Identification of the etiologies of chronic urticaria in children: a prospective study of 94 patients

The prevelance of food allergy in patients with chronic idiopathic urticaria: a systematic review and meta-analysis

Chronic idiopathic urticaria (CIU) is difficult for patients and healthcare professionals to manage owing to its chronic and unpredictable nature. While the exact cause of CIU is unknown, it is suggested that food allergies may contribute to the development of symptoms. To determine the prevalence of food allergy in patients diagnosed with CIU. This systematic review is reported in accordance with PRISMA guidelines. We included all relevant articles published from inception to April 2023 in Scopus, Midline, and Web of Science. The initial search yielded 282 articles, of which only seven were included after applying the inclusion and exclusion criteria. The systematic review included a total of 1551 patients with urticaria. Approximately 25% of patients with food allergies had CIU. The prevalence of a family history of atopy was 37.9% (range, 24.3-53.8%, P = 0.133). There was a significant risk of angioedema in patients with urticaria (P = 0.039). The risk of CIU among patients with food allergies was estimated to be one in every four patients with urticaria, with a similar risk among the adult and pediatric populations. Patients with food allergies and a history of atopy were at higher risk of CIU. Angioedema is a common concomitant manifestation associated with common urticaria. This knowledge is important to identify patients at higher risk of urticaria and implement the necessary management to minimize potential complications and maintain a controlled disease.

Chronic Urticaria in Children: A Single-Center Retrospective Study From Turkey

The studies on childhood chronic urticaria (CU) are limited. We aimed to investigate the epidemiological and etiological factors of children with CU. Demographic characteristics, laboratory findings, and etiological factors of patients diagnosed with CU younger than the age of 18 were retrospectively evaluated. Of the 124 participants, 68 (54.8%) were aged 12 and older. Angioedema accompanied 18.5% of the patients. Chronic spontaneous urticaria (CSU) was found in 75%, while 24.2% had chronic inducible urticaria. Symptomatic dermographism (16.1%) was the most common among chronic inducible urticaria, followed by cholinergic urticaria (4.8%). No etiological factor could be detected in 56.5% of the children. Infections (29.8%) were the most common etiological factor, followed by drugs (8%). Dental problems (16.9%) were the primary infections associated with CU. Chronic urticaria prevalence in children increased with age, with CSU being the most common type. Infections played a significant role in childhood CU.

Clinical Characteristics, Investigations and Treatment in Children with Chronic Urticaria: An Observational Study

Background and Objectives: The guidelines for chronic urticaria in children contain recommendations that are often based on adult studies. The diagnostic pathway has not been standardized and the effectiveness of anti-H1, omalizumab, montelukast, and systemic glucocorticoids is rarely reported in the pediatric population. There is a wide variation in the rate of remission of chronic urticaria between studies. The aim of this study is to enhance our understanding of pediatric chronic urticaria. Materials and Methods: This study enrolled 37 children with chronic urticaria aged from 0 to 18 years. Demographic parameters, medical history, clinical features, laboratory data and treatment information were collected. Children were treated with the recommended dosage of second-generation H1-antihistamines, which was increased by up to twofold. Omalizumab was added for refractory anti-H1 patients. A three-day course with systemic glucocorticoids was administered for severe exacerbations. Montelukast was administered to some children. Results: Wheals without angioedema were common. Chronic urticaria was spontaneous in 32 children (86.48%), inducible in 2 (5.41%), induced by a parasite in 1 and vasculitic in 2. Treatment of the potential causes of chronic urticaria was of no benefit, except for eradication of Dientamoeba fragilis. Chronic urticaria was resolved within three years in 45.9% of cases. Allergic diseases were present in nine children (24.32%) and autoimmune diseases were present in three (8.11%). All children were treated with anti-H1 at the licensed dose or at a higher dose. A partial or complete response to anti-H1 was observed in 29 (78.38%) patients. Montelukast showed no benefit. All children treated with omalizumab responded. Systemic glucocorticoids were successfully used to treat exacerbations. Conclusions: Our findings indicate that laboratory tests should not be routinely performed in children with chronic urticaria without clinical suspicion. However, comorbidities such as thyroid autoimmune disease and coeliac disease are suggested to be monitored over the chronic urticaria course. These clinical conditions could be diagnosed from the diagnostic framework of chronic urticaria. Increasing the dosage of anti-H1 and omalizumab was effective in children resistant to standard treatment but we still need further studies to generate a standard patient-centered treatment.

Evaluation of Pediatric Chronic Urticaria with Emphasis on Clinical and Laboratory Characteristics and Treatment Response to Omalizumab: A Real-Life Experience from a Tertiary Allergy Center

Pediatric data on the clinical and etiologic features, treatment response, and use of omalizumab for chronic urticaria (CU) are quite limited. The aim of this study was to evaluate the clinical and demographic characteristics, laboratory findings, and response to treatment of CU in children. Children with a diagnosis of CU between 2019 and 2023 were included in the study. Information on demographic characteristics, clinical features, laboratory tests, provocation tests for inducible urticaria, urticaria activity scores (UAS7), and treatment responses were obtained from patients' medical records. A total of 150 children (50.7% male) with CU were enrolled in the study. A total of 14 (9.3%) patients had autoimmune diseases of which 11 (7.3%) had autoimmune thyroiditis. Overall, 97 (64.7%) patients had chronic spontaneous urticaria (CSU) and 53 (35.3%) had chronic inducible urticaria. A total of 16 patients who remained symptomatic despite high-dose antihistamines were treated with omalizumab, with a good response in 13 (81.3%) and a partial response in 3 (18.7%) patients. CSU accounts for the majority of pediatric CU, with the etiology being in part related to an autoimmune background. This study provides an overview of CU in children and demonstrates the safety and efficacy of treatment with omalizumab.

Clinical features of patients with chronic spontaneous urticaria associated with autoimmune thyroiditis

The aim of the study was to focus on children with both chronic spontaneous urticaria (CSU) and autoimmune thyroiditis (AT) as this topic is rarely studied in children although some publications show a higher proportion of antithyroid antibodies in children with CSU. We highlight two cases of children with both CSU and AT and compare their data with reports from the literature. Since only case reports or case series were available, we performed a descriptive analysis of 15 patients. There were 7 (46.7%) cases of hypothyroidism and the rest were euthyroid. Hypothyroidism appears before, during, and after the diagnostic of CSU. One patient with hypothyroidism and one with euthyroidism receiving l-thyroxine experienced remission of urticaria. Three patients over 12 years of age (20%) received omalizumab. Three patients (20%) had another autoimmune disease and seven (58.3%) had a family history of thyroid disease or autoimmune disease. CONCLUSION: Children with CSU need repeated testing for antithyroid antibodies. Children with both CSU and AT require close medical supervision focused on the development of other autoimmune diseases. l-thyroxine may improve urticaria in patients with hypothyroidism, but there is not enough evidence for patients with euthyroidism. Omalizumab may be of benefit in this population but well-controlled studies in children with AT and CSU are needed.

Pediatric chronic urticaria: Clinical and laboratory characteristics and factors linked to remission

BACKGROUND

Chronic urticaria (CU) is defined as the occurrence of wheals/angioedema for ≥6 consecutive weeks. Until now, guidelines and publications addressing CU have focused mainly on adults. As a result, evidence and guidance in the pediatric population are scarce.

METHODS

This study aims to describe clinical and laboratory findings in pediatric CU and to determine factors associated with remission.

RESULTS

185 patients, 54% female, median age at onset of 8.8 years. Angioedema was present in almost half. The most common type of CU was chronic spontaneous urticaria (CSU) in 74%. At least one atopic comorbidity was found in almost a third (35%). In addition, 8% had an autoimmune disorder (exclusively in CSU) and 9% had a psychiatric condition. Basopenia was found in 67% and was more frequently associated with CSU. The basophil activation test (BAT) was positive in 40%. With regard to remission, being of male sex, angioedema absence, the absence of physical triggers, and eosinophil counts >0.51 × 109 /L were associated with shorter CU duration.

CONCLUSION

Atopy is a common condition in pediatric CU. CSU is the most common type. Autoimmune comorbidities and basopenia were significantly more common in CSU. In addition, ours is one of the few studies, assessing BAT utility in the pediatric population, being positive in a relevant percentage (40%). BAT positivity was more frequent in CSU. Our results suggest that the absence of angioedema and physical triggers, male sex, and eosinophil counts >0.51 × 109 /L appear to be associated with a better prognosis in terms of remission.

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

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

Possible microRNA-based mechanism underlying relationship between chronic spontaneous urticaria and Blastocystis

BACKGROUND

Blastocystis spp. has been proposed as a possible cause of extraintestinal clinical signs such as urticaria pathogenesis.

OBJECTIVES

The aim of this study was to investigate the differences between microRNA (miRNA) expression profiles of Chronic spontaneous urticaria (CSU) patients in the presence or absence of Blastocystis spp. as well as healthy controls. Additionally, cellular pathways which are affected in the presence of Blastocystis spp. were identified.

METHODS

Twenty patients diagnosed with CSU were enrolled in the study and divided into equally two groups according to the presence of Blastocystis spp. Besides, six healthy individuals were included in the study. The expression profiles of 372 human-derived miRNAs have been investigated in serum samples from CSU patients and healthy controls with miScript miRNA PCR Array Human miRBase Profiler.

RESULTS

Compared to Blastocystis-negative (BN)-CSU patients, expression of 3 miRNAs (hsa-miR-3183, hsa-miR-4469, hsa-miR-5191) were found to be downregulated by at least two-fold (p < 0.05) in Blastocystis-positive (BP)-CSU patients. Additionally, the miRNA expression profiles of six healthy individuals (n = 3 Blastocystis-positive, n = 3 Blastocystis-negative) were analyzed and it was determined that the expressions of 7 miRNAs (hsa-miR-4661-5p, hsa-miR-4666a-5p, hsa-miR-4803, hsa-miR-5587-5p, hsa-miR-4500, hsa-miR-5680, hsa-miR-382-3p) increased at least 3-fold in the serum of individuals with Blastocystis-positive compared to Blastocystis-negative subjects. Most down-regulated miRNAs, in BP-CSU patients, affect cell adhesion molecules (CAMs), and signaling pathways therefore, Blastocystis spp. presence may influence the clinical presentation of urticaria by leading to unbalanced immunity. In addition, Blastocystis spp. presence may be influenced TGF- β signaling pathway through altered miRNAs and may be laying the groundwork for the development of CSU in healthy individuals.

CONCLUSIONS

As a consequence, this is the first report to show that the miRNA expression profile is affected by the presence of Blastocystis spp. Further miRNA-based studies are needed in order to enlighten the exact underlying molecular mechanisms of the relationship between Blastocystis spp. and CSU.

Comorbidities of Chronic Urticaria: A glimpse into a complex relationship

Chronic Urticaria (CU) is a chronic inflammatory, predominantly mast cell-driven disease, characterized by the development of wheals and/or angioedema for more than 6 weeks. It affects approximately 1%-5% of the total population worldwide and imposes a substantial burden on health-related quality of life, significantly affecting patients' daily life. The economic impact on the health system is also not negligible, with an estimated cost per patient per year of approximately 2.000 $ in the United States. Although the underlying pathophysiology is not fully explored, autoimmune mechanisms have been proposed, including type I ("autoallergy" by means of autoantibodies to self-antigens) and type IIb (autoimmunity). Atopic, autoimmune, and psychiatric disorders are prevalent comorbidities in both children and adults with Chronic Spontaneous Urticaria (CSU). Although malignancies, cardiovascular diseases and other comorbidities have also been reported as associated diseases in patients with CSU, data remain scarce. It is still unknown whether the aforementioned comorbidities share common pathophysiological mechanisms with specific endotypes of CSU. The current review aims to overview current data on comorbidities of CU, and furthermore to comment on the potential linked pathways underlying these diseases.

Urticaria in a Pediatric Population: A Portuguese Single-Center Cohort Report

Background

Urticaria typically involves the skin and mucosa and is characterized by the development of wheals, angioedema, or both. According to the temporal evolution of the lesions, urticaria is classified as acute (AU) or chronic (CU), depending on whether the episodes last for fewer or more than six weeks, respectively. This study aimed to characterize a group of children and adolescents with urticaria and describe its subtypes, associated comorbidities, treatment, and evolution.

Methodology

This retrospective, observational study included patients aged <18 years who were diagnosed with urticaria in a tertiary teaching hospital in Portugal, and followed up in a Pediatric Allergy Unit, between January 2019 and December 2021.

Results

A total of 43 patients, aged nine months to 16 years were included. Of these, 22 (51%) were males. AU was identified in 12 (28%) cases, chronic spontaneous urticaria in 21 (63%), and physical urticaria (to cold) in four (9%). Autoantibodies were detected in four patients with spontaneous urticaria. In 6% of patients with CU, the episodes were associated with angioedema. Most CU episodes were successfully managed with the recommended or double the recommended dose (48%) of H1 antihistamines. Three patients requiring fourfold higher than the recommended dose of H1 antihistamines remained unresponsive and were started on omalizumab. Associated autoimmune thyroiditis was diagnosed in four patients.

Conclusions

In this cohort of patients, urticaria was equally distributed between the genders and the first-line therapy was second-generation antihistamines, consistent with current guidelines. Universal screening for autoimmune diseases in patients with chronic spontaneous urticaria revealed four cases of thyroiditis, which supports the relevance of this approach when managing CU.

Natural History and Influencing Factors of Chronic Urticaria in Children

Purpose

Chronic urticaria (CU) can reduce the quality of life of children and their parents, but there are only a few studies on the course of CU in children. This study aimed to investigate the natural course of CU in children and identify the factors that influence its prognosis.

Methods

We evaluated 77 children diagnosed with CU, who were monitored for at least 48 months. Subjects were classified as either chronic spontaneous urticaria (CSU) or other CU, and the clinical features were compared. Remission was defined as having no symptoms without treatment for more than 1 year. The remission rate was analyzed, and the factors influencing the prognosis were investigated.

Results

The average age of the study population was 5.96 ± 4.06 years, and 64 (83.1%) patients had CSU. The remission rates at 6 months, 1 year, 2 years, 3 years, and 4 years after symptom onset were 22.1%, 40.3%, 52.0%, 63.7%, and 70.2%, respectively, for children with CU. For children with CSU, these values were 23.4%, 43.7%, 56.2%, 68.7%, and 75.0%, respectively. The total serum immunoglobulin E (IgE) levels were positively correlated with disease duration (r = 0.262, P = 0.021); no other factors were associated with the duration of the disease.

Conclusions

A high proportion of children with CU were classified as CSU. No indicators, except for total IgE were found to predict the timing of spontaneous remission. The CU remission rate identified in this study is expected to be used as one of the reference data for the progress of CU in patients.

An evaluation of the factors affecting the clinical and laboratory findings, prognosis, and treatment response in children with chronic urticaria

Chronic urticaria (CU) is a rare disease in childhood, and studies in children are limited. In this study, the aim was to investigate the clinical and laboratory findings and demographic characteristics of children with CU and to determine the factors affecting prognosis. The study included 141 patients aged 0-18 years who were diagnosed with CU in the pediatric allergy outpatient clinic between January 1, 2013, and December 31, 2018. Risk factors related to prognosis were investigated by comparing the duration of CU and treatment response with clinical and etiological features. IBM SPSS version 24 was used for statistical analyses. In the study group, the female/male ratio was 69/55, and the median age at first visit was 9.5 years (min:1, max:17). Among patients, 63 (44.5%) had an accompanying atopic disease, and 23 (16.3%) had chronic disease. Of the patients, 124 (88%) had chronic spontaneous urticaria, and 17 patients (12%) had chronic inducible urticaria (CIU). Of those with CIU, 72.2% had symptomatic dermographism, 16.7% had cholinergic urticaria, and 11.1% had cold urticaria. After the evaluations, the most common pathological findings in our patients were intestinal parasitosis (n = 14), anemia (n = 10), and urinary tract infection (n = 8). The median total duration of urticaria was 47 weeks (min:8, max:284). The duration of urticaria was longer in patients with atopy (p < 0.05), and the group that went into remission with standard-dose antihistamine was the group with highest eosinophil count (p = 0.022). In most children with CU, the underlying cause/disease cannot be determined. In our study, treatable triggers were found in some of the patients. Therefore, it is appropriate for each patient to be evaluated with selected laboratory tests after detailed history and physical examination.

Immunological Targets of Biologic Drugs in Allergic Skin Diseases in Children

Atopic dermatitis and urticaria are two invalidating skin disorders that are very common in children. Recent advances in the understanding of their specific intracellular molecular pathways have permitted the development of precise biological molecules, targeting inflammatory mediators and arresting the pathogenetic pathways of skin diseases. Many biologics with promising results have been studied, although few are currently approved in children. In this review, we aim to provide the latest evidence about the use, indications, efficacy and safety of biologic therapies to treat atopic dermatitis and chronic urticaria in children and adolescents.

Chronic urticaria in children - New insights from a large cohort

BACKGROUND

Chronic spontaneous urticaria is well-described in adults, but less so in children. The aim of this study is to describe the demographics, clinical characteristics, comorbidities, and outcomes of children with chronic, spontaneous urticaria.

METHODS

This retrospective study followed children up to 18 years old, diagnosed with chronic spontaneous urticaria, between the years 2002-2018, and treated in a tertiary referral allergy and clinical immunology center. Data including demographics, clinical characteristics, comorbidities, treatments, and outcomes were extracted from electronic medical records.

RESULTS

Records of 380 children coded to have chronic urticaria were reviewed, of which 250 (65.8%) fulfilled the diagnostic criteria for chronic spontaneous urticaria. There were 136 females (54.4%). Mean age at diagnosis was 11.4 years, and 122 (48%) were adolescents. The average duration of chronic spontaneous urticaria was 12.25 ± 15.2 months. The urticaria in 208 children )83.2%) resolved within 24 months. Eighty-seven patients (34.8%) had at least one atopic disease. Atopic comorbidities included atopic dermatitis in 17.2%, allergic rhinitis in 16%, asthma in 13.2%, and food allergy in 3.2%. Eighteen patients (7.2%) had a concomitant autoimmune disease. Nine (3.6%) had thyroid disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Chronic spontaneous urticaria in children is a self-limited disease with favorable prognosis. Atopic diseases are more prevalent in children with chronic spontaneous urticaria than in the general pediatric population, increasing the possibility of a special subgroup of TH2-related chronic urticaria in children.

Serum IgE Predicts Difference of Population and Allergens in Allergic Diseases: Data from Weifang City, China

Background

Immunoglobulin E (IgE) is the most important promoter of allergic inflammation. However, there are few systematic studies on IgE in age range, genders, disease spectrum, and time regularity.

Aim

To screen the common allergens, allergen spectrum, and IgE difference between type 2 inflammatory allergic diseases and other allergic diseases in Weifang, China.

Methods

A retrospective study was performed by estimating patients' clinical data suffering from allergic diseases (urticaria, pollinosis, allergic rhinitis, atopic dermatitis, and bronchial asthma) between May 2019 and April 2020 using an allergen detection kit of Macro-Union Pharmaceutical.

Results

732 of the 1367 patients showed different antigen positive, and the positive rate was 53.5%. The most common allergens were dust mites, mixed fungi, Artemisia pollen, cat/dog dander, and cockroaches. There were 27.0% (369/1367) of the patients with single positive allergen-specific IgE (sIgE), 26.5% (363/1367) with multiple-positive IgE. The total immunoglobulin E (tIgE) levels varied with gender, age, and type of disease. There was a difference in the distribution of allergens between children and adults. A positive correlation between the serum-specific IgE and the corresponding local inhaled allergen density was observed.

Conclusions

In this study, we found that type 2 inflammatory allergic diseases have higher serum IgE and a higher probability of inhaled sIgE positive. According to age, gender, and condition, serological IgE detection of allergens provides new insight into the early diagnosis and prevention of allergic diseases.

Presence of positive skin prick tests to inhalant allergens and markers of T2 inflammation in subjects with chronic spontaneous urticaria (CSU): a systematic literature review

BACKGROUND

Current guidelines do not recommend performing aeroallergen skin prick testing (SPT) in chronic spontaneous urticaria (CSU).

OBJECTIVE

The objective of this review was to investigate the presence of aeroallergen sensitization and markers of T2 inflammation in subjects with CSU.

METHODS

Systematic literature reviews to identify all studies that evaluated the presence of T2 markers of allergic inflammation in CSU subjects were performed.

RESULTS

In 16 studies that assessed the prevalence of positive SPT to multiple aeroallergens in CSU, 38.5% of CSU subjects had positive SPT. In three controlled studies, 34.2% of CSU subjects had positive SPT to multiple aeroallergens, compared to 13.6% of controls (p = 0.047). In 18 studies that assessed the prevalence of house dust mite (HDM) positive SPT in CSU, 27.5% of CSU subjects had positive SPT. In three controlled studies, 27.5% of CSU subjects had positive SPT to HDM, compared to 2.1% of controls (p = 0.047). Overall, CSU subjects were 3.1 times more likely to be aeroallergen-sensitized (95% CI 1.7-5.8, p = 0.0002) and 6.1 times more likely to be HDM-sensitized (95% CI 3.7-9.9, p < 0.00001) than controls. Mean total serum IgE (tIgE) levels were 238 kU/L and median tIgE levels were 164 kU/L, which was greater than the upper 90th percentile of normal (< 137 kU/L). Compared to healthy controls, CSU subjects were 6.5 times more likely to have IgG autoantibody against FcεR1α (p = 0.001), 2.4 times more likely to have IgG anti-IgE antibody (p = 0.03) and 5 times more likely to have anti-thyroid peroxidase (anti-TPO) antibody (p = 0.02). When corticosteroids were withheld for ≥ 28 days, mean blood eosinophil percentage was elevated at 5.9% (normal < 4%), but other studies reporting absolute count found the mean was in the normal range, 239 × 10 6 / L (normal < 400 × 10 6 / L).

CONCLUSION

Increased aeroallergen sensitization, tIgE, autoantibodies and blood eosinophil percentage in the CSU subjects indicates the possible importance of T2 inflammation in the pathogenesis of CSU. Further studies may be warranted to determine if specific allergen avoidance, desensitization or improvement in the mucosal allergic inflammation present in asthma and/or rhinitis has any benefit in the management of CSU.

Assessment of thiol/disulphide homoeostasis and ischaemia-modified albumin and their relationship with disease severity in children with chronic urticaria

BACKGROUND

The pathogenesis chronic urticaria (CU) hasn't been fully understood. In recent years, it has been shown that thiol-disulphide homoeostasis, as an antioxidant system, plays important roles in both healthy individuals and various diseases. In different ischaemia-reperfusion states, high oxidative stress causes ischaemia-modified albumin (IMA) generation.

AIM

To investigate thiol/disulphide balance and IMA level in children with CU and their association with disease severity.

METHODS

Thirty children with CU and 20 healthy children as controls, aged 1-18 years, were included in this cross-sectional study. In all subjects, total thiol, native thiol, disulphide levels and IMA levels were measured in plasma by spectrophotometry. Disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated. The disease severity was rated by Urticaria Activity Score (UAS).

RESULTS

In the children with CU, the levels of native thiol (375.56 ± 56.22 μmol/L) and total thiol (415.69 ± 54.75 μmol/L) were significantly lower than the control group (475.20 ± 71.87 and 511.20 ± 73.73 μmol/L, respectively) (p = 0.000, p = 0.000). The ratio of native/total thiol * 100 was lower in patients than the control group (p = 0.002). IMA was significantly higher in the patient group than control group (p = 0.000). No significant correlation was found between UAS and thiol/disulphide homoeostasis (p > 0.05). The disulphide levels, disulphide/native thiol and disulphide/total thiol levels were found to be higher in patients with positive family history for autoimmune disorders than those without (p < 0.05).

CONCLUSION

In children with CU, impaired thiol/disulphide homoeostasis and increased IMA suggest that oxidative stress may play role in the disease pathogenesis.

Can allergy patch tests with food additives help to diagnose the cause in childhood chronic spontaneous urticaria?

INTRODUCTION

Chronic spontaneous urticaria (CSU) is characterized by the onset of symptoms which are not induced by specific triggers, but are rather spontaneous. A considerable number of patients report that foods or food additives might be responsible for their chronic urticaria.

AIM

To determine the prevalence of sensitization to food additives in children with CSU using atopy patch tests (ATP).

MATERIAL AND METHODS

Atopy patch tests for 23 different food additives were applied to 120 children with CSU and 61 healthy controls.

RESULTS

Seventeen (14.1%) children with CSU were sensitized with food additives. None of the control group had positive APT. Azorubine and Cochineal red were the food additives detected with the highest sensitization rates (5.8% (n = 7) and 6.7% (n = 8), respectively).

CONCLUSIONS

There can be an association between food additives and CSU. APT tests may be a helpful tool in the assessment and management of CSU so that easier to follow diets and effective treatments can be offered to families.

Management of chronic urticaria in children: a clinical guideline

The aim of this guidance is to provide recommendations to clinicians and other interested parties on chronic urticaria in children. The Italian Society for Pediatrics (SIP), the Italian Society for Allergy and Immunology (SIAIP), the Italian Society for Pediatric dermatology (SIDerP) convened a multidisciplinary panel that prepared clinical guidelines for diagnosis and management of chronic urticaria in childhood. Key questions on epidemiology, natural history, diagnosis, and management were developed. The literature was systematically searched and evaluated, recommendations were rated and algorithms for diagnosis and treatment were developed. The recommendations focus on identification of diseases and comorbidities, strategies to recognize triggering factors, improvement of treatment by individualized care.

Urticaria in children and adolescents: An updated review of the pathogenesis and management

The present survey represents the latest data on diagnosis and management of childhood urticaria. It has been observed that urticaria occurs less often in children than adults, with symptoms rarely lasting for over 6 weeks. Triggers or aggravating factors can be found only in 21%-55% of cases. Finding autoantibodies in children does not impact a disease prognosis, unlike in adult patients, where the presence of autoantibodies is associated with a more prolonged run of the disease, a more severe prognosis and more intensive treatment methods. The incidence of food allergy equals to 8%-10% of cases. The incidence of Helicobacter Pylori infection in children is lower than that in adults and comes to 10%-18%. Medical experts recommend using the same treatment schemes for adults and children. This survey describes different urticaria management patterns suggested by experts from Europe, America, and Russia in their recent guidelines. It has been noted that unlike the guidelines from 2014, the 2018 clinical practice guidelines for the diagnosis and management of urticarial once again suggest a four-step treatment scheme with assigning omalizumab for Step 3 and cyclosporine A for Step 4 in the event of low therapeutic efficacy of the previous step or its impossibility. Leukotriene antagonists (LTRAs) are currently removed from basic management to alternative programs.

Chronic urticaria and drug hypersensitivity in children

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

Evaluating Comorbidities, Natural History, and Predictors of Early Resolution in a Cohort of Children With Chronic Urticaria

Importance

Chronic urticaria (CU) affects 0.1% to 0.3% of children. Most cases have no identifiable trigger and are classified as chronic spontaneous urticaria (CSU). At least half of patients with CSU may have an autoimmune etiology that can be determined in vitro using the basophil activation test (BAT). While 30% to 55% of CU cases resolve spontaneously within 5 years in adults, the natural history and predictors of resolution in children are not known.

Objective

To assess the comorbidities, natural history of CU, and its subtypes in children and identify predictors of resolution.

Design, Setting, and Participants

We followed a pediatric cohort with chronic urticaria that presented with hives lasting at least 6 weeks between 2013 and 2015 at a single tertiary care referral center.

Exposures

Data were collected on disease activity, comorbidities, physical triggers, BAT results, complete blood cell count, C-reactive protein levels, thyroid-stimulating hormone levels, and thyroid peroxidase antibodies.

Main Outcomes and Measures

We assessed the rate of resolution (defined as absence of hives for at least 1 year with no treatment) and the association with clinical and laboratory markers.

Results

The cohort comprised 139 children younger than 18 years old. Thirty-one patients (20%) had inducible urticaria, most commonly cold induced. Six children had autoimmune comorbidity, such as thyroiditis and type 1 diabetes. Autoimmune disorders (24 patients [17%]) and CU (17 patients [12%]) were common in family members. Positive BAT results (CD63 levels > 1.8%) were found in 58% of patients. Patients with positive BAT results (CD63 level >1.8%) were twice as likely to resolve after 1 year compared with negative BAT results (hazard ratio [HR], 2.33; 95% CI, 1.08-5.05). In contrast, presence of basophils decreased the likelihood of resolution (HR, 0.40; 95% CI, 0.20-0.99). No correlation with age was found. Chronic urticaria resolved in 43 patients, with a rate of resolution of 10.3% per year. Levels of CD63 higher than 1.8% and absence of basophils were associated with earlier disease resolution.

Conclusions and Relevance

Resolution rate in children with CU is low. The presence of certain biomarkers (positive BAT result and basophil count) may help to predict the likelihood of resolution.

Autoimmune comorbidity in chronic spontaneous urticaria: A systematic review

BACKGROUND AND OBJECTIVE

Numerous autoimmune diseases (AIDs) have been linked to chronic spontaneous urticaria (CSU). Here, we provide the first extensive and comprehensive evaluation of the prevalence of AIDs in patients with CSU and vice versa.

METHODS

A Pubmed and Google Scholar search was performed to identify studies reporting the prevalence of various AIDs in CSU and vice versa published before April 2017.

RESULTS

The prevalence of individual AIDs in CSU is increased (≥1% in most studies vs ≤1% in the general population). AIDs with relatively high prevalence in the general population are also quite common in CSU patients, whereas those with low prevalence remain a rare finding in CSU. The rates of comorbidity in most studies were ≥1% for insulin-dependent diabetes mellitus, rheumatoid arthritis (RA), psoriasis and celiac disease (CD), ≥2% for Graves' disease, ≥3% for vitiligo, and ≥5% for pernicious anemia and Hashimoto's thyroiditis. Organ-specific AIDs are more prevalent in CSU than systemic (multiorgan or non organ-specific) AIDs. >2% of CSU patients have autoimmune polyglandular syndromes encompassing autoimmune thyroid disease (ATD) and vitiligo or pernicious anemia. Antithyroid and antinuclear antibodies are the most prevalent AID-associated autoantibodies in CSU. >15% of CSU patients have a positive family history for AIDs. The prevalence of urticarial rash in AID patients is >1% in most studies. This rash is more prevalent in eosinophilic granulomatosis with polyangiitis, ATD, systemic lupus erythematosus, RA and CD.

CONCLUSIONS

CSU patients have an increased risk of AIDs, especially adult female patients and those with a positive family history and a genetic predisposition for AIDs, who should be screened for signs and symptoms of AIDs.

Clinical features of adolescents with chronic idiopathic or spontaneous urticaria: Review of omalizumab clinical trials

BACKGROUND

Adults and adolescents were included in 3 phase 3 omalizumab trials in chronic idiopathic urticaria (CIU): ASTERIA I, ASTERIA II, and GLACIAL.

OBJECTIVE

To describe the baseline clinical profile of adolescent patients with CIU enrolled in the omalizumab trials to add to the limited literature available on CIU in this population.

METHODS

Data for patient demographics, baseline clinical disease characteristics, medical history, and previous CIU medication information (not efficacy assessments) from phase 3 omalizumab trials were pooled and descriptive statistical analyses performed for adolescent (12 to <18 years old) and adult (≥18 years old) subgroups. Inferential analysis was inappropriate, partly because of small sample size in the adolescent subgroup.

RESULTS

The pooled population of 975 patients with CIU included 39 adolescents (4.0%). Demographics of adolescents and adults with CIU were similar, but compared with adults, fewer adolescents had positive Chronic Urticaria Index test results. Baseline clinical disease characteristics were also similar between the subgroups, with the number of previous CIU medications slightly lower in adolescents compared with adults. Medical history and existing conditions in adolescents tended to be more allergy than cardiovascular related, and fewer experienced angioedema compared with adults.

CONCLUSION

Pooled data indicate differences in baseline demographic and clinical characteristics between adult and adolescent patient subgroups. This finding helps augment our understanding of the clinical profile of CIU in adolescents, but larger-scale studies in this population are warranted.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT01287117 (ASTERIA I), NCT01292473 (ASTERIA II), and NCT01264939 (GLACIAL).

Urticaria in children: pathogenetic mechanisms and the possibilities of modern therapy

The review collected the latest literature data on urticaria - one of the most frequent skin diseases in children, accompanied by the appearance of blisters. It is notorious that histamine-liberation lies in the basis of the disease pathogenesis, regardless of the cause provoking an exacerbation. Precisely this explains the unified principle of therapy for all variants of urticaria -the administration of non-sedating antihistamines in the first line. Urticaria is classified for acute and chronic based on the duration of the course (up to 6 weeks or more). Experts do not recommend that physicians carry out any special diagnostic measures in the acute form of the disease, paying the utmost attention to the administration of effective treatment. the review describes the causes of disease exacerbation, the pathogenesis and the clinic of urticaria. Attention is paid to various options for managing patients with urticaria, published in the latest expert recommendations in Europe, America and Russia.

High-dose anti-histamine use and risk factors in children with urticaria

AIM

The drugs of choice in the treatment of urticaria in children are H1-antihistamines. The aim of the study was to evaluate children with urticaria and define risk factors for requirement of high-dose H1-antihistamines in children with urticaria.

MATERIAL AND METHODS

The medical data of children who were diagnosed as having urticaria admitted to our outpatient clinic between January 2014 and January 2016 were searched. The medical histories, concomitant atopic diseases, parental atopy histories, medications, treatment responses, blood eosinophil and basophil counts, and serum total IgE levels were recorded. In addition, the urticaria activity score for seven days, autoimmune antibody tests, and skin prick test results were evaluated in children with chronic urticaria.

RESULTS

The numbers of the children with acute and chronic urticaria were 138 and 92, respectively. The age of the children with chronic urticaria was higher than that of those with acute urticaria (p<0.0001). There was no difference between the two groups in terms of blood eosinophil and basophil counts, and serum total IgE levels (p>0.05). There was a negative correlation between blood eosinophil count and the UAS7 score in children with chronic urticaria (r=-0.276, p=0.011). Chronic urticaria and requirement of high dose H1-antihistamines were significant in children aged ≥10 years (p<0.001, p=0.015). High UAS7 score (OR: 1.09; CI 95%: [1.03-1.15]) and basopenia (OR: 6.77; CI 95%: [2.01-22.75]) were associated with the requirement of high-dose H1-AH in children with chronic urticaria.

CONCLUSION

The requirement of high-dose H1-antihistamines was higher with children's increasing age. Disease severity and basopenia were risk factors for the requirement of high-dose H1-antihistamines.

The predictive factors for remission of chronic spontaneous urticaria in childhood: Outcome from a prospective study

BACKGROUND

There are few studies in children on the natural course of chronic spontaneous urticaria (CSU) because of its relative infrequency in childhood.

OBJECTIVE

To estimate the rate of remission and evaluate the prognostic factors in children with CSU.

METHOD

A total of 52 children with CSU were prospectively followed over a period of three years.

RESULTS

The remission rates at 12 months and 36 months were 32.7% and 48.1%. The mean duration of disease at the first visit in the non-remission group was higher than in the remission group at the end of the study (P=0.016). The remission rate of the patients who had been treated by standard dose antihistamine was higher than that of the patients who had been treated with the high-dose antihistamine and combination medications (P=0.004, P<0.001). The treatment steps were independent prognostic factors for remission by logistic regression analysis.

CONCLUSION

Our study indicates that urticaria controlled by a standard dose of antihistamine can predict a good prognosis independently from disease duration at first visit.

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.

Oxidative Stress in Children with Chronic Spontaneous Urticaria

The pathogenesis of chronic spontaneous urticaria (CSU) has not been fully understood; nevertheless, significant progress has been achieved in recent years. The aim of this study was to investigate the possible role of reactive oxygen species (ROS) in the pathogenesis of CSU. Sixty-two children with CSU and 41 healthy control subjects were enrolled in the study. An extensive evaluation of demographic and clinical features was done, and serum oxidative stress was evaluated by plasma total oxidant status (TOS) and total antioxidant status (TAS) measurements. The median value of plasma TOS was found to be 10.49 μmol H₂O₂ equiv./L (interquartile range, 7.29–17.65) in CSU patients and 7.68 μmol H₂O₂ equiv./L (5.95–10.39) in the control group. The difference between the groups was statistically significant (p = 0.003). Likewise, the median plasma TAS level in the CSU group was decreased significantly compared to that of the control group (2.64 [2.30–2.74] versus 2.76 [2.65–2.86] mmol Trolox equiv./L, resp., p = 0,001). Our results indicated that plasma oxidative stress is increased in children with CSU when compared to healthy subjects, and plasma oxidative stress markers are positively correlated with disease activity.

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.

A stepwise approach in the management of chronic spontaneous urticaria in children

Background

There is limited literature in the management of chronic urticaria in children. Treatment algorithms are generally extrapolated from adult studies.

Objective

Utility of a weight and age-based algorithm for antihistamines in management of chronic spontaneous urticaria (CSU) in childhood. To document associated factors that predict for step of control of CSU and time taken to attain control of symptoms in children.

Methods

A workgroup comprising of allergists, nurses, and pharmacists convened to develop a stepwise treatment algorithm in management of children with CSU. Sequential patients presenting to the paediatric allergy service with CSU were included in this observational, prospective study.

Results

Ninety-eight patients were recruited from September 2012 to September 2013. Majority were male, Chinese with median age 4 years 7 months. A third of patients with CSU had a family history of acute urticaria. Ten point two percent had previously resolved CSU, 25.5% had associated angioedema, and 53.1% had a history of atopy. A total of 96.9% of patients achieved control of symptoms, of which 91.8% achieved control with cetirizine. Fifty percent of all the patients were controlled on step 2 or higher. Forty-seven point eight percent of those on step 2 or higher were between 2 to 6 years of age compared to 32.6% and 19.6% who were 6 years and older and lesser than 2 years of age respectively. Eighty percent of those with previously resolved CSU required an increase to step 2 and above to achieve chronic urticaria control.

Conclusion

We propose a weight- and age-based titration algorithm for different antihistamines for CSU in children using a stepwise approach to achieve control. This algorithm may improve the management and safety profile for paediatric CSU patients and allow for review in a more systematic manner for physicians dealing with CSU in children.

Approaches to the diagnosis and management of chronic urticaria in children

Most guidelines for chronic urticaria (CU) in infants and children are based on limited pediatric evidence. Current evidence used to guide treatment in children is extrapolated from data focusing on older age groups. CU in children is a different and complex condition than that in adults. Furthermore, there is little published information regarding urticaria in Korean children. The aim of the present article is to review recent research on chronic childhood urticaria and improve the current understanding of its pathogenesis and management. The classification and definition of urticaria in adults also applies to children. CU is defined as a daily occurrence of spontaneous wheals, angioedema, or both for >6 weeks. The precise pathophysiology of CU is unknown and the rates of successful identification of a cause in children with CU vary from 20%-50%. There is no established laboratory test to evaluate the presence of urticaria. The natural course of childhood CU is undetermined, with limited reports discussing long-term outcomes. Second-generation H1 antihistamines are the cornerstone of management, while limited therapeutic drugs are available for adults.

Anaphylaxis and urticaria

Anaphylaxis and urticaria are common presenting allergic complaints. Affecting up to 2% of the population, anaphylaxis is a serious, life-threatening allergic reaction. Although not life-threatening, urticaria is a rash of transient, erythematous, pruritic wheals that can be bothersome and affects up to 25% of the population. All cases of anaphylaxis warrant thorough clinical evaluation by the allergist-immunologist, although most cases of urticaria are self-limited and do not require specialist referral. This article offers an overview of our current knowledge on the epidemiology, pathogenesis, triggers, diagnosis, and treatment of anaphylaxis and urticaria.

The role of focal infections in the pathogenesis of psoriasis and chronic urticaria

INTRODUCTION

The Focal Infection Theory, originally presented at the beginning of the 20(th) century, postulates that systemic diseases can be caused by microorganisms that arise from the focus of infection. Foci of infections have been described as sinuses, adenoids, tonsils, teeth, genitourinary tract, gall bladder and kidneys. A focus of infection is defined as the area that can occur in any part of the body, contains a pathogen (microorganism) and is usually asymptomatic. There are discordant opinions about the role of focal infections in the pathogenesis of psoriasis and urticaria.

AIM

To establish whether there is a higher incidence of focal infections in patients with chronic urticaria and psoriasis.

MATERIAL AND METHODS

We retrospectively reviewed 129 patients with a history of psoriasis and chronic urticaria: 58 women and 71 men treated in the Department of Dermatology of the Jagiellonian University Medical College in Krakow.

RESULTS

In the analyzed group, 11 patients had a dental consultation, 58 - laryngological consultation and 29 women had a gynecological consultation. The most common examples of focal infection were tonsillitis, upper respiratory tract infections, sinusitis, dental caries and genitourinary tract infections. Aggravating factors were similar to previously described.

CONCLUSIONS

A high incidence of focal infections in patients with psoriasis and urticaria suggests that infections may play a significant role in the pathogenesis of these skin disorders. Treatment of infection foci may play the key role in the remission of skin changes.

Evidence-based evaluation and management of chronic urticaria in children

Urticaria affects nearly 25% of the population at some time in their lives. In a subset of children, urticaria will develop into a chronic condition that can greatly affect quality of life. Although numerous causes and triggers are proposed for chronic urticaria (CU) in children, ranging from infections, allergens, and medications to physical factors and autoimmune disease, the exact etiology is not always identifiable. Accordingly, a large subset of cases are designated "chronic idiopathic urticaria." Because of the clinical complexities of CU, as well as the confusing literature on this topic, we have developed a conceptual framework based on the cumulative evidence to assist with the categorization, clinical evaluation, and treatment of CU in children.

Chronic urticaria: etiology and natural course in children

BACKGROUND

Chronic spontaneous urticaria (CSU) in childhood is infrequent, and information about the disease in children is limited. We attempted to investigate its etiologic factors, natural course, and predictors of prognosis.

METHODS

All children aged ≤ 18 years followed for CSU during an 8-year period were analyzed retrospectively, and the final outcomes were queried via a telephone interview.

RESULTS

One hundred patients (male/female ratio 1.27) with a median age of 9.2 years (range 0.7-17.2) at symptoms onset were evaluated. The median follow-up was 2.5 years (range 0.2-18.1). An autologous serum skin test was positive in 46.7% of the subjects (n = 45), with a female predominance (71.4%) (p = 0.023). In 13.8% of the children, ANA titers were over 1/100. Food allergy (n = 1), thyroid autoantibodies (n = 3), possible collagen disease (n = 1), and drug usage (deferoxamine) (n = 1) were found to be associated factors. Infections could not be confirmed as the cause of CSU. Recovery was seen in 16.5, 38.8, and 50.0% of the children after 12, 36, and 60 months, respectively. Though in multivariate analysis none of the factors, including age, gender, autologous serum skin test positivity, the presence of angioedema, or other allergic diseases, appeared to predict the prognosis, in univariate analysis being female and being older than 10 years of age predicted an unfavorable prognosis.

CONCLUSION

The etiology of CSU in children is mainly related to an autoreactive background, as in adults. CSU has a favorable prognosis, and resolution is seen in half of the children within 5 years. Girls older than 10 years may have an unfavorable prognosis.

Urticaria and thyroid autoimmunity

BACKGROUND

Chronic urticaria is a common clinical condition whose etiology, in about 75% of cases, is unknown and is therefore called chronic idiopathic urticaria (CIU). A link between CIU and autoimmune thyroid diseases was proposed several decades ago. Here we review this topic.

SUMMARY

Several studies have been performed to determine if and to what degree there is an association between CIU and autoimmune thyroid diseases, particularly autoimmune thyroiditis. Many of these studies were not well controlled, however. Approximately one-fourth of CIU patients have serological evidence of thyroid autoimmunity, suggesting that these two disorders are associated. The mechanisms for the apparent association between CIU and serological evidence of thyroid autoimmunity are not clear. There are no data regarding the correlations between CIU and histological features of autoimmune thyroiditis or hypothyroidism. Despite this, there are anecdotal reports regarding L-thyroxine administration in patients with CIU.

CONCLUSIONS

Screening for thyroid autoimmunity is probably useful in patients with CIU. More solid evidence, based on still lacking well-conducted controlled studies, is desirable to determine if there is a therapeutic role for L-thyroxine treatment in ameliorating the skin manifestations of urticaria.

Chronic spontaneous urticaria in children: itching for insight

While there is increasing information about the pathogenesis and treatment of chronic spontaneous urticaria (csU) in adults, there is little published information about csU in children. Consequently, most of the recommendations contained in current guidelines for the prevention and treatment of csU in infants and children is based on extrapolation of data obtained in adults. To rectify this, this review points out critical gaps in our knowledge and suggests strategies which may help us to improve our understanding of this condition. How common is csU in children? What do we know about its clinical presentation and the presence of useful biomarkers? What are its common underlying causes? What is the course of csU in children? How does csU affect the everyday life of children? What treatment options are available for children? To answer these questions, two separate types of information are required. The first is information about the prevalence of the condition in the community at large and how csU affects the everyday life of both the child-patient and the parent or carer. Because most csU cases in infants and children do not come to specialists but are treated by general practitioners or by parents using over-the-counter medications, these questions may be answered only by general population surveys or schools programmes. The second is clinical information including family history and disease presentation, the presence of biomarkers and comorbidities, objective measures of severity, frequency and duration of exacerbations, the response to therapy and the time to remission. Targeted questionnaires need to be developed and validated for these investigations. This has already begun in Germany with the establishment of the CU-KID Netzwerk (Email address: cu-kid@charite.de), the aim of which is to identify clinical centres and colleagues who treat children with urticaria and to initiate the information gathering described above.