-brain barrier. Consequently, bilastine is a practically 'non-sedating' H₁ -antihistamine. In conclusion, the excellent profile of bilastine in both efficacy and safety make it the ideal H₁ -antihistamine for updosing the daily dose fourfold in difficult-to-treat urticaria as recommended by the EAACI/GA² LEN/EDF/WAO guideline for the management of urticaria.

Questions and answers in chronic urticaria: where do we stand and where do we go?

This supplement reports proceedings of the second international Global Urticaria Forum, which was held in Berlin, Germany in November 2015. In 2011, a report of the GA(2) LEN task force on urticaria outlined important and unanswered questions in chronic urticaria (CU). These included, but were not limited to, questions on the epidemiology and course of chronic spontaneous urticaria (CSU) [also called chronic idiopathic urticaria (CIU)], the resources allocated for the diagnosis and treatment of CSU, whether patients with angioedema as an isolated symptom can be regarded as a subgroup of CSU, and the efficacy and long-term safety of therapies. Many of these questions have been addressed by recent studies. Some of the answers obtained raise new questions. Here, we summarize some of the key insights on CU obtained over recent years, and we discuss old and new unmet needs and how to address them with future studies. We need to analyze the influence of recent advances in understanding of the burden of CU on patients and society, disease management and the CU patient journey. Our increased understanding of urticarial pathophysiology and consideration of the patient as a whole will need to be translated to better treatment algorithms and protocols. Actions to address these challenges include the 5th International Consensus Meeting on Urticaria, which will take place later this year. The formation of a global network of Urticaria Centers of Reference and Excellence over the next few years has also been proposed, with the aim of providing consistent excellence in urticaria management and a clear referral route, furthering knowledge of urticaria through additional research and educating/promoting awareness of urticaria.

Skin provocation tests may help to diagnose atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common skin disorder. Its diagnosis relies on clinical judgment. Mild and untypical manifestations may cause diagnostic difficulties. Biomarkers for the differential diagnostic workup of AD are needed.

OBJECTIVE

To test whether the results of skin provocation with cowhage, an established model of histamine-independent pruritus, and histamine are different in AD patients and healthy subjects and whether these tests may be used as diagnostic markers of AD.

METHODS

Twenty-two AD patients and 18 healthy controls were subjected to topical cowhage provocation and skin prick testing with histamine and assessed for differences in the quality, intensity, and persistence of itch, for wheal diameter, volume, and flare size and intensity.

RESULTS

Patients with AD, compared with healthy controls, exhibited significantly smaller histamine-induced flares (P < 0.01) and markedly longer itch persistence after provocation with cowhage (P < 0.01). Both parameters showed good diagnostic properties for AD (area under the receiver operating characteristic (ROC) curve 0.78 and 0.80, respectively). The persistence of cowhage-induced itch for at least 30 min and a histamine-induced flare of less than 2 cm in diameter were reliable thresholds for the diagnosis of AD. If combinations of the results of both tests were used, their sensitivity and specificity of diagnosing AD were up to 91% and 94%, respectively.

CONCLUSION

The clinical benefit of cowhage and histamine skin provocation tests should be investigated in further studies. Long persistence of cowhage-induced itch and diminished histamine-induced flare in nonlesional skin may support diagnosis of AD.

Definition, aims, and implementation of GA(2) LEN Urticaria Centers of Reference and Excellence

BACKGROUND

GA²LEN, the Global Allergy and Asthma European Network, has recently launched a program for the development, interaction, and accreditation of centers of reference and excellence in special areas of allergy embedded in its overall quality management of allergy centers of excellence. The first area chosen is urticaria. Urticaria is a common and debilitating condition and can be a challenge for both patients and treating physicians, especially when chronic. Centers of reference and excellence in urticaria (UCAREs) can help to improve the management of hard-to-treat conditions such as urticaria.

AIMS

Here, we describe the aims, the requirements and deliverables, the application process, and the audit and accreditation protocol for GA²LEN UCAREs.

RESULTS

The main aims of GA²LEN UCAREs are to provide excellence in urticaria management, to increase the knowledge of urticaria by research and education, and to promote the awareness of urticaria by advocacy activities. To become a certified GA²LEN UCARE, urticaria centers have to apply and fulfill 32 requirements, defined by specific deliverables that are assessed during an audit visit.

DISCUSSION AND CONCLUSION

The GA²LEN UCARE program will result in a strong network of urticaria specialists, promote urticaria research, and harmonize and improve urticaria management globally.

Atopic predisposition in cholinergic urticaria patients and its implications

BACKGROUND

Cholinergic urticaria (CholU) is a frequent chronic urticaria disorder with itchy weal and flare-type skin reactions in response to physical exercise or passive warming. A higher frequency of atopy among CholU patients has been reported, but the significance of this observation is unclear.

OBJECTIVE

To assess the prevalence and relevance of atopy in CholU patients.

MATERIALS AND METHODS

Thirty CholU patients were assessed for atopic skin diathesis (atopic predisposition) by use of the Erlangen Atopy Score and divided into atopic and non-atopic predisposed CholU individuals. Both groups were assessed for disease severity (CholUSI) and activity (CholUAS7), quality of life impairment [Dermatology Life Quality Index (DLQI) and CU-Q₂ OL], seasonal exacerbation, total and specific serum IgE and comorbidities.

RESULTS

CholU patients were found to exhibit high rates of atopic predisposition (57%), with higher prevalence and scores in female than in male patients. High Erlangen Atopy Scores were linked to high CholU severity, activity and impact on QoL. Atopic predisposed CholU patients show different seasonal exacerbation patterns, IgE specificity and comorbidity profiles as compared to non-atopic CholU patients.

CONCLUSION

Atopic predisposition and cholinergic urticaria appear to be linked more closely than previously thought, which suggests shared pathogenetic mechanisms. Atopic patients with cholinergic urticaria have more severe disease and poorer quality of life than those who do not. Thus, all cholinergic urticaria patients should be assessed for atopic predisposition.

Development and validation of the mastocytosis quality of life questionnaire: MC-QoL

BACKGROUND

Mastocytosis is a heterogeneous disease characterized by a clonal expansion of mast cells in various organs. The vast majority of patients affected suffer from signs and symptoms caused by mediator release from mast cells. Although the disease burden is high, there is currently no specific instrument to measure health-related quality of life (HRQoL) impairment in patients with mastocytosis.

OBJECTIVE

The aim of this study was to develop and validate a disease-specific tool to assess HRQoL impairment in patients with cutaneous and indolent systemic mastocytosis, the Mastocytosis Quality of Life Questionnaire (MC-QoL).

METHODS

Sixty-two potential MC-QoL items were developed in a combined approach consisting of semi-structured patient interviews, expert input and literature research. Item selection was performed by impact analysis with 76 patients and a final review for face validity. The resulting MC-QoL was tested for validity, reliability and influence factors. In parallel, an US American-English version of the MC-QoL was developed.

RESULTS

A total of 158 patients (41 CM, 41 MIS and 76 ISM) took part in the MC-QoL validation study. The final 27-item questionnaire was found to have a four-domain structure ('symptoms', 'emotions', 'social life/functioning' and 'skin'), a valid total score and an excellent test-retest reliability. Multiple regression analysis revealed disease duration, but not age, gender or skin involvement to be a significant determinant of HRQoL impairment in mastocytosis.

CONCLUSIONS

The MC-QoL is the first disease-specific HRQoL questionnaire for adult patients with cutaneous and indolent systemic mastocytosis. This short, validated and reliable instrument will serve as a valuable tool in future clinical studies and in routine patient care.

Economic burden of inadequate management of allergic diseases in the European Union: a GA(2) LEN review

BACKGROUND

In the European Union (EU), between 44 and 76 million individuals of the 217 million EU employees suffer from allergic disease of the airways or the skin. Up to 90% of these persons are untreated or insufficiently treated. This has major socio-economic consequences such as absence from work (absenteeism), particularly reduced productivity at work (presenteeism).

METHODS

We used published literature and online statistical information from Eurostat and Eurofound to assess the costs of allergic disease to society.

RESULTS

Allergies have an impact on direct, indirect, intangible and opportunity costs. Most importantly, for the EU, avoidable indirect costs per patient insufficiently treated for allergy range between €55 and €151 billion per annum due to absenteeism and presenteeism, that is, €2405 per untreated patient per year. On the other hand, appropriate therapy for allergic diseases is available at comparatively low costs at an average of €125 per patient annually, equalling only 5% of the costs of untreated disease, allowing potential savings of up to €142 billion.

CONCLUSIONS

A better care for allergies based on guideline-based treatment would allow Europe's economy substantial savings. In addition, allergies have an impact on learning and performance at school and university, leading to opportunity costs for society. This cannot be calculated moneywise but will have an impact in a modern knowledge-based society. Still allergies are trivialized in society, noting that the costs of therapy are paid by patients and healthcare services, whereas economic savings are made by employers and society. A change of this mindset is urgently needed.

Interleukin-33 promotes the proliferation of mouse mast cells through ST2/MyD88 and p38 MAPK-dependent and Kit-independent pathways

Interleukin-33 (IL-33), a member of the IL-1 cytokine family, is emerging as a new modulator of immune and inflammatory responses. Although IL-33 and its associated receptor ST2 are reportedly expressed in mast cells (MCs), the precise role of IL-33 in modulating MC function has not been determined. In the present studies, we explored IL-33 effects on MCs in vivo and in vitro. IL-33 increased the number of peritoneal and skin MCs in vivo. IL-33 also resulted in increased proliferation of MCs in vitro, as explored by WST assay. Cell cycle analysis further confirmed this result by showing increased G2 cell populations in MCs stimulated with IL-33. We found that IL-33-mediated MC proliferation requires ST2 and MyD88, is independent of Kit, and is mediated through a p38 MAPK-dependent pathway. IL-33 did not induce degranulation and was not cytotoxic for MCs. This novel mechanism for increasing MC proliferation and numbers further defines the role of IL-33 in MC-dependent diseases including allergies and may help to develop novel approaches for the treatment of these disorders.

An improved Peltier effect-based instrument for critical temperature threshold measurement in cold- and heat-induced urticaria

BACKGROUND

Cold- and heat-induced urticaria are chronic physical urticaria conditions in which wheals, angioedema or both are evoked by skin exposure to cold and heat respectively. The diagnostic work up of both conditions should include skin provocation tests and accurate determination of critical temperature thresholds (CTT) for producing symptoms in order to be able to predict the potential risk that each individual patient faces and how this may be ameliorated by therapy.

OBJECTIVE

To develop and validate TempTest(®) 4, a simple and relatively inexpensive instrument for the accurate determination of CTT which may be used in clinical practice.

METHODS

TempTest(®) 4 has a single 2 mm wide 350 mm U-shaped Peltier element generating a temperature gradient from 4 °C to 44 °C along its length. Using a clear plastic guide placed over the skin after provocation, CTT values may be determined with an accuracy of ±1 °C. Here, TempTest(®) 4 was compared with its much more expensive predecessor, TempTest(®) 3, in inducing wheals in 30 cold urticaria patients.

RESULTS

Both TempTest(®) 4 and TempTest(®) 3 induced wheals in all 30 patients between 8 ° and 28 °C. There was a highly significant (P < 0.0001) correlation between the instruments in the CTT values in individual patients.

CONCLUSION

The TempTest(®) 4 is a simple, easy to use, licensed, commercially available and affordable instrument for the determination of CTTs in both cold- and heat-induced urticaria.

Symptomatic dermographism: an inadequately described disease

BACKGROUND

Symptomatic dermographism is the most common form of physical urticaria with a prevalence of 2-5%. However, its clinical picture has rarely been described.

OBJECTIVE

To understand more of patients' views about the practical aspects of their condition, its cause and impact on quality of life.

METHODS

Ninety-one of 150 patients with symptomatic dermographism from our specialist urticaria clinic completed a 38-question questionnaire sent them by mail.

RESULTS

The mean duration of disease was 6¼ years. In most patients, the condition was continuous, but ~25% had prolonged symptom-free phases. Severity was evaluated as moderate in 45%, severe in 33% and very severe in 6% of respondents. Other responses included: symptoms worse in the evening in 81%; quality of life significantly impaired in 44%; normal life not possible 7%; stress induces acute episodes 44%; other urticarial forms coexist 21%; allergy coexist 48%. A family history was reported in 14%. Almost all patients were taking H1 -anti-histamines, 49% getting marked improvement and 23% becoming symptoms free.

LIMITATIONS

It is a survey only of patient opinions.

CONCLUSIONS

This questionnaire survey confirmed that symptomatic dermographism is a debilitating condition with profound effects on quality of life but its underlying cause and disease mechanisms remain obscure.

Methods report on the development of the 2013 revision and update of the EAACI/GA2 LEN/EDF/WAO guideline for the definition, classification, diagnosis, and management of urticaria

This methods report describes the process of guideline development in detail. It is the result of a systematic literature review using the 'Grading of Recommendations Assessment, Development and Evaluation' (GRADE) methodology and a structured consensus conference held on 28 and 29 November 2012, in Berlin. It is a joint initiative of the Dermatology Section of the European Academy of Allergy and Clinical Immunology (EAACI), the EU-funded network of excellence, the Global Allergy and Asthma European Network (GA(2) LEN), the European Dermatology Forum (EDF), and the World Allergy Organization (WAO) with the participation of delegates of 21 national and international societies. This guideline covers the definition and classification of urticaria, taking into account the recent progress in identifying its causes, eliciting factors and pathomechanisms. In addition, it outlines evidence-based diagnostic and therapeutic approaches for the different subtypes of urticaria. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS) and is published in Allergy 2014; 69:868-887.

The EAACI/GA(2) LEN/EDF/WAO Guideline for the definition, classification, diagnosis, and management of urticaria: the 2013 revision and update

This guideline is the result of a systematic literature review using the 'Grading of Recommendations Assessment, Development and Evaluation' (GRADE) methodology and a structured consensus conference held on 28 and 29 November 2012, in Berlin. It is a joint initiative of the Dermatology Section of the European Academy of Allergy and Clinical Immunology (EAACI), the EU-funded network of excellence, the Global Allergy and Asthma European Network (GA(2) LEN), the European Dermatology Forum (EDF), and the World Allergy Organization (WAO) with the participation of delegates of 21 national and international societies. Urticaria is a frequent, mast cell-driven disease, presenting with wheals, angioedema, or both. The life-time prevalence for acute urticaria is approximately 20%. Chronic spontaneous urticaria and other chronic forms of urticaria do not only cause a decrease in quality of life, but also affect performance at work and school and, as such, are members of the group of severe allergic diseases. This guideline covers the definition and classification of urticaria, taking into account the recent progress in identifying its causes, eliciting factors and pathomechanisms. In addition, it outlines evidence-based diagnostic and therapeutic approaches for the different subtypes of urticaria. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS).

Night-time sedating H1 -antihistamine increases daytime somnolence but not treatment efficacy in chronic spontaneous urticaria: a randomized controlled trial

Background

Many physicians believe that the most effective way to treat chronic urticaria is to take a nonsedating second-generation H₁-antihistamine in the morning and a sedating first-generation H₁-antihistamine, usually hydroxyzine, at night to enhance sleep. But is this belief well founded?

Objectives

To test this belief by comparing the effectiveness and prevalence of unwanted sedative effects when treating patients with chronic spontaneous urticaria (CSU) with levocetirizine 15 mg daily plus hydroxyzine 50 mg at night (levocetirizine plus hydroxyzine) vs. levocetirizine 20 mg daily (levocetirizine monotherapy).

Methods

In this randomized, double-blind, cross-over study, 24 patients with difficult-to-treat CSU took levocetirizine plus hydroxyzine or levocetirizine monotherapy for periods of 5 days each. At the end of each treatment period, assessments were made of quality of life (Chronic Urticaria Quality of Life Questionnaire, CU-Q₂oL), severity of urticaria symptoms (Urticaria Activity Score, UAS), sleep disturbance during the night and daytime somnolence.

Results

Both treatments significantly decreased UAS, night-time sleep disturbances and CU-Q₂oL scores (P < 0·001) without significant differences between the two. Compared with baseline, daytime somnolence was significantly reduced by levocetirizine monotherapy (P = 0·006) but not by levocetirizine plus hydroxyzine (P = 0·218). Direct comparison of the two treatment modalities in terms of daytime somnolence favoured levocetirizine monotherapy (P = 0·026).

Conclusions

The widespread belief that sleep is aided by the addition of a sedating first-generation H₁-antihistamine, usually hydroxyzine, at night is not supported. These results are in line with the urticaria guidelines, which state that first-line treatment for urticaria should be new-generation, nonsedating H₁-antihistamines only.

Up-dosing with bilastine results in improved effectiveness in cold contact urticaria

Background

Cold contact urticaria (CCU) is characterized by itchy wheal and flare responses due to the release of histamine and other pro-inflammatory mediators after exposure to cold. The treatment of choice is nonsedating antihistamines, dosages of which may be increased up to fourfold if standard doses are ineffective. Here, we assess the effects of a standard 20 mg dose and up-dosing to 40 and 80 mg of bilastine in reducing the symptoms of CCU and inflammatory mediator release following cold challenge.

Methods

Twenty patients with CCU were included in this randomized, crossover, double-blind, placebo-controlled 12-week study. They received placebo, 20, 40 or 80 mg of bilastine daily each for 7 days with 14-day washout periods. The primary readout was change in critical temperature thresholds (CTT). Secondary readouts were changes in pruritus, levels of histamine IL-6, IL-8 and TNF-α collected by skin microdialysis and safety and tolerability of bilastine.

Results

Bilastine 20 mg was highly effective (P < 0.0001) in reducing CTT. Up-dosing to 80 mg significantly (P < 0.04) increased its effectiveness. At this dose, 19 of 20 (95%) patients responded to treatment, with 12 of 20 (60%) becoming symptom free. Only one patient was refractory to treatment. Microdialysis levels of histamine, IL-6 and IL-8 assessed 1–3 h after cold challenge were significantly (P < 0.05) decreased following up-dosing with 80 mg bilastine. Bilastine treat-ment was well tolerated without evidence of increased sedation with dose escala-tion.

Conclusions

Bilastine was effective in reducing the symptoms of patients with CCU. Increased efficacy of bilastine with fourfold up-dosing was without sedation and supports urticaria treatment guidelines.

Rupatadine improves quality of life in mastocytosis: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Mastocytosis is frequently associated with mast cell-mediated symptoms which require relieving medication. While second generation antihistamines (sgAHs) are the first line therapeutic strategy to treat mast cell mediator-related symptoms, controlled clinical trials on how they improve quality of life have not been performed.

METHODS

This randomized, double-blind, placebo-controlled, cross-over trial assessed rupatadine 20 mg daily in the treatment of mastocytosis symptoms in 30 adult patients. Symptoms were assessed by a visual analogue scale (VAS) and symptom specific quality of life questionnaire (ItchyQoL).

RESULTS

The mean ItchyQoL total score and VAS symptom score were significantly improved in the rupatadine treatment phase compared with placebo. There were also significant reductions from placebo in the severity of itch, wheal and flare, flushing, tachycardia and headache but not gastrointestinal symptoms.

CONCLUSIONS

In this first comprehensive trial of a sgAH in mastocytosis, rupatadine 20 mg daily for 4 weeks significantly controlled symptoms and improved patients' quality of life.

H(1)-antihistamines and urticaria: how can we predict the best drug for our patient?

Urticaria, and especially chronic spontaneous urticaria (CSU), is a difficult condition to treat. Consequently, clinicians need to use the best H(1)-antihistamines currently available and the pharmaceutical industries need to keep developing H(1)-antihistamines that are more effective than the ones we have today. To do this we need to be able to compare the clinical efficacy of both established and new drugs. Obviously, the ideal way to do this is to use head-to-head studies in CSU. However, such studies are extremely expensive and, in the case of novel molecules, have ethical and logistical problems. Consequently, we need to have predictive models. Although determination of Ki, an indicator of the in vitro potency of an H(1)-antihistamine, may help in the initial selection of candidate molecules, the large differences in volume of distribution and tissue accumulation in humans, precludes this from being a good predictor of clinical efficacy in CSU. From the data reviewed in this article, especially the direct comparative data of desloratadine and levocetirizine in weal and flare studies and CSU, weal and flare response would appear to be the best indicator we have of effectiveness of H(1)-antihistamines in clinical practice. However, it must be pointed out that the conclusion is, essentially, based on detailed comparisons of two drugs in studies sponsored by pharmaceutical companies. Consequently, to confirm the conclusions of this review, a multicentre study independent from the influence of pharmaceutical companies should be commissioned to compare the speed of onset and effectiveness of desloratadine, fexofenadine and levocetirizine in chronic spontaneous urticaria and against histamine-induced weal and flare responses in the same patients so that we have a clear understanding of the predictive value of our models.

Platelet-activating factor (PAF) induces wheal and flare skin reactions independent of mast cell degranulation

BACKGROUND

Platelet-activating factor (PAF) causes wheal and flare responses which are abrogated by H1-antihistamines giving rise to the hypothesis that PAF-induced wheal development is secondary to histamine release from dermal mast cells. But is this hypothesis correct?

METHODS

Wheal and flare responses were induced by intradermal injection of PAF, codeine and histamine in 14 healthy volunteers. Dermal histamine and PGD2 contractions were measured using microdialysis.

RESULTS

PAF, unlike histamine and codeine, did not cause a statistically significant rise in mean histamine levels with ten persons showing negligible histamine release. Codeine caused a significant but variable histamine release, ranging from 29 to 282 ng/ml. Codeine, but not PAF or histamine, caused a small but statistically significant release of PGD2.

CONCLUSION

Wheal and flare reactions in human skin induced by PAF are not associated with histamine release and, therefore, appear to be independent of mast cell degranulation.

RhinAsthma patient perspective: a short daily asthma and rhinitis QoL assessment

BACKGROUND

The present study aimed to develop a short validated patient-completed questionnaire, the RhinAsthma Patient Perspective (RAPP), to assess the health-related quality of life (HRQoL) in patients with asthma and comorbid allergic rhinitis in clinical practice.

METHODS

A provisional RAPP questionnaire was formed from candidate items identified through retrospective analysis of 333 RHINASTHMA questionnaires. This was then tested on 150 asthma patients with allergic rhinitis.

RESULTS

Psychometric analyses identified eight items fitting a unidimensional model to form RAPP. Internal consistency (Cronbach's alpha coefficient > 0.8) and agreement with RHINASTHMA (r = -0.31, P = 0.0001) were excellent. Criterion, discriminant, and convergent validity were good. Reliability in 47 stable patients was very good (intra-class and concordance correlation coefficients were 0.90 and 0.89, respectively). Responsiveness in 103 patients with health improvement or deterioration was significantly associated with changes in Global Rating Scale (r = -0.4965, P < 0.01), Rhinitis Visual Analogue Scale (r = 0.5722, P < 0.01) and asthma control test (r = -0.6483, P < 0.01). Minimal clinical difference in the analyzed population was 2.

CONCLUSION

RhinAsthma Patient Perspective is a simple eight-question questionnaire with good measurement properties and sensitivity to health changes, which will provide a valid, reliable and standardized HRQoL measurement in patients with asthma and comorbid allergic rhinitis in clinical practice.

Critical temperature threshold measurement for cold urticaria: a randomized controlled trial of H(1) -antihistamine dose escalation

BACKGROUND

Cold urticaria is a rare but severe and potentially lethal condition. It is primarily treated symptomatically with H(1) -antihistamines. However, patients have a variable response to these drugs and, to date, it has not been possible to predict readily the response to therapy of individual patients.

OBJECTIVES

To assess the severity of the cold urticaria in naive patients and the response to therapy of patients treated with increasing doses of an H(1) -antihistamine by measurement of critical temperature thresholds (CTT) for producing weals on the forearm.

METHODS

This was a two-centre, hospital-based, double-blind, randomized, parallel-group study of patients with a confirmed diagnosis of cold urticaria of at least 6 months' duration. Patient groups received either a constant dose of desloratadine 5 mg daily for 6 weeks (n = 13), or escalating doses of desloratadine: 5 mg daily for the first 2 weeks, 10 mg daily for the second 2 weeks and 20 mg daily for the final 2 weeks (n = 15). Only one adverse event that appeared to be drug related was reported: mild fatigue after treatment with desloratadine 10 mg that lasted for about 3 weeks and resolved at the end of the study.

RESULTS

The desloratadine 5 mg daily dose produced a submaximal reduction of mean CTT which remained relatively constant over 6 weeks. Dose escalation increased efficacy, the reduction in mean CTT at four-times the standard daily dose being significantly greater (P = 0·03) than with the standard dose. Individually, no patient became symptom free (CTT < 4 °C) on 5 mg, while two became symptom free on 10 mg and a further three on 20 mg desloratadine daily.

CONCLUSIONS

Measurement of CTT allows for individualized risk management and therapy in patients with cold urticaria.

An internet survey on self-reported food allergy in Greece: clinical aspects and lack of appropriate medical consultation

BACKGROUND

Food allergy (FA) represents a common and worldwide disorder but in publications referring to FA the reported diagnosis is rarely confirmed. Consequently, the subjectively assessed FA may negatively affect the quality of life of patients and their families.

OBJECTIVE

We have conducted this internet survey in order to estimate the self-reported perception of FA in Greece.

METHODS

A standard anonymous questionnaire was posted for a 3-month period on http://www.in.gr, a Greek popular Internet portal. Each individual could participate only once. Participants were screened for the presence or history of FA by a key question and were then asked to provide information on symptoms, course and management.

RESULTS

A total of 3673 adult subjects (mean age 34.2 years, range 18-74, females 61.3%), reporting FA were included in analysis. Most reported reactions were related to fruits (14.9%), seafood (10.7%) and nuts (9.2%). The first episode occurred principally during the second (29.2%) and third (30.9%) decade within 3 h from consumption (82.2%). Predominant symptoms were urticaria and oral allergy syndrome (almost 25% each one). Nearly half of the participants sought no medical advice, while 31.4% asked for an allergist's consultation. Almost 21% of reactors were hospitalized; nuts, severity of symptoms (lower respiratory and/or cardiovascular), onset in lower age, previous exercise and concomitant alcohol and/or aspirin intake were positively associated with hospitalization.

CONCLUSION

Although FA causes severe anaphylactic episodes, almost 50% of individuals who experience symptoms perceived as FA do not seek medical advice. Awareness programmes must be carried out in order to increase consciousness about this potentially fatal medical condition.

Unmet clinical needs in chronic spontaneous urticaria. A GA²LEN task force report

Chronic spontaneous urticaria, formerly also known as chronic idiopathic urticaria and chronic urticaria (CU), is more common than previously thought. At any time, 0.5-1% of the population suffers from the disease (point prevalence). Although all age groups can be affected, the peak incidence is seen between 20 and 40 years of age. The duration of the disease is generally 1-5 years but is likely to be longer in more severe cases, cases with concurrent angioedema, in combination with physical urticaria or with a positive autologous serum skin test (autoreactivity). Chronic spontaneous urticaria has major detrimental effects on quality of life, with sleep deprivation and psychiatric comorbidity being frequent. It also has a large impact on society in terms of direct and indirect health care costs as well as reduced performance at work and in private life. In the majority of patients, an underlying cause cannot be identified making a causal and/or curative treatment difficult. Nonsedating H₁-antihistamines are the mainstay of symptomatic therapy, but treatment with licensed doses relieves symptoms effectively in < 50% of patients. Although guideline-recommended updosing up to fourfold increases symptom control in many patients, a substantial number of patients have only little benefit from H₁ -antihistamines. Consequently, there is a great need for new therapeutic strategies.

Risk of first-generation H(1)-antihistamines: a GA(2)LEN position paper

BACKGROUND

First-generation H(1)-antihistamines obtained without prescription are the most frequent form of self-medication for allergic diseases, coughs and colds and insomnia even though they have potentially dangerous unwanted effects which are not recognized by the general public.

AIMS

To increase consumer protection by bringing to the attention of regulatory authorities, physicians and the general public the potential dangers of the indiscriminate use first-generation H(1)-antihistamines purchased over-the counter in the absence of appropriate medical supervision.

METHODS

A GA(2)LEN (Global Allergy and Asthma European Network) task force assessed the unwanted side-effects and potential dangers of first-generation H1-antihistamines by reviewing the literature (Medline and Embase) and performing a media audit of US coverage from 1996 to 2008 of accidents and fatal adverse events in which these drugs were implicated.

RESULTS

First-generation H(1)-antihistamines, all of which are sedating, are generally regarded as safe by laypersons and healthcare professionals because of their long-standing use. However, they reduce rapid eye movement (REM)-sleep, impair learning and reduce work efficiency. They are implicated in civil aviation, motor vehicle and boating accidents, deaths as a result of accidental or intentional overdosing in infants and young children and suicide in teenagers and adults. Some exhibit cardiotoxicity in overdose.

CONCLUSIONS

This review raises the issue of better consumer protection by recommending that older first-generation H(1)-antihistamines should no longer be available over-the-counter as prescription- free drugs for self-medication of allergic and other diseases now that newer second- generation nonsedating H(1)-antihistamines with superior risk/benefit ratios are widely available at competitive prices.

EAACI/GA(2)LEN/EDF/WAO guideline: definition, classification and diagnosis of urticaria

This guideline, together with its sister guideline on the management of urticaria [Zuberbier T, Asero R, Bindslev-Jensen C, Canonica GW, Church MK, Giménez-Arnau AM et al. EAACI/GA(2)LEN/EDF/WAO Guideline: Management of urticaria. Allergy, 2009; 64:1427-1443] is the result of a consensus reached during a panel discussion at the 3rd International Consensus Meeting on Urticaria, Urticaria 2008, a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the EU-funded network of excellence, the Global Allergy and Asthma European Network (GA(2)LEN), the European Dermatology Forum (EDF) and the World Allergy Organization (WAO). Urticaria is a frequent disease. The life-time prevalence for any subtype of urticaria is approximately 20%. Chronic spontaneous urticaria and other chronic forms of urticaria do not only cause a decrease in quality of life, but also affect performance at work and school and, as such, are members of the group of severe allergic diseases. This guideline covers the definition and classification of urticaria, taking into account the recent progress in identifying its causes, eliciting factors, and pathomechanisms. In addition, it outlines evidence-based diagnostic approaches for different subtypes of urticaria. The correct management of urticaria, which is of paramount importance for patients, is very complex and is consequently covered in a separate guideline developed during the same consensus meeting. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS).

EAACI/GA(2)LEN/EDF/WAO guideline: management of urticaria

This guideline, together with its sister guideline on the classification of urticaria (Zuberbier T, Asero R, Bindslev-Jensen C, Canonica GW, Church MK, Giménez-Arnau AM et al. EAACI/GA(2)LEN/EDF/WAO Guideline: definition, classification and diagnosis of urticaria. Allergy 2009;64: 1417-1426), is the result of a consensus reached during a panel discussion at the Third International Consensus Meeting on Urticaria, Urticaria 2008, a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the EU-funded network of excellence, the Global Allergy and Asthma European Network (GA(2)LEN), the European Dermatology Forum (EDF) and the World Allergy Organization (WAO). As members of the panel, the authors had prepared their suggestions regarding management of urticaria before the meeting. The draft of the guideline took into account all available evidence in the literature (including Medline and Embase searches and hand searches of abstracts at international allergy congresses in 2004-2008) and was based on the existing consensus reports of the first and the second symposia in 2000 and 2004. These suggestions were then discussed in detail among the panel members and with the over 200 international specialists of the meeting to achieve a consensus using a simple voting system where appropriate. Urticaria has a profound impact on the quality of life and effective treatment is, therefore, required. The recommended first line treatment is new generation, nonsedating H(1)-antihistamines. If standard dosing is not effective, increasing the dosage up to four-fold is recommended. For patients who do not respond to a four-fold increase in dosage of nonsedating H(1)-antihistamines, it is recommended that second-line therapies should be added to the antihistamine treatment. In the choice of second-line treatment, both their costs and risk/benefit profiles are most important to consider. Corticosteroids are not recommended for long-term treatment due to their unavoidable severe adverse effects. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS).

Treating allergic rhinitis: continuous versus on-demand regime? Executive summary of the Supportive Initiatives for the Global Management of Allergy (SIGMA): report from the Belgian Working Group

This Supportive Initiative for the Global Management of Allergy (SIGMA) initiative gathered together four multidisciplinary and inter-university groups of Belgian experts in the treatment of allergic rhinitis to review the literature and come to a consensus opinion on the global management of allergy. Their conclusions were as follows. Group 1 concluded that in children suffering from allergic rhinitis, there is sufficient expert opinion in favour of continuous treatment with both H1-antihistamines and corticosteroids for controlling symptoms during periods of allergen exposure, but not to support continuous treatment during periods when symptoms are negligible in an attempt to prevent the development of new allergic diseases. Group 2 came to similar conclusions in adults. Group 3 considered adults with concomitant asthma and stressed the crucial necessity to screen each asthmatic for allergic rhinitis and institute appropriate therapy for both conditions. Even though efficacious treatment algorithms are available for both rhinitis and asthma, an integrated management of these frequently concomitant diseases is not always prescribed even though there is a proven clinical advantage of adequate treatment of the nose of asthmatics. Group 4 concluded that for both H1-antihistamines and nasal corticosteroids, safety data indicate that continuous treatment may be given without fears of adverse consequences. With regard to the cost implications of continuous therapy versus on-demand therapy, there are indications that effective treatment of allergic rhinitis by continuous treatment reduces overall drug costs, particularly that of escape medication and indirect costs in the form of days absent from work and school.

A comparison of levocetirizine and desloratadine in the histamine-induced wheal and flare response in human skin in vivo

BACKGROUND

The histamine-induced wheal and flare response was used to compare quantitatively the antihistaminic potency of levocetirizine and desloratadine.

METHODS

In this double-blind, placebo-controlled crossover study, 24 healthy male non-atopic volunteers received weekly single doses of 1.25, 2.5 or 5 mg levocetirizine, 2.5, 5 or 10 mg desloratadine, or placebo. Four hours after dosing, histamine (100 mg/ml) skin prick tests were performed on the volar surface of both forearms. The diameters of the wheals and flares were measured 10 minutes later. Sedation was evaluated using a visual analogue scale and a motricity test. The effects of individual drug doses were compared using Student's t-test for paired data and the overall effects of the two drugs by ANOVA.

RESULTS

All doses of levocetirizine significantly (P < 0.0001) inhibited both wheals and flares in a dose-related manner. Only the 10 mg dose of desloratadine achieved significant inhibition of response. ANOVA showed levocetirizine to be significantly (P < 0.0001) more active than desloratadine. Neither drug caused significant sedation or loss of motricity.

CONCLUSION

Levocetirizine is significantly more effective than desloratadine in inhibiting wheal and flare responses to histamine in human skin in vivo, with 1.25 mg levocetirizine being more effective than 10 mg desloratadine.

Reduced structural proteins in the conjunctival epithelium in allergic eye disease

AIMS

Allergic eye disease affects up to 20% of the population with varying severity. The conjunctival epithelium plays a key role in allergic eye disease. The purpose of this study was to determine whether the conjunctival epithelium is abnormal in allergic eye disease.

METHODS

Conjunctival biopsy samples were taken from patients with seasonal allergic conjunctivitis (SAC) 'in' and 'out of season' and nonatopic control subjects. Specimens were fixed in glycol methacrylate, 2 microm serial sections cut and Image-J used to assess the sites and areas of immuno-staining.

RESULTS

E-cadherin, CD44, keratins K5/6, K8, K13, K14, K18 and pan-keratin immuno-staining were all significantly lower in patients 'out of season' compared with normal controls. No structural differences in the epithelium were observed between the two groups. The epithelium of patients 'in season' was thicker and immuno-staining of the above markers similar to controls.

CONCLUSIONS

The expression of a wide spectrum of epithelial cell adhesion proteins and cytoskeletal elements is downregulated in the conjunctiva of SAC patients 'out of season' compared with normal controls. We suggest that this could have an important impact on the ability of the epithelium to protect itself against allergen penetration, potentially influencing the development and course of allergic eye disease and offering a novel area for therapeutic control.

Allergen activates peripheral blood eosinophil nuclear factor-kappaB to generate granulocyte macrophage-colony stimulating factor, tumour necrosis factor-alpha and interleukin-8

BACKGROUND

Allergic inflammation is characterized by the influx and activation of eosinophils. Cytokines generated by both resident and infiltrating cells are responsible for the initiation and maintenance of this pathogenesis. This study focuses on allergen-induced activation of eosinophil NF-kappaB and generation of granulocyte macrophage-colony stimulating factor (GM-CSF), TNF-alpha, and IL-8.

METHODS

Peripheral blood eosinophils were enriched to >99.9% by Percoll gradient sedimentation and negative magnetic affinity chromatography. NF-kappaB activation by 10 microg/mL house dust mite (HDM) extract was demonstrated immunocytochemically using a monoclonal antibody against the active form of NF-kappaB (NF-kappaBa). The authenticity of NF-kappaB was confirmed by Western blot. Cytokine production was assessed both by immuno-staining of eosinophils and by assay of cytokines in the cell supernatant.

RESULTS

Activation of peripheral blood eosinophils from atopic, but not non-atopic, donors induced activation of NF-kappaB, which peaked at 4 h and was accompanied by a decline in IkappaB-alpha. The activation of authentic NF-kappaB was confirmed in gel shift assays. Supershift assays showed p65 to be the major subunit of eosinophil NF-kappaB. Immunofluorescent confocal microscopy demonstrated localization of NF-kappaBa to the nucleus. Following activation, cytokine immunoreactivity was seen in a fraction of the eosinophils and cytokines were released into the supernatant. The NF-kappaB inhibitors, calpain inhibitor 1 (10 microm), pentoxifylline (0.5 mm), pyrrolidine dithiocarbamate (PDTC, 10 microm) or gliotoxin (1 pg/mL) reduced the generation of GM-CSF, TNF-alpha and IL-8 in parallel with their inhibition of NF-kappaB.

CONCLUSIONS

HDM allergen activates human eosinophil NF-kappaB leading to the production of the cytokines GM-CSF, TNF-alpha and IL-8. We speculate that a role for eosinophil NF-kappaB-dependent cytokines is to act as an autocrine loop augmenting the survival of eosinophils in vivo.

Investigation into the mechanisms by which nedocromil sodium, frusemide and bumetanide inhibit the histamine-induced itch and flare response in human skin in vivo

BACKGROUND

In a previous study, iontophoresis of nedocromil sodium into human skin in vivo was shown to reduce histamine-induced itch and flare. In asthma, the Na+/K+/2Cl- cotransporter inhibitors, frusemide and bumetanide, have been reported to have many similar actions to nedocromil sodium.

OBJECTIVE

To compare the effects of these drugs in the histamine-induced itch, flare and weal response in human skin in vivo and elucidate their site of action.

METHODS

Nedocromil sodium, frusemide bumetanide and reversed osmosis water (control), were introduced by iontophoresis into the forearm skin of 10 volunteers in each of two single-blind studies. In study 1, histamine (20 microL of 100 microM) or vehicle was injected into the area of iontophoresis 10 min later. In study 2, histamine or vehicle was injected 5 mm outside the area of iontophoresis so the flare developed over the area of iontophoresis. Itch was scored on a visual analogue scale every 20 s for 5 min, flare areas were assessed using scanning laser Doppler imaging up to 10 min and weal was assessed by planimetry at 10 min.

RESULTS

In study 1, nedocromil sodium, frusemide and bumetanide reduced itch scores by 36%, 48% and 34%, respectively, and flare areas by 17%, 26% and 15% respectively (all P<0.05). Weal areas and blood flux in the flare were unaffected. In study 2, itch scores, flare areas and weal areas were not inhibited. Also, blood flux values in areas of drug and water iontophoresis were not different.

CONCLUSION

This study has provided evidence to support the hypothesis that nedocromil sodium, frusemide and bumetanide inhibit sensory nerve activation to reduce the itch and flare responses induced by histamine in human skin in vivo. It is likely that inhibition of a Na+/K+/2Cl- cotransporter in the sensory nerve membrane is a possible mechanism of action.

Comparison of the effects of desloratadine and levocetirizine on histamine-induced wheal, flare and itch in human skin

OBJECTIVE

A previous study showed the inhibitory effects of loratadine on histamine-induced wheal, flare and itch in human skin to be very variable between individuals. It was hypothesised that this variability may have been due to differences in the rates of metabolism of loratadine to its active form, desloratadine. This double blind, crossover study examined the effects of desloratadine in 12 healthy volunteers. Levocetirizine was used as a comparator.

METHODS

Desloratadine (5 mg), levocetirizine (5 mg) or placebo was taken orally 4 h before an intradermal injection of histamine (20 microL, 100 microM) or vehicle control into the forearm skin. Flare areas were assessed by scanning laser Doppler imaging before and at 30 s intervals for a period of 9 min. Wheal areas were measured by planimetry at 10 min. Itch was scored every 30 s for 5 min using a visual analogue scale.

RESULTS

Following placebo administration, the mean (+/- SEM) wheal area at 10 min was 79.3 +/- 6.9 mm(2), mean flare area for the first 5 min following challenge 26.6 +/- 2.7 cm(2), and itch score for the same period 48.5 +/- 7.6%. The effects of desloratadine were variable between individuals, mean reductions in the wheal and flare areas being 17% (P = 0.033) and 12% (P = 0.036). Desloratadine did not reduce itch significantly. Levocetirizine was more consistent in its effects, mean reductions in wheal, flare and itch being 51%, 67% 78% respectively (all P < 0.001).

CONCLUSIONS

A single dose of 5 mg levocetirizine produced more consistent and greater inhibitory effects on histamine-induced wheal, flare and itch than did 5 mg desloratadine. The difference is suggested to reflect the basic pharmacokinetics of the two drugs.

Effects of blood flow on the in vivo recovery of a small diffusible molecule by microdialysis in human skin

The aim of this study was to investigate the impact of changes in local blood flow on the recovery of a small, diffusible molecule (sodium fluorescein) from the extravascular tissue space of the skin, by microdialysis in vivo. Loss and recovery of fluorescein by linear microdialysis probes (5-kDa molecular mass cutoff, 0.2 mm diameter) inserted 1 mm apart in pairs, at three sites in the skin of the volar surface of the forearm of healthy volunteers, was measured under conditions of basal, reduced (noradrenaline, 0.005 mg/ml), and increased (glyceryl trinitrate, patch) blood flow. Whereas loss of tracer from the delivery probe appeared unaffected by changes in local blood flow, retrieval of fluorescein by the second probe was directly related to blood flux, measured using scanning laser Doppler imaging. Steady-state recovery at vasoconstricted sites was 4.0 +/- 0.7 microg. ml(-1) compared with 1.8 +/- 0.7 microg. ml(-1) at control sites (p < 0.001). Local vasodilatation reduced the retrieval of fluorescein by approximately 50% to give a steady-state concentration of fluorescein in the dialysate at 40 to 50 min after the start of perfusion of 0.9 +/- 0.3 microg. ml(-1) (p = 0.05). These studies in the skin are consistent with microdialysis theory. They suggest that clearance of solute by the blood will have a significant impact on microdialysis probe recovery and that, in the skin, the magnitude of this clearance is directly related to blood flow.

Are cysteinyl leukotrienes involved in allergic responses in human skin?

BACKGROUND

Cysteinyl leukotrienes have been suggested to be involved in producing the symptoms of both the early and late phases of the allergic response in the lung and other tissues.

OBJECTIVE

To use scanning laser Doppler imaging, microdialysis and immunocytochemistry to explore the mediator and cellular mechanisms of the dermal allergic response.

METHODS

Thirteen atopic volunteers received intradermal injections into the forearm of grass pollen or D. pteronyssinus extract. Changes in dermal blood flow up to 8 h were monitored by scanning laser Doppler imaging. The release of histamine, PGD2 and LTC4/D4/E4 was assessed by dermal microdialysis. Skin biopsies were taken at 6 h to determine numbers of mast cells, eosinophils, basophils, Langerhans' cells, and monocytes/macrophages, and the expression of COX-1, COX-2, 5-LO and FLAP.

RESULTS

Allergen provocation produced an immediate weal and flare response followed by an erythematous induration peaking at 6 h. During the first hour, c. 84 pmoles of histamine and c. 0.3 pmoles of PGD2 were recovered by microdialysis (both P < 0.001) but LTC4/D4/E4 was undetectable. No histamine, PGD2 or LTC4/D4/E4 was detectable at later times. Immunocytochemical examination of biopsies taken at 8 h showed increased numbers of eosinophils and basophils and in COX-2, 5-LO and FLAP, but not COX-1. Expression of 5-LO and FLAP was associated primarily with eosinophils.

CONCLUSIONS

These findings suggest that inflammatory cells recruited to the site of allergen injection are not activated to release detectable amounts of cysteinyl leukotrienes. Hence, it is unlikely that the late-phase erythematous induration is mediated by this autocoid.

H1-antihistamines: inverse agonism, anti-inflammatory actions and cardiac effects

This review addresses novel concepts of histamine H1-receptor function and attempts to relate them to the anti-inflammatory effects of H1-antihistamines. Furthermore, the molecular mechanisms underlying the cardiotoxic effects of H1-antihistamines are discussed. H1-receptors are G-protein-coupled-receptors (GPCRs), the inactive and active conformations of which coexist in equilibrium. The degree receptor activation in the absence of histamine is its 'constitutive activity'. In this two-state model, histamine acts as an agonist by combining with and stabilizing the activated conformation of the H1-receptor to shift the equilibrium towards the activated state. Drugs classified previously as antagonists act as either inverse agonists or neutral antagonists. Inverse agonists combine with and stabilize the inactive conformation of the receptor to shift the equilibrium towards the inactive state. Thus, they may down-regulate constitutive receptor activity, even in the absence of histamine. Neutral antagonists combine equally with both conformations of the receptor, do not affect basal receptor activity but do interfere with agonist binding. All H1-antihistamines examined to date are inverse agonists. As the term 'H1-receptor antagonists' is obviously erroneous, we suggest that it be replaced by 'H1-antihistamines'. The observations that H1-receptors modulate NF-kappaB activation and that there are complex interactions between GPCRs, has allowed us to postulate receptor dependent-mechanisms for some anti-inflammatory effects of H1-antihistamines, e.g. inhibition of ICAM-1 expression and the effects of bradykinin. Finally, the finding that blockade of HERG1 K+ channels is the mechanism by which some H1-antihistamines may cause cardiac arrhythmias has allowed the development of preclinical tests to predict such activity.

Comparison of the effects of levocetirizine and loratadine on histamine-induced wheal, flare, and itch in human skin

BACKGROUND

This randomized, double-blind, crossover study compared the effects of the R-enantiomer of cetirizine, levocetirizine, with those of loratadine on the wheal, flare, and itch response to histamine in human skin.

METHODS

Levocetirizine (5 mg), loratadine (10 mg), or placebo was taken orally 4 h before the intradermal injection of histamine (20 microl, 100 microM) or the control vehicle into the forearm skin of healthy volunteers. Flare areas were assessed by scanning laser Doppler imaging before and at 30-s intervals for a period of 9 min. Wheal areas were measured by planimetry at 10 min. Itch was scored every 30 s with a visual analogue scale.

RESULTS

After placebo administration, the mean peak flare area was 23.01+/-1.94 cm(2), the wheal area 248+/-27 mm(2), and the cumulative itch score 28.8+/-4.6% (mean+/-SEM). Levocetirizine reduced the flare, wheal, and itch by 60%, 68%, and 91%, respectively (all P<0.001, Student's t-test for paired data). The effects of loratadine were variable and not statistically significant.

CONCLUSION

Levocetirizine (5 mg) is a potent inhibitor of the effects of histamine in human skin with an efficacy that exceeded that of loratadine (10 mg) when single doses of the drugs were administered 4 h before the test.