Chronic urticaria and coagulation: pathophysiological and clinical aspects

Exploring the Bidirectional Effects of Gut Microbiota and Short-Chain Fatty Acids on Urticaria Subtypes Through Mendelian Randomization and Mediation Analysis

Background

Emerging evidence links gut microbiota and their by-products, notably short-chain fatty acids (SCFAs), to urticaria. This study employs multiple Mendelian Randomization (MR) analyses to unravel the complex interactions among gut microbiota, SCFAs, and different subtypes of urticaria, aiming to elucidate the underlying mechanisms and enhance future clinical research.

Methods

We analyzed published genome-wide association study (GWAS) summary statistics to identify associations between gut microbiota and three common subtypes of urticaria: spontaneous, dermatographic, and temperature-triggered. Initial two-sample and reverse MR analyses explored the causality in these relationships. Subsequent multivariate MR analyses investigated the role of SCFAs in modulating these interactions, with multiple sensitivity analyses to ensure robustness.

Findings

Specific taxa were differently associated with various urticaria subtypes. From microbiota to urticaria: one taxon was negatively associated with dermatographic urticaria; seven taxa were negatively associated and four positively associated with temperature-triggered urticaria; four taxa were negatively associated and six positively associated with spontaneous urticaria. Conversely, from urticaria to microbiota: five taxa were negatively associated with dermatographic urticaria; four were negatively and two positively associated with temperature-triggered urticaria; and two were negatively associated with spontaneous urticaria. These associations were observed at a nominal significance level (P < 0.05). After applying Bonferroni correction for multiple testing, these associations did not reach statistical significance. The observed trends, however, provide insights into potential microbiota-urticaria interactions. Multivariate MR analyses elucidated the role of SCFAs, particularly acetate, which plays a crucial role in modulating immune response. Adjusting for acetate revealed direct effects of Actinobacteria, Bifidobacteriales, and Bifidobacteriaceae on spontaneous urticaria, with corresponding mediation effects of -22%, -24.9%, and -24.9% respectively. Similarly, adjustments for Alcaligenaceae and Betaproteobacteria indicated significant negative effects of acetate on dermatographic and spontaneous urticaria, with mediation effects of -21.7% and -23.7%, respectively.

Conclusion

This study confirms the interconnected roles of gut microbiota, SCFAs, and urticaria. It highlights SCFAs' potential mediating role in influencing urticaria through microbiota, providing insights for future therapeutic strategies.

Combining dipyridamole and cilostazol with up-dosing antihistamines improves outcomes in chronic spontaneous urticaria with high D-dimer levels: A randomized controlled trial

In a double-blind, randomized controlled trial, we investigated the effectiveness of adding antiplatelet drugs to up-dosing antihistamines for the treatment of chronic spontaneous urticaria (CSU) in patients with elevated D-dimer levels who had an inadequate response to conventional antihistamine doses. Twenty patients with Urticaria Activity Score over 7 days (UAS7) ≥16 and D-dimer >500 ng/mL were randomized to receive either antiplatelet therapy (cilostazol 150 mg/day + dipyridamole 50 mg/day) with antihistamine (desloratadine 20 mg/day) or antihistamine alone for 4 weeks. The antiplatelet group demonstrated a greater decrease in UAS7 compared to the control group (28.10 to 8.90 vs. 22.90 to 16.40, p < 0.001 vs. p = 0.054). Both groups experienced improved quality of life (DLQI), but the improvement was greater in the antiplatelet group (p = 0.046). D-dimer levels decreased only in the antiplatelet group (1133.67 ng/mL to 581.89 ng/mL, p = 0.013) with no significant change observed in the control group. This suggests that combining dipyridamole and cilostazol with up-dosing antihistamines may be more effective for CSU patients with high D-dimer levels compared to up-dosing antihistamines alone. This could be due to a reduction in platelet activation, as evidenced by the decrease in D-dimer levels observed in the antiplatelet group.

Intersecting pathways: evaluating inflammatory markers and metabolism in chronic spontaneous urticaria with a multi-marker approach

BACKGROUND

Chronic spontaneous urticaria (CSU) is an inflammatory skin disease with intricate mechanisms. This study comprehensively assessed markers from diverse metabolic pathways, including novel inflammatory indicators, to evaluate their potential for diagnosing and monitoring CSU.

MATERIALS AND METHODS

In the study involving 90 CSU patients and 90 healthy controls, the levels of albumin, high-density lipoprotein (HDL), fibrinogen, uric acid, D-dimer, C-reactive protein (CRP), and white blood cells (WBC) values were analyzed. The D-dimer/albumin ratio (DAR), fibrinogen/albumin ratio (FAR), and uric acid/HDL ratio (UHR), considered novel inflammatory markers, were calculated. The Urticaria Activity Score 7 (UAS7) was also calculated. Pearson chi-squared test, Mann-Whitney U test, Spearman correlation coefficient, and univariate logistic regression analysis were employed for data analysis.

RESULTS

In the patient group, significant elevations were observed in DAR, FAR, fibrinogen, CRP, D-dimer, and UHR values. Additionally, albumin, HDL, and uric acid values exhibited significant decreases. HDL and albumin provided the most accurate results in the univariate logistic regression analysis. CRP had less accuracy, FAR exhibited greater accuracy than fibrinogen, and DAR demonstrated higher accuracy than D-dimer. There was no statistically significant correlation between the UAS7 and parameters. The considerable correlation of CRP with other parameters, except D-dimer, was also remarkable.

CONCLUSIONS

Indicators from diverse metabolic pathways, including albumin, HDL, uric acid, fibrinogen, D-dimer, and CRP, can be valuable in assessing CSU. In particular, FAR and DAR are emerging as potential markers to consider in the assessment of CSU.

Immunopathogenesis of urticaria: a clinical perspective on histamine and cytokine involvement

BACKGROUND

Urticaria is a clinical condition characterized by the appearance of wheals (hives), angioedema, or both. Over the last several decades, a better understanding of the mechanisms at play in the immunopathogenesis of urticaria has underscored the existence of numerous urticaria subtypes. Separating the different kinds of urticaria explicitly helps find the best detection method for the management of this skin disorder. Subtypes of urticaria also include both spontaneous and physical types. The conventional ones include spontaneous urticaria, constituting both acute and chronic urticaria. Therefore, a broad and effective therapy is essential for the diagnosis and treatment of urticaria.

METHODS

To understand the immunopathogenesis of urticaria, various databases, including PubMed, Scopus, and Web of Science, were used to retrieve original articles and reviews related to urticaria. While information on several clinical trials were obtained from clinicaltrials.gov database.

RESULTS

This article highlights the immunopathogenesis involved in the intricate interaction between cellular infiltration, immune reactions, coagulation cascades, and autoantibodies that underlie urticaria's pathophysiology.

CONCLUSION

The recent progress in understanding urticaria can help to understand the intricate characteristics in the immunopathogenesis of urticaria and could play a beneficial role in the management of urticaria.

Mast cell signaling and its role in urticaria

Chronic urticaria is a mast cell (MC)-driven disease characterized by the development of itching wheals and/or angioedema. In the last decades, outstanding progress has been made in defining the mechanisms involved in MC activation, and novel activating and inhibitory receptors expressed in MC surface were identified and characterized. Besides an IgE-mediated activation through high-affinity IgE receptor cross-linking, other activating receptors, including Mas-related G-protein-coupled receptor-X2, C5a receptor, and protease-activated receptors 1 and 2 are responsible for MC activation. This would partly explain the reason some subgroups of chronic spontaneous urticaria (CSU), the most frequent form of urticaria in the general population, do not respond to IgE target therapies, requiring other therapeutic approaches for improving the management of the disease. In this review, we shed some light on the current knowledge of the immunologic and nonimmunologic mechanisms regulating MC activation in CSU, considering the complex inflammatory scenario underlying CSU pathogenesis, and novel potential MC-targeted therapies, including surface receptors and cytoplasmic signaling proteins.

Time Course of Priming Effect of TF Inducers on Synergistic TF Expression and Intra-Cellular Gap Formation of Human Vascular Endothelial Cells via the Extrinsic Coagulation Cascade

Chronic spontaneous urticaria (CSU) is characterized by daily recurring wheal and flare with itch for more than 6 weeks. The extrinsic coagulation system has been shown to be activated in correlation with CSU severity. We have reported that tissue factor (TF), a trigger of the extrinsic coagulation cascade, is synergistically expressed on vascular endothelial cells by simultaneous stimulation with TF inducers (TFI), followed by activation of the extrinsic coagulation cascade and hyper permeability in vitro. However, vascular endothelial cells are not likely to be simultaneously stimulated by multiple TFIs under physiological conditions. Therefore, in order to know whether sequential, rather than simultaneous, stimuli with interval may induce synergistic activation of TF, we investigated the time course of the priming effects of each TFI for synergistic TF expression in vascular endothelial cells (HUVECs). We stimulated HUVECs with a TFI (first stimulation) and then stimulated cells with another TFI at indicated time points (second stimulation) and detected TF expression and activity. The TF expression induced by simultaneous stimulation diminished in a few hours. However, both synergistic enhancement of TF expression and activation level of the coagulation cascade were detected even when the second stimulation was added 18 or 22 h after the first stimulation. Thus, the priming effect of TFI for synergistic TF expression may persist for a half day or longer.

Biomarkers for Monitoring Treatment Response of Omalizumab in Patients with Chronic Urticaria

Chronic urticaria (CU) is a debilitating skin disease affecting around 1% of the population. CU can be subdivided into chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU). Different pathophysiological mechanisms have been proposed to play a role in the development of CU, and these are also being investigated as potential biomarkers in the diagnosis and management of the disease. As of now the only assessment tools available for treatment response are patient reported outcomes (PROs). Although these tools are both validated and widely used, they leave a desire for more objective measurements. A biomarker is a broad subcategory of observations that can be used as an accurate, reproducible, and objective indicator of clinically relevant outcomes. This could be normal biological or pathogenic processes, or a response to an intervention or exposure, e.g., treatment response. Herein we provide an overview of biomarkers for CU, with a focus on prognostic biomarkers for treatment response to omalizumab, thereby potentially aiding physicians in personalizing treatments.

Chronic spontaneous urticaria: a low-grade disseminated intravascular coagulation only partially reversed by Omalizumab

Chronic spontaneous urticaria (CSU) is a disorder characterized by wheals and/or angioedema. The coagulation cascade and inflammation pathways are closely linked together. The aim of our study was first to investigate the dynamics of clot formation in plasma (Clot Waveform Analysis, CWA) in a group of 47 patients with CSU along with other coagulative parameters dedicated to the study of hypercoagulability, such as D-Dimer, F 1 + 2 peptide, Fibrinogen, Platelet count and Mean Platelet Volume (MPV). Secondly, 23 out of 47 patients were treated with Omalizumab at four administration intervals from T0 to T4. A statistically significant increase in Activated Partial Thromboplastin (aPTT) ratio, D-Dimer, F1 + 2, Platelet count and MPV was found when compared with 53 healthy controls (HC). In contrast, the 2nd Derivative of aPTT showed lower values than those of the HC. No differences were found between 1st derivative of aPTT and Fibrinogen. D-Dimer only showed a significant difference between T0 and T3. An activation of both coagulation and fibrinolysis along with a weaker clot acceleration may be in agreement with a low-grade DIC. The accelerated turnover of platelets expressed by both an increase in platelet count and MPV further supports this pathway in CSU. Omalizumab does not affect the relationship between the immune and the hemostatic systems.

Combined microbiome and metabolome analysis of gut microbiota and metabolite interactions in chronic spontaneous urticaria

Background

The pathogenesis of chronic spontaneous urticaria (CSU) is unclear, and it turned out to be involved in biological processes, such as autoimmunity, autoallergy, inflammation, and coagulation. The gut microbiota plays an important role in immune and inflammatory diseases. However, the relationship between chronic spontaneous urticaria and the gut microbiota remains unknown.

Methods

The stool and serum samples were taken from 15 CSU patients and 15 normal controls. Changes in the composition of gut microbiota and serum metabolism in CSU patients and normal controls were analyzed by 16S ribosomal RNA (rRNA) gene sequencing and untargeted metabolomics.

Results

The results of 16S rRNA gene sequencing showed that compared with normal controls, CSU patients had increased α-diversity of gut microbiota and significant differences in β-diversity. At the phylum level, the relative abundance of Firmicutes increased and the relative abundance of Bacteroidetes and Proteobacteria decreased in CSU patients compared with healthy controls. At the genus level, six kinds of bacteria were significantly enriched in CSU patients and five in normal controls. Metabolomic analysis revealed altered levels of metabolites such as unsaturated fatty acids and purines. Correlation analysis of gut microbiota and metabolites showed that Lachnospira was negatively correlated with arachidonic acid, and Gemmiger was also negatively correlated with (±)8-HETE.

Conclusion

This study suggests that changes in gut microbiota and metabolites may play a role in immune and inflammatory pathways in the pathogenesis of CSU patients.

Biologics for chronic spontaneous urticaria: toward a personalized treatment

INTRODUCTION

Chronic spontaneous urticaria (CSU) is characterized by the recurrent occurrence of short-lived wheals with or without angioedema for more than 6 weeks. Although its pathogenesis is not completely defined, several mechanisms seem involved, including autoimmunity and autoallergy with complement and coagulation activation. Various biologics are currently available or under investigation to counteract different CSU pathomechanisms.

AREAS COVERED

The recent literature dealing with biologics in the treatment of CSU was screened and analyzed; the different treatments were divided into anti-IgE and other than anti-IgE biologics. The latter were subdivided according to their target mechanisms.

EXPERT OPINION

Biologic drugs exert their effects in a very precise and specific manner. A majority of patients (arguably those with type I disease) respond to anti-IgE treatment. Others, possibly with type IIa disease, show a slow response to anti-IgE drugs. Things are much more complicated in anti-IgE-refractory patients. Some respond well to nonspecific immune suppressors, such as corticosteroids and cyclosporin suggesting that an immune-mediated pathogenic mechanism, not involving the high-affinity IgE receptor, is probably active. Several ongoing studies are evaluating biologics and small molecules counteracting other pathomechanisms, including anti-receptor biologics, Bruton tyrosine kinase (BTK) inhibitors, mast cell targets, and specific cytokines.

Urticaria

Urticaria is an inflammatory skin disorder that affects up to 20% of the world population at some point during their life. It presents with wheals, angioedema or both due to activation and degranulation of skin mast cells and the release of histamine and other mediators. Most cases of urticaria are acute urticaria, which lasts ≤6 weeks and can be associated with infections or intake of drugs or foods. Chronic urticaria (CU) is either spontaneous or inducible, lasts >6 weeks and persists for >1 year in most patients. CU greatly affects patient quality of life, and is linked to psychiatric comorbidities and high healthcare costs. In contrast to chronic spontaneous urticaria (CSU), chronic inducible urticaria (CIndU) has definite and subtype-specific triggers that induce signs and symptoms. The pathogenesis of CSU consists of several interlinked events involving autoantibodies, complement and coagulation. The diagnosis of urticaria is clinical, but several tests can be performed to exclude differential diagnoses and identify underlying causes in CSU or triggers in CIndU. Current urticaria treatment aims at complete response, with a stepwise approach using second-generation H1 antihistamines, omalizumab and cyclosporine. Novel treatment approaches centre on targeting mediators, signalling pathways and receptors of mast cells and other immune cells. Further research should focus on defining disease endotypes and their biomarkers, identifying new treatment targets and developing improved therapies.

Annular urticarial lesions

Annular urticarial configurations are often associated with acute and chronic urticaria. Such lesions may be short-lived, migratory, transient, pruritic, and resolving with no residual evidence, making the diagnosis of urticaria an obvious one. Annular urticarial lesions can be the presenting signs of various cutaneous and systemic diseases. The differentiation of urticarial lesions may be made by considering the duration of an individual lesion longer than 24 hours, with burning and pain sensation in the lesions or lack of pruritus; skin marks such as postinflammatory pigmentation or purpura after resolution of the lesions; associated scaling or vehiculation in the lesions; systemic symptoms such as arthralgia, fever or fatigue; and several abnormal laboratory findings. The main differential diagnoses of annular urticarial lesions include urticarial vasculitis, autoinflammatory syndromes, hypersensitivity reactions, and connective tissue diseases.

Plasma-derived exosomes in chronic spontaneous urticaria induce the production of mediators by human mast cells

Mast cell activation and inflammatory mediators play central roles in the pathogenesis of chronic spontaneous urticaria (CSU). The factors that induce mast cell activation in CSU are still largely unknown. Exosomes are extracellular vesicles that activate mast cells. Here, we enriched exosomes derived from the plasma of healthy volunteers and CSU patients with antihistamine sensitivity (EXs-CSU-S) or resistance (EXs-CSU-R) using ultracentrifugation. We then incubated these exosomes with HMC-1 human mast cells. Notably, EXs-CSU-S and EXs-CSU-R increased tryptase-1 expression; histamine production; inflammatory mediator production; and Toll-like receptor-2 (TLR-2), TLR-4, and phospho-mitogen-activated protein kinase (MAPK) levels in HMC-1 cells. These effects were more significant in the EXs-CSU-R group than in the EXs-CSU-S group. TLR-2, TLR-4, and MAPK inhibitors (CC-401, TAK-715, and SCH772984, respectively) reduced EXs-CSU-Stimulated production of inflammatory mediators in HMC-1 cells. Overall, exosomes in the plasma of patients with CSU were found to activate mast cells and elicit the production of multiple inflammatory mediators, partly via the TLR-2, TLR-4, and MAPK pathways. Additionally, EXs-CSU-R had more powerful mast cell-activating and histamine-release abilities. Thus, these exosomes may be involved in the pathogenesis of CSU with antihistamine resistance.

Eosinophils, a Jack of All Trades in Immunity: Therapeutic Approaches for Correcting Their Functional Disorders

BACKGROUND AND OBJECTIVE

Eosinophils are primitive myeloid cells derived from bonemarrow precursors and require the intervention of interleukin (IL)-5 for their survival and persistence in blood and tissues. Under steady-state conditions, they contribute to immune regulation and homeostasis. Under pathological circumstances, eosinophils are involved in host protection against parasites and participate in allergy and inflammation.

DISCUSSION

Mostly, in asthma, eosinophils provoke airway damage via the release of granule contents and IL-13 with mucus hypersecretion and differentiation of goblet cells. Then, tissue remodeling follows with the secretion of transforming growth factor-β. Eosinophils are able to kill helminth larvae acting as antigen-presenting cells with the involvement of T helper (h)-2 cells and subsequent antibody response. However, they also exert pro-worm activity with the production of suppressive cytokine (IL- 10 and IL-4) and inhibition of nitric oxide. Eosinophils may play a pathogenic role in the course of chronic and autoimmune disease, e.g., inflammatory bowel disease and eosinophilic gastroenteritis, regulating Th2 responses and promoting a profibrotic effect. In atopic dermatitis, eosinophils are commonly detected and may be associated with disease severity. In cutaneous spontaneous urticaria, eosinophils participate in the formation of wheals, tissue remodeling and modifications of vascular permeability. With regard to tumor growth, it seems that IgE can exert anti-neoplastic surveillance via mast cell and eosinophil-mediated cytotoxicity, the so-called allergo-oncology. From a therapeutic point of view, monoclonal antibodies directed against IL-5 or the IL-5 receptors have been shown to be very effective in patients with severe asthma. Finally, as an alternative treatment, polyphenols for their anti-inflammatory and anti-allergic activities seem to be effective in reducing serum IgE and eosinophil count in bronchoalveolar lavage in murine asthma.

CONCLUSION

Eosinophils are cells endowed with multiple functions and their modulation with monoclonal antibodies and nutraceuticals may be effective in the treatment of chronic disease.

Mechanisms Governing Anaphylaxis: Inflammatory Cells, Mediators, Endothelial Gap Junctions and Beyond

Anaphylaxis is a severe, acute, life-threatening multisystem allergic reaction resulting from the release of a plethora of mediators from mast cells culminating in serious respiratory, cardiovascular and mucocutaneous manifestations that can be fatal. Medications, foods, latex, exercise, hormones (progesterone), and clonal mast cell disorders may be responsible. More recently, novel syndromes such as delayed reactions to red meat and hereditary alpha tryptasemia have been described. Anaphylaxis manifests as sudden onset urticaria, pruritus, flushing, erythema, angioedema (lips, tongue, airways, periphery), myocardial dysfunction (hypovolemia, distributive or mixed shock and arrhythmias), rhinitis, wheezing and stridor. Vomiting, diarrhea, scrotal edema, uterine cramps, vaginal bleeding, urinary incontinence, dizziness, seizures, confusion, and syncope may occur. The traditional (or classical) pathway is mediated via T cells, Th2 cytokines (such as IL-4 and 5), B cell production of IgE and subsequent crosslinking of the high affinity IgE receptor (FcεRI) on mast cells and basophils by IgE-antigen complexes, culminating in mast cell and basophil degranulation. Degranulation results in the release of preformed mediators (histamine, heparin, tryptase, chymase, carboxypeptidase, cathepsin G and tumor necrosis factor alpha (TNF-α), and of de novo synthesized ones such as lipid mediators (cysteinyl leukotrienes), platelet activating factor (PAF), cytokines and growth factors such as vascular endothelial growth factor (VEGF). Of these, histamine, tryptase, cathepsin G, TNF-α, LTC₄, PAF and VEGF can increase vascular permeability. Recent data suggest that mast cell-derived histamine and PAF can activate nitric oxide production from endothelium and set into motion a signaling cascade that leads to dilatation of blood vessels and dysfunction of the endothelial barrier. The latter, characterized by the opening of adherens junctions, leads to increased capillary permeability and fluid extravasation. These changes contribute to airway edema, hypovolemia, and distributive shock, with potentially fatal consequences. In this review, besides mechanisms (endotypes) underlying IgE-mediated anaphylaxis, we also provide a brief overview of IgG-, complement-, contact system-, cytokine- and mast cell-mediated reactions that can result in phenotypes resembling IgE-mediated anaphylaxis. Such classifications can lead the way to precision medicine approaches to the management of this complex disease.

Hepatic manifestations of drug reaction with eosinophilia and systemic symptoms syndrome

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a potentially life-threatening drug reaction, which can affect multiple organs. Patients with DRESS syndrome and hepatic manifestations may present alterations ranging from mild hepatitis to acute liver failure. The diagnosis might be difficult, and the management of these patients is challenging. This report analyzes a series of five cases reporting the clinical presentation, which ranged from acute hepatitis to liver failure, and discussed their treatment.

Coagulation status in patients with alopecia areata: a cross-sectional study

BACKGROUND

Alopecia areata (AA) is an autoimmune skin disease that causes non-scarring hair loss with lymphatic infiltration around and within follicles. There are interactions between inflammation and coagulation. The present study investigated the changes in coagulation status in patients with AA.

METHODS

In this study, the plasma level of three coagulation markers including fibrinogen, C-reactive protein (CRP), and D-dimer were measured in 30 patients (21 females 9 male) and 30 controls (21 females 9 male) matched by age and sex, and the results were compared between groups.

RESULTS

Plasma D-dimer levels were significantly higher in patients with AA (398.45±300 ng/mL vs. 244.4±129.92 ng/mL, P=0.014). Plasma fibrinogen and CRP levels were not significantly different between the two groups. There was no correlation between the plasma levels of the studied coagulation markers and the severity/duration of the disease, sex, and age.

CONCLUSIONS

As the present study was the first investigation on the coagulation status in patients with AA, elevated D-dimer levels in alopecia areata may suggest a deficient coagulation in these patients that may contribute to an increase in the risk of thrombosis. Further studies are needed to evaluate this hypothesis using a larger sample size.

Participation of the coagulation system and fibrinolysis as well as selected biomarkers in pathogenesis of chronic urticaria with various activity degree

Introduction

Chronic urticaria is a complex disease process in which chronic spontaneous urticaria (CSU) and chronic inducible urticaria are distinguished. Its etiopathogenesis still remains unknown. Some recent studies indicated a significant participation of vitamin D in the etiopathogenesis of urticaria. In 40–50% of patients with CSU on the basis of the positive result of the autologous serum skin test (ASST), autoimmunological background of the disease is diagnosed. Moreover, numerous test results confirm involvement of the coagulation system/fibrinolysis and non-infectious inflammatory factors in the pathophysiology of CSU.

Aim

To determine whether some factors may play a role in pathogenesis and contribute to the severity of chronic spontaneous urticaria.

Material and methods

One hundred and forty-two patients with diagnosed CSU were enrolled in the study. The activity of urticaria was assessed using the UAS-7 (Urticaria Activity Score). The study participants were divided into 4 groups depending on the UAS-7. ASST was performed and blood was collected to determine the biomarkers (CRP, vitamin D, D-dimers, fibrinogen, MPV, PLT).

Results

Statistical analysis was performed using Statistica 13. A statistically significant difference between groups with various activity of urticaria in D-dimer concentration average values (p < 0.05) was observed. Moreover, a statistically significant negative correlation between activity of urticaria and vitamin D concentration (p < 0.001) was noted.

Conclusions

Our results might support the possible involvement of both coagulation and fibrinolysis pathway and vitamin D in the urticaria pathomechanism. Further prospective studies in larger populations conducted at multiple centres are required to expand further our findings.

Current and Potential Biologic Drugs for the Treatment of Chronic Urticaria

This article reviews biologic treatments that are currently applied for the treatment of severe chronic urticaria. Monoclonal anti-immunoglobulin E (omalizumab) is effective and safe in many patients, but accessibility and cost constitute barriers to its wider use. Questions on the optimal duration of the treatment and possible symptom recurrences after discontinuing the drug are still raised. A discussion is presented about several other biologics currently under investigation with potential to be incorporated in the near future in patients with severe chronic urticaria.

The Relation of Autologous Serum Skin Test and Autologous Plasma Skin Test Result with Various Clinical and Laboratory Findings in Patients with Chronic Spontaneous Urticaria

Background

Despite the autologous serum skin test (ASST) and autologous plasma skin test (APST) is widely used test accessing whether a patient with chronic spontaneous urticaria (CSU) has autoreactivity or not, the clinician often encounter difficulty making correlation between the test result and clinical implications.

Objective

This study was aimed to find any clinical and laboratory findings related to the ASST and APST response. Agreement and correlation between the two tests was also analyzed.

Methods

A retrospective study was conducted on 300 CSU patients who underwent ASST, APST. The subjects were divided into four groups according to the skin test result. Also, the degree of serum and plasma response was recorded.

Results

Both ASST and APST positive group had shorter duration of the disease, higher incidence of at least one episode of angioedema than negative group. There were no significant differences in the positivity for autoantibodies including antinuclear, ds-DNA, and thyroid-related between the two groups. The predicted positive rate of ASST and APST according to age showed bimodal peak and decreasing pattern according to disease duration. Predicted positivity of both tests declined with increase in total immunoglobuline E (IgE) level. In the correlation study, the two tests showed high correlation coefficients.

Conclusion

ASST and APST positivity may be related to disease duration and severity of CSU. The two tests showed a generally consistent result. Autoreactivity may be gradually lost as disease continues. We suggest the autoreactivity in CSU could arise independently from IgE mediated immune process.

Urticaria and Angioedema Across the Ages

Chronic urticaria (CU) and angioedema can occur at any age. Although most CU with or without angioedema occurs in adults, it can also present in children or the elderly and can complicate pregnancy and breast-feeding. The presentations of CU and angioedema are different in children, middle-aged adults, and older patients as are the differential diagnoses. Therefore, the management of CU and angioedema in these different age groups and special populations needs to take into account the age-specific features of urticaria and angioedema. Here, we describe the evaluation, diagnosis, and treatment of CU and angioedema in children, middle-aged adults, and older patients. This review focuses on CU with or without angioedema and does not discuss acute urticaria or bradykinin-mediated angioedema.

Misunderstandings Between Platelets and Neutrophils Build in Chronic Inflammation

Regulated hemostasis, inflammation and innate immunity entail extensive interactions between platelets and neutrophils. Under physiological conditions, vascular inflammation offers a template for the establishment of effective intravascular immunity, with platelets providing neutrophils with an array of signals that increase their activation threshold, thus limiting collateral damage to tissues and promoting termination of the inflammatory response. By contrast, persistent systemic inflammation as observed in immune-mediated diseases, such as systemic vasculitides, systemic sclerosis, systemic lupus erythematosus or rheumatoid arthritis is characterized by platelet and neutrophil reciprocal activation, which ultimately culminates in the generation of thrombo-inflammatory lesions, fostering vascular injury and organ damage. Here, we discuss recent evidence regarding the multifaceted aspects of platelet-neutrophil interactions from bone marrow precursors to shed microparticles. Moreover, we analyse shared and disease-specific events due to an aberrant deployment of these interactions in human diseases. To restore communications between the pillars of the immune-hemostatic continuum constitutes a fascinating challenge for the near future.

Biomarkers In Chronic Spontaneous Urticaria: Current Targets And Clinical Implications

Chronic urticaria (CU) is a mast cell-driven disease characterized by the development of wheals, angioedema, or both for more than 6 weeks. The two major sub-types are chronic spontaneous urticaria (CSU) and inducible urticaria. In the last decade different pathophysiological mechanisms, potentially responsible for the development of the disease, have been described. It is likely that the activation of mast cells and basophils in CSU can be the results of immune system dysregulation, activation of the inflammatory cascade, and of the extrinsic coagulation pathway. Some of the mediators involved in the pathophysiological mechanisms of CSU have recently been identified as potential biomarkers useful for the diagnosis, follow-up, and management of the disease, even if they are not yet available in clinical practice. Thus, in this review we discuss new insights in the mediators involved in the pathogenesis of CSU, highlighting their potential role as biomarkers in the activity and progression of the disease and response to therapies.

New treatments for chronic urticaria

OBJECTIVE

Chronic urticaria (CU) is a common, heterogeneous, and debilitating disease. Antihistamines and omalizumab are the mainstay therapies of CU. Additional treatment options are needed. Here, we review the off and beyond label use of licensed drugs, novel treatments that are currently under development, and promising new targets.

DATA SOURCES

MEDLINE was searched for recent reports of the successful use of treatments in CU and promising targets for the development of novel treatment options. We also searched ClinicalTrials.gov for recent and ongoing randomized clinical trials in CU.

STUDY SELECTIONS

Relevant articles were selected and reviewed.

RESULTS

Omalizumab, the treatment of choice in patients with antihistamine-resistant chronic spontaneous urticaria (CSU), should be explored for use in chronic inducible urticaria in children younger than 12 years with CSU and at higher doses. The off-label use of dupilumab, reslizumab, mepolizumab, and benralizumab can be effective in CU. Ligelizumab and UB-221, 2 novel anti-IgE monoclonal antibodies, are in clinical trials for CU. Other promising drugs that are currently under development for CU are a chemoattractant receptor-homologous molecule expressed on T_H2 cell antagonist, a monoclonal antibody to Siglec-8 (AK002), Bruton tyrosine kinase inhibitors (fenebrutinib and Lou064), a spleen tyrosine kinase inhibitor, and dupilumab. Promising targets of future therapies include the Mas-related G-protein-coupled receptor X2; the histamine₄ receptor; C5a and its receptor; inhibitory mast cell receptors other than Siglec-8; interleukin 33, interleukin 25, and thymic stromal lymphopoietin, and stem cell factor.

CONCLUSION

Novel and better treatments for CU are very much needed. Some agents are in clinical trials already (eg, ligelizumab), and additional ones should be developed, making use of the many promising targets recently identified and characterized.

Increased expression of L-plastin in nasal polyp of patients with nonsteroidal anti-inflammatory drug-exacerbated respiratory disease

BACKGROUND

Most patients with nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (NERD) suffer from recurrence of nasal polyps. However, little is known about the specific cellular and molecular mechanisms contributing to the pathogenesis of nasal polyp development in patients with NERD in particular, especially at baseline when cyclooxygenase 1 inhibitors are not present. The objectives of this study were to identify proteins involved in the pathogenesis of nasal polyps in patients with NERD.

METHODS

We collected nasal polyp tissue from patients with NERD and from patients with aspirin-tolerant chronic rhinosinusitis with nasal polyps (CRSwNP). Protein profiles were analyzed by 2-dimensional electrophoresis and identified several proteins, including L-plastin, as highly expressed. We examined L-plastin and tissue factor (TF) expression by immunohistochemical and immunofluorescence analyses. To examine the role of L-plastin in eosinophils, we knocked down L-plastin expression in Eol-1 cells by using siRNA transfection.

RESULTS

L-plastin protein levels in nasal polyp tissue were increased in patients with NERD relative to those in patients with aspirin tolerant CRSwNP. Immunofluorescence analysis revealed that L-plastin was dominantly expressed in eosinophils and L-plastin and TF were co-expressed in eosinophils in NERD nasal polyp tissue. Knockdown of L-plastin in Eol-1 cells disrupted the cell surface distribution of TF by stimulation with granulocyte macrophage colony-stimulating factor.

CONCLUSION

Increased expression of L-plastin by eosinophils may contribute to abnormal fibrin deposition through TF translocation to the eosinophil cell surface in NERD nasal polyp tissue, which in turn may contribute to the pathogenesis of NERD.

Coagulation and Skin Autoimmunity

Several lines of evidence indicate that the immune system, inflammation, and coagulation are simultaneously activated in autoimmune and immune-mediated skin diseases. Pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-alpha induce the expression of the main initiator of coagulation, i.e., tissue factor. The proteases of coagulation in turn act on protease-activated receptors inducing the expression of various pro-inflammatory cytokines triggering inflammation. The cross-talk among immune system, inflammation, and coagulation amplifies and maintains the activation of all three pathways. This review focuses on three skin disorders as chronic spontaneous urticaria (CSU), angioedema, and bullous pemphigoid (BP), in which the relationships among the three systems have been investigated or their clinical consequences are relevant. Markers of thrombin generation, fibrinolysis, and inflammation have been reported to be increased in the plasma during flares of CSU and angioedema, as well as in the active phase of BP, with the marker levels reverting to normal during remission. The coagulation activation seems to be important only at local level in CSU and angioedema while both at local and systemic levels in BP which is the only condition associated with an increased thrombotic risk. The prothrombotic state in autoimmune skin diseases raises the question of the indication of anticoagulant treatment, particularly in the presence of other cardiovascular risk factors.

Headache deteriorates the quality of life in children with chronic spontaneous urticaria

BACKGROUND

Quality of life, which is impaired in patients with chronic spontaneous urticaria (CSU), is influenced by comorbid mental disorders. Headaches could be another comorbid mental disorder that affects quality of life in children with CSU.

OBJECTIVES

To investigate the effect of headaches on urticaria symptoms, disease activity and quality of life in children with CSU.

METHODS

A total of 83 patients with CSU were enrolled in the study and were separated into two groups as those with or without headache. Demographic and clinical characteristics were studied with the Urticaria Activity Score (UAS7), Urticaria Control test (UCT) and Chronic Urticaria Quality of Life Questionnaire (CU-Q2QoL). The headache questionnaire designed according to the Department of International Classification of Headache Disorders, second edition (ICHD-II) was used and VAS (Visual Analogue Scale) and NRS (Numerical Rating Scale) were used to assess the pain measurement. In patients diagnosed with migraine, the paediatric Migraine Disability Assessment Scale (PedMIDAS) was applied.

RESULTS

CU-QoL total scores were significantly higher in patients with CSU with headache than in those without headache (p=0.015). In the five domains of CU-QoL, impact of daily life activities domain and sleep problems domain had higher scores in CSU with headache (p=0.008, 0.028, respectively). There was no significant relationship between UCT, UAS and CU-QoL and headache severity (p<0.05). No differences were found between the groups in respect of duration of urticaria, UAS7 and UCT.

CONCLUSION

Headache may be an important factor that affects and impairs quality of life in children with chronic urticaria.

Interplay between acute phase response and coagulation/fibrinolysis in chronic spontaneous urticaria

Background

Chronic spontaneous urticaria (CSU) is associated with activation of systemic inflammatory response and coagulation/fibrinolysis.

Aim

To study whether there is a relationship between the acute phase response and coagulation/fibrinolysis in chronic spontaneous urticaria (CSU) patients.

Methods

Serum concentrations of C-reactive protein (CRP) and interleukin 6 (IL-6), key markers of acute phase response and of D-dimer, a marker of fibrin turnover were investigated in 58 CSU patients assessed with the urticaria activity score (UAS) and the controls.

Results

Serum concentrations of IL-6, CRP, and D-dimer were significantly higher in CSU patients as compared with the controls. We found statistically significant correlations between D-dimers concentrations and the inflammatory markers: CRP and IL-6 as well as UAS.

Conclusions

Markers of inflammation (IL-6 and CRP) and of fibrinolysis (D-dimer) are related to each other in CSU, suggesting a possible cross-talk between inflammation and coagulation/fibrinolysis. It might be implicated in pathogenesis of the disease and may be associated with higher risks of cardiovascular diseases in CSU patients.

Eosinophils from Physiology to Disease: A Comprehensive Review

Despite being the second least represented granulocyte subpopulation in the circulating blood, eosinophils are receiving a growing interest from the scientific community, due to their complex pathophysiological role in a broad range of local and systemic inflammatory diseases as well as in cancer and thrombosis. Eosinophils are crucial for the control of parasitic infections, but increasing evidence suggests that they are also involved in vital defensive tasks against bacterial and viral pathogens including HIV. On the other side of the coin, eosinophil potential to provide a strong defensive response against invading microbes through the release of a large array of compounds can prove toxic to the host tissues and dysregulate haemostasis. Increasing knowledge of eosinophil biological behaviour is leading to major changes in established paradigms for the classification and diagnosis of several allergic and autoimmune diseases and has paved the way to a "golden age" of eosinophil-targeted agents. In this review, we provide a comprehensive update on the pathophysiological role of eosinophils in host defence, inflammation, and cancer and discuss potential clinical implications in light of recent therapeutic advances.

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.

In chronic spontaneous urticaria, high numbers of dermal endothelial cells, but not mast cells, are linked to recurrent angio-oedema

BACKGROUND

Chronic spontaneous urticaria (CSU) is an inflammatory skin disorder characterized by recurrent weals, angio-oedema or both. Recent studies have shown that the number of endothelial cells is increased in the skin of patients with CSU, but the underlying mechanisms and clinical implications of this are unclear.

AIM

To evaluate whether mast cell (MC) or endothelial cell (EC) numbers correlate with CSU and whether they are relevant for disease duration, disease activity or the presence of clinical features.

METHODS

We determined the numbers of CD31+ ECs and MCs in nonlesional skin of 30 patients with CSU using quantitative histomorphometry, and assessed their correlation with each other and with clinical features such as disease duration, disease activity and occurrence of angio-oedema.

RESULTS

The numbers of MCs and ECs were high in the nonlesional skin of patients with CSU, but did not correlate with each other. Neither MC number nor EC number correlated with disease duration or disease activity. Interestingly, patients with high numbers of cutaneous CD31+ ECs had higher rates of recurrent angio-oedema and vice versa.

CONCLUSIONS

Based on these findings, we speculate that vascular remodelling and MC hyperplasia in patients with CSU occurs independently and via different mechanisms. Targeting of the mechanisms that drive neoangiogenesis in CSU may result in novel therapeutic strategies for the management of patients with angio-oedema.

Mediators of Inflammation and Angiogenesis in Chronic Spontaneous Urticaria: Are They Potential Biomarkers of the Disease?

In chronic spontaneous urticaria (CSU), different pathophysiological mechanisms, potentially responsible for the development of the disease, have been recently described. It is likely that the activation of skin mast cells with consequent release of histamine and other proinflammatory mediators is responsible for vasodilation in the lesional skin of CSU. However, the underlying causes of mast cell activation in the disease are largely unknown and remain to be identified. Thus, in this review, we discuss new insights in the pathogenesis of CSU, focusing on inflammation and angiogenesis. The understanding of these mechanisms will enable the identification of biomarkers useful for the diagnosis, follow-up, and management of CSU and will allow the development of novel, more specific, and patient-tailored therapies.

Correlation between the histopathology of chronic urticaria and its clinical picture

BACKGROUND

Chronic urticaria is characterized by transient, pruritic lesions of varying sizes, with central pallor and well-defined edges, with disease duration longer than six weeks. Its cellular infiltrate consists of neutrophils, lymphocytes and eosinophils. There is a subgroup of patients with eosinophilic or neutrophilic urticaria, resistant to the treatment with antihistamines, but that respond to a combination of antihistamine with other drugs.

OBJECTIVE

To evaluate the present infiltration in chronic urticaria biopsies and correlate it with the clinical disease activity and response to treatment.

METHODS

Forty-one patients with chronic urticaria were classified according to the score of severity of the disease, response to treatment and type of perivascular infiltrate. Inflammatory infiltrates were divided in eosinophilic (46.30%), neutrophilic and mixed.

RESULTS

An association was found between the eosinophilic infiltrate and clinical scores of greater severity (p = 0.002).

CONCLUSION

This association shows that the eosinophilic inflammatory infiltrates denote high clinical activity, which means more severe and exuberant clinical pictures of the disease.

Mechanisms of action that contribute to efficacy of omalizumab in chronic spontaneous urticaria

The monoclonal anti-immunoglobulin E (IgE) antibody, omalizumab, was the first drug approved for use in patients with chronic idiopathic/spontaneous urticaria (CIU/CSU) who remain symptomatic despite H₁ -antihistamine treatment. Omalizumab binds to free IgE, which lowers free IgE levels and causes FcεRI receptors on basophils and mast cells to be downregulated. It has been shown to improve symptoms of CIU/CSU, but its mechanism of action is not currently understood. Potential mechanisms in CIU/CSU include reducing mast cell releasability, reversing basopenia and improving basophil IgE receptor function, reducing activity of IgG autoantibodies against FcεRI and IgE, reducing activity of IgE autoantibodies against an antigen or autoantigen that has yet to be definitively identified, reducing the activity of intrinsically 'abnormal' IgE, and decreasing in vitro coagulation abnormalities associated with disease activity. However, none of these theories alone or in combination fully account for the pattern of symptom improvement seen with omalizumab therapy, and therefore, no one mechanism is likely to be the definitive mechanism of action. Additional research is needed to further clarify the involvement of omalizumab in relieving symptoms associated with the complex, multifactorial pathogenesis of CIU/CSU.

Looking forward to new targeted treatments for chronic spontaneous urticaria

The introduction of omalizumab to the management of chronic spontaneous urticaria (CSU) has markedly improved the therapeutic possibilities for both, patients and physicians dealing with this disabling disease. But there is still a hard core of patients who do not tolerate or benefit from existing therapies and who require effective treatment. Novel approaches include the use of currently available drugs off-licence, investigational drugs currently undergoing clinical trials and exploring the potential for therapies directed at pathophysiological targets in CSU. Off-licence uses of currently available drugs include rituximab and tumour necrosis factor inhibitors. Ligelizumab (anti-IgE), canakinumab (anti-IL-1), AZD1981 (a PGD2 receptor antagonist) and GSK 2646264 (a selective Syk inhibitor) are currently in clinical trials for CSU. Examples of drugs that could target potential pathophysiological targets in CSU include substance P antagonists, designed ankyrin repeat proteins, C5a/C5a receptor inhibitors, anti-IL-4, anti-IL-5 and anti-IL-13 and drugs that target inhibitory mast cell receptors. Other mediators and receptors of likely pathogenic relevance should be explored in skin profiling and functional proof of concept studies. The exploration of novel therapeutic targets for their role and relevance in CSU should help to achieve a better understanding of its etiopathogenesis.

Chronic Spontaneous Urticaria: Pathogenesis and Treatment Considerations

The treatment of chronic spontaneous urticaria begins with antihistamines; however, the dose required typically exceeds that recommended for allergic rhinitis. Second-generation, relatively non-sedating H₁-receptor blockers are typically employed up to 4 times a day. First-generation antihistamines, such as hydroxyzine or diphenhydramine (Atarax or Benadryl), were employed similarly in the past. Should high-dose antihistamines fail to control symptoms (at least 50%), omalizumab at 300 mg/month is the next step. This is effective in 70% of antihistamine-refractory patients. H₂-receptor blockers and leukotriene antagonists are no longer recommended; they add little and the literature does not support significant efficacy. For those patients who are unresponsive to both antihistamines and omalizumab, cyclosporine is recommended next. This is similarly effective in 65%–70% of patients; however, care is needed regarding possible side-effects on blood pressure and renal function. Corticosteroids should not be employed chronically due to cumulative toxicity that is dose and time dependent. Brief courses of steroid e.g., 3–10 days can be employed for severe exacerbations, but should be an infrequent occurrence. Finally, other agents, such as dapsone or sulfasalazine, can be tried for those patients unresponsive to antihistamines, omalizumab, and cyclosporine.

IgE-associated allergic disorders: recent advances in etiology, diagnosis, and treatment

IgE-associated allergic diseases belong to the most common inflammatory conditions. Their clinical manifestation ranges from mild symptoms to life-threatening episodes. Often patients experience a reduction in physical and psychologic well-being and suffer from a decreased quality of life due to disease activity. The continuously rising number of people that are affected by an allergic condition indicates an urgent need for better diagnostics and more efficient treatment options. Recent progress in the understanding of pathophysiologic mechanisms underlying IgE-associated allergic disorders has led to the identification of novel therapeutic targets and the development of drug candidates that are currently under evaluation. In this review, we highlight studies and clinical trials, which have helped to gain further insight in the etiology of IgE-associated allergic conditions as well as advances in the development of diagnostic tools and therapeutic approaches recently published in Allergy (European Journal of Allergy and Clinical Immunology).

Autologous serum and plasma skin test to predict 2-year outcome in chronic spontaneous urticaria

Background

Autologous serum skin test (ASST) and autologous plasma skin test (APST) are simple methods to diagnose autoimmune chronic urticaria. However, the association data of ASST or APST with disease severity and long-term outcome are still unclear.

Objective

The results of ASST and APST might be used to predict urticaria symptom severity and long-term outcomes among chronic spontaneous urticaria (CSU) patients.

Methods

We evaluated the prevalence of reactive ASST and APST in 128 CSU patients. The patients were characterized by 4 groups: negative, ASST positive, APST positive, and both ASST and APST positive. We observed remission rate among the CSU patients during 2 years.

Results

Forty-four of 128 CSU patients (34%) had negative autologous skin test. The CSU patients with positive ASST, positive APST, and both positive ASST and APST were 47 (37%), 6 (5%), and 31 (24%), respectively. No significant difference was found between the groups according to urticaria severity score (USS) and dermatology life quality index (DLQI). Mean wheal diameter of ASST showed positive correlation with DLQI. Also, mean wheal diameter of APST showed positive correlation with USS and DLQI. Both the positive ASST and APST groups had a high proportion of 4-fold dose of H1-antihistamine than the positive ASST (p = 0.03) and negative groups (p = 0.0009). The rate of remission over 2 years in the negative, positive ASST, positive APST, and both positive ASST and APST groups were 81.1%, 62.3%, 60%, and 46.1%, respectively. The urticaria remission rate in patients in the negative group was significantly higher compared with both positive ASST and APST groups (odds ratio, 5.0; 95% confidence interval, 1.61–15.44; p = 0.006).

Conclusion

ASST and APST results could predict remission rates among patients with CSU. Our results suggested investigating ASST and APST among CSU patients before starting treatment.

Comorbidity and pathogenic links of chronic spontaneous urticaria and systemic lupus erythematosus--a systematic review

Chronic spontaneous urticaria (CSU) is a common mast cell-driven disease characterized by the development of wheals (hives), angioedema (AE), or both for > 6 weeks. It is thought that autoimmunity is a common cause of CSU, which is often associated with autoimmune thyroiditis, whereas the link to other autoimmune disorders such as systemic lupus erythematosus (SLE) has not been carefully explored. Here, we systematically reviewed the existing literature for information on the prevalence of CSU in SLE (and vice versa) and we examined the possible clinical and pathogenetic relationship between CSU and SLE. The prevalence of CSU and CSU-like rash in SLE was investigated by 42 independent studies and comorbidity in adult patients reportedly ranged from 0% to 21.9% and 0.4% to 27.5%, respectively (urticarial vasculitis: 0-20%). In children with SLE, CSU was reported in 0-1.2% and CSU-like rash in 4.5-12% (urticarial vasculitis: 0-2.2%). In contrast, little information is available on the prevalence of SLE in patients with CSU, and more studies are needed to determine the rate of comorbidity. Recent insights on IgG- and IgE-mediated autoreactivity suggest similarities in the pathogenesis of CSU and SLE linking inflammation and autoimmunity with the activation of the complement and coagulation system. Future studies of patients with either or both conditions could help to better define common pathomechanisms in CSU and SLE and to develop novel targeted treatment options for patients with CSU and SLE.

Chronic spontaneous urticaria and internal parasites--a systematic review

Chronic spontaneous urticaria (CSU) is defined as persistent wheals, angioedema, or both lasting for >6 weeks due to known or unknown causes. Some epidemiological studies and case reports suggest that internal parasite infections (PI) can cause CSU. Here, we provide a systematic overview of published findings on the prevalence and relevance of PI in CSU and we discuss possible pathomechanisms. The prevalence of PI in CSU was investigated by 39 independent studies and comorbidity reportedly ranged from 0 to 75.4% (two-thirds of these studies reported infection rates of 10% or less). The prevalence of PI in adult and pediatric CSU patients ranged from 0% to 75.4% and from 0% to 37.8%, respectively. CSU patients were more often diagnosed with protozoa and had a significantly higher risk of toxocariasis seropositivity and Anisakis simplex sensitization when compared to healthy controls. Patients with chronic urticaria more frequently had seropositivity of fasciolosis, Anisakis simplex sensitization, and the presence of Blastocystis hominis allele 34 (ST3) as compared with control subjects. In 21 studies, efficacy of treatment with antiparasitic drugs ranged from 0 to 100% (35.7% of 269 CSU patients benefitted). In 9 (42.8%) of 21 studies, more than 50% of efficacy was observed. The reported rate of urticaria comorbidity in PI patients in 18 independent studies is 1-66.7%. Urticaria including CSU might be a quite common symptom of strongyloidiasis and blastocystosis. Pathogenic mechanisms in CSU due to PI may include specific IgE, Th2 cytokine skewing, eosinophils, activation of the complement, and the coagulation systems.