Impact of Chronic Spontaneous or Inducible Urticaria on Occupational Activity.

The impact of chronic urticaria on work has been scarcely reported, whereas its peak incidence is between the ages of 20 and 40. The aim of this study was to assess the occupational impact of chronic urticaria and its treatment, by combining objective and patient-reported data. A monocentric observational study was performed using questionnaires over a 1-year period from 2021 to 2022 in chronic urticaria patients who were in a period of professional activity and agreed to participate. Of the 88 patients included, 55.7% assessed the occupational impact of their chronic urticaria as significant, and even more severe when chronic urticaria was poorly controlled. Some 86% of patients had symptoms at work, in a third of cases aggravated by work. However, occupational physical factors were not associated with an aggravation of inducible chronic urticaria. A total of 20% reported treatment-related adverse effects affecting their work. Despite low absenteeism, presenteeism and reduced productivity were important (> 20%). Six patients (6.8%) had difficulties keeping their work. For 72.7% of the patients, the occupational physician was not informed. The occupational impact of chronic urticaria should be discussed during consultations, particularly when it is insufficiently controlled. The occupational physician should be informed in order to support patients' professional project.

A Case-Control Study Comparing the General Characteristics of Patients with Symptomatic Dermographism and Chronic Spontaneous Urticaria: Is Atopy a Risk Factor for Symptomatic Dermographism?

INTRODUCTION: Symptomatic dermographism (SDerm) is the most common chronic inducible urticaria (CIndU) subtype. There is still limited information in the literature about clinical features, triggering factors, and accompanying comorbidities of SDerm. The aim of this study was to compare the clinical features and laboratory data of patients with SDerm and chronic spontaneous urticaria (CSU). METHODS: The clinical features and laboratory data of patients with SDerm and CSU were compared retrospectively. The laboratory data and general characteristic features of the patients were obtained from the medical records. RESULTS: The study included a total of 361 patients (CSU: 220, SDerm: 141). The rates of asthma (odds ratio [OR]: 1.79, p = 0.036), allergic rhinitis (OR: 6.03, p < 0.001), and thyroid disease (OR: 1.78, p = 0.039) were higher in patients with SDerm. The disease duration (median 12 months, p < 0.001) and regular antihistamine use (OR: 0.31, p < 0.001) were lower in patients with SDerm. Total IgE level (median: 193, p < 0.001), thyroid antibody positivity (OR: 1.93, p = 0.039), and atopy (OR: 8.81, p < 0.001) were higher in patients with SDerm. Dermatophagoides pteronyssinus (OR: 17.72, p < 0.001), Dermatophagoides farinae (OR: 17.20, p < 0.001), grass pollen (OR: 2.50, p < 0.026), cat epithelium (OR: 3.68, p < 0.023), and cockroach (OR: 4.93, p < 0.009) allergen positivity rates were higher in patients with SDerm. CONCLUSION: Atopic diseases such as asthma and allergic rhinitis and the sensitization rate to aeroallergens seem to be higher in patients with SDerm than in patients with CSU. The results of this study should be supported by multicenter studies of patients from different geographical regions.

Comorbid Inducible Urticaria Is Linked to Non-Autoimmune Chronic Spontaneous Urticaria: CURE Insights.

BACKGROUND: Patients with chronic spontaneous urticaria (CSU) can have comorbid inducible urticaria (CIndU). How comorbid CIndU affects patients and their CSU is largely unclear. OBJECTIVE: To compare patients with CSU with and without comorbid CIndUs for differences in demographic features, clinical characteristics, and laboratory markers. METHODS: We analyzed 708 patients with CSU of our Urticaria Center of Reference and Excellence enrolled in CURE, the chronic urticaria registry. CURE data collected until October 2022 were used to compare patients with and without comorbid CIndU for their demographic characteristics, disease onset, activity, impact, and control, as well as concomitant allergic and autoimmune diseases and laboratory parameters associated with autoimmune CSU. RESULTS: Of 708 patients with CSU, 247 (35%) had comorbid CIndU. Compared with patients with standalone CSU, patients with CSU with comorbid CIndU were significantly younger, had earlier disease onset, longer disease duration, higher impact on quality of life, and a higher rate of concomitant allergic diseases. Moreover, patients with CSU with comorbid CIndU less often had features linked to autoimmune CSU such as angioedema, concomitant autoimmune diseases, eosinopenia, low levels of total IgE, and low total IgE combined with elevated anti-thyroid peroxidase IgG. CONCLUSIONS: Autoimmune CSU may be less common in patients with comorbid CIndU than without, and comorbid CIndU may point to autoallergic CSU.

Patients With Chronic Spontaneous Urticaria Who Have Wheals, Angioedema, or Both, Differ Demographically, Clinically, and in Response to Treatment-Results From CURE.

BACKGROUND: Patients with chronic spontaneous urticaria (CSU) have spontaneous wheals (W), angioedema (AE), or both, for longer than 6 weeks. Clinical differences between patients with standalone W, standalone AE, and W and AE (W+AE) remain incompletely understood. OBJECTIVE: To compare W, AE, and W+AE CSU patients regarding demographics, disease characteristics, comorbidities, disease burden, and treatment response. METHODS: Baseline data from 3,698 CSU patients in the ongoing, prospective, international, multicenter, observational Chronic Urticaria REgistry (CURE) were analyzed (data cut: September 2022). RESULTS: Across all CSU patients, 59%, 36%, and 5% had W+AE, W, and AE, respectively. The W+AE patients, compared with W and AE patients, showed the lowest male-to-female ratio (0.33), higher rates of concomitant psychiatric disease (17% vs 11% vs 6%, respectively), autoimmune disease (13% vs 7% vs 9%, respectively), and nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity (9% vs 5% vs 2%, respectively) and the highest disease impact. The W patients, compared with W+AE and AE patients, showed the lowest rates of concomitant hypertension (15% vs 21% vs 40%, respectively) and obesity (11% vs 16% vs 17%, respectively), the highest rate of concomitant inducible urticaria (24% vs 22% vs 6%, respectively), and shorter W duration. The AE patients, compared with W+AE and W patients, were older at disease onset, showed longer AE duration, and the best response to increased doses of H1-antihistamines (58% vs 24% vs 31%, respectively) and omalizumab (92% vs 67% vs 60%, respectively). CONCLUSIONS: Our findings provide a better understanding of CSU phenotypes and may guide patient care and research efforts that aim to link them to pathogenic drivers.

Exacerbation of Chronic Spontaneous Urticaria Following Coronavirus Disease 2019 (COVID-19) Vaccination in Omalizumab-Treated Patients.

BACKGROUND: The rapid development and rollout of vaccines against coronavirus disease 2019 (COVID-19) has led to more than half of the world's population being vaccinated to date. Real-world data have reported various adverse cutaneous reactions, including delayed-onset urticaria, which was highly ranked as a common manifestation across studies. However, the impact of these novel mRNA or viral vector COVID-19 vaccines on preexisting chronic spontaneous urticaria (CSU) remains largely unknown. OBJECTIVE: To investigate the impact of COVID-19 vaccination on the clinical status of patients with relatively stable CSU who are undergoing omalizumab treatment and to identify risk factors for exacerbation. METHODS: We conducted a questionnaire-based cross-sectional study in a tertiary hospital. Adult patients with relatively stable CSU under regular omalizumab treatments who had received at least one COVID-19 vaccination were included. RESULTS: There were 105 study subjects who received 230 COVID-19 vaccinations between March and December 2021. Fifteen patients (14.3%) experienced aggravation of urticaria at least once after COVID-19 vaccination. The demographics and clinical characteristics of the patients were comparable regardless of the exacerbation of CSU. However, case-level analysis revealed that the presence of urticaria (vs none) before vaccination (odds ratio [OR] = 4.99; 95% CI, 1.57-15.82) and the development of systemic reactogenicity (OR = 4.57; 95% CI, 1.62-12.90) were associated with a higher risk for exacerbation. CONCLUSIONS: The novel COVID-19 vaccination induced exacerbation in more than one-tenth of patients with well-controlled CSU. The establishment of a proper management strategy during COVID-19 vaccination is necessary for patients with CSU.

Chronic spontaneous urticaria and metabolic syndrome: a relationship conundrum.

Chronic spontaneous urticaria (CSU) and metabolic syndrome (MetS) are associated with low-grade inflammation. Despite intensive research and various hypothesis, there is lack of specific pathomechanisms of urticaria. Previous studies have suggested low-grade inflammation in obesity which may be linked to urticaria. However, there is limited literature on association of MetS and CSU. So, this study was conducted to evaluate the association of MetS and its components in patients with CSU. This was a hospital-based and cross-sectional cohort study in which 481 patients of CSU and 240 age- and gender-matched controls were recruited. MetS was defined using the revised National Cholesterol Education Program Adult Treatment Panel III. BMI, waist circumference, blood pressure, fasting blood sugar, plasma insulin, and lipid profile were measured after overnight fasting. Pearson's Chi-squared test was used to calculate significance. Logistic regression analysis was done to assess MetS as a predictor of CSU. All patients were started on antihistamines according to the severity of the disease. CSU patients comprised 220 men (45.7%) and 261 women (54.3%) with 97 patients (20.12%) qualifying criteria for metabolic syndrome compared with 73 (30.42%) controls without any significant difference (p = 0.177). CSU was significantly associated with a higher prevalence of central obesity (p = 0.003) but CSU patients with central obesity did not have a higher urticaria activity score (p = 0.727) or serum IgE levels (p = 0.359). In conclusion, our study found an increased association of central obesity with CSU that was not related to the severity of urticaria. This is of significance as obesity is the most prevalent and first component of MetS to be developed. There was no increase in the overall prevalence of MetS in patients with CSU. The increased association of obesity and urticaria in our study can be partially explained by the role of antihistamines in modulation of metabolic pathway and appetite. Future research into the same can give better insights and thus can aid in better management options in CSU patients.

Risk Factors of Quality-Of-Life and Sexual Function Impairment in Chronic Spontaneous Urticaria Patients: Cross-Sectional Study.

BACKGROUND: Chronic spontaneous urticaria (CSU) has been associated with poor quality of life and mood disturbances. However, factors associated with these dimensions have not been properly assessed. Moreover, there is a lack of studies regarding sexual dysfunction (SxD) and CSU. Therefore, the aims of this study were to assess quality of life associated factors and to evaluate the prevalence and potential impact of SxD in patients with CSU. METHOD: Cross-sectional study of patients suffering from CSU. Sociodemographic and disease activity variables, quality of life, sleep, SxD, anxiety, and depression were collected using validated questionnaires. RESULTS: Seventy-five patients were included, with a female-to-male ratio of 2.40. Female sex, worse disease control, and sexual dysfunction were associated with poor quality-of-life indexes (p < 0.001). SxD was detected in 52% of female and 63% of male patients. SxD was associated with poor disease control (p < 0.001). Female SxD, but not male, was associated with poorer quality of life (p = 0.02) and an increased risk for anxiety 85% and depression 90% (p < 0.05). CONCLUSIONS: Female patients and those with an inadequate control of CSU are in higher risk of having poorer quality of life. SxD seems to be frequent in patients with CSU. Moreover, female SxD seems to have a more profound impact on quality of life and mood disturbances when compared to males. Assessment of SxD in Urticaria Clinic might be of benefit to identify patients at a higher risk of poor quality of life.

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.

Risk of Atopic Disorders in Patients with Chronic Urticaria: A Systematic Review and Meta-Analysis.

BACKGROUND: Chronic urticaria (CU) has been associated with several systemic and autoimmune disorders. The association with atopic disorders is however controversial. The objective of this study was to perform a systematic review and meta-analysis to assess the association between CU and the atopic disorders: atopic dermatitis (AD), asthma, and allergic rhinoconjunctivitis (ARC). METHODS: Search hits from PubMed, Embase, Cochrane Library, and Web of Science were systematically reviewed. English papers from 2000 to present, containing original data of the association (prevalence, incidence, or risk) between CU and any atopic disorder(s), were included. Pooled point prevalence and OR with 95% confidence intervals were calculated with a random effects model. RESULTS: A total of 8,108 search hits were screened and reviewed. Thirty-eight studies met all inclusion criteria. The estimated pooled point prevalence of AD, asthma, and ARC in CU was 7% (5-11%, I2 = 99%), 12% (9-15%, I2 = 100%), and 22% (16-29%, I2 = 100%), respectively. Pooled ORs were estimated to 2.75 (2.05-3.68, I2 = 94%) for AD, 1.87 (1.01-3.45, I2 = 100%) for asthma, and 2.94 (1.84-4.68, I2 = 100%) for ARC. CONCLUSION: Pooled point prevalences of atopic disorders in CU were comparable to the general population. However, studies that compared prevalences with controls from the same population all found a significantly increased risk of atopic disorders in CU. Results should however be interpreted with caution as high heterogeneity was found in all analyses.

Clinical characteristics and treatment response of chronic spontaneous urticaria according to age: A single-center Korean study.

BACKGROUND: Little information exists regarding the incidence of chronic spontaneous urticaria (CSU) or differences in its characteristics according to age. OBJECTIVE: To evaluate the incidence, clinical characteristics and treatment response of CSU according to age. METHODS: The relevance of gender, age, history of allergic disease, pre-diagnosis duration, and treatment response were retrospectively evaluated in patients diagnosed with CSU at Pusan National University Hospital between 2011 and 2018. RESULTS: A total of 970 patients were included in the study, consisting of 198 children and 772 adults. The CSU incidence increased during the study period in children, but not in adults. CSU was more common in adults than in children and the peak age of occurrence was 20-59 years. Increased female incidence was noted in adults, whereas patient and family allergic history was frequently observed in children than in adults. The overall rate of improvement was remarkably higher in children than in adults (P < 0.01), with pre-diagnosis duration and treatment duration both shorter in children than in adults. (P = 0.001). The proportion of men was higher and treatment duration was shorter in adolescence than in the other age groups, whereas the treatment duration was shorter in patients greater or equal to 60 years than in adults under 60 years, and the step 1 treatment rate was higher. CONCLUSIONS: CSU incidence increased annually in children, but not in adults. The clinical characteristics and treatment response of CSU may differ depending on age and clinicians should be made aware of this fact.

Evaluation of the Reliability and Validity of the Persian Version of Urticaria Control Test (UCT).

The urticaria control test (UCT) is a patient-reported outcome measure (PROM) for chronic urticaria (CU) patients. As a Persian version of the UCT was not available, the present research aimed to develop such a version, to test its reliability and validity as well as to evaluate urticaria control among Persian-speaking patients. This research was conducted at the Urticaria Centre of Reference and Excellence (UCARE) of Ghaem Hospital, Mashhad, Iran. In a first step, a linguistically validated Persian version of the UCT was developed through a structured forward and backward translation process and subsequent cognitive debriefing interviews. In a second step, the Persian version of the UCT was completed by 100 well-characterized CU patients together with two anchor instruments, the Chronic Urticaria Quality of life Questionnaire (CU-Q2oL) and the urticaria activity score (UAS), to obtain information on its internal consistency reliability and convergent validity. The Persian version of the UCT was found to have acceptable internal consistency reliability with a Cronbach's alpha coefficient of 0.68. In addition, the results obtained with the Persian UCT correlated with the CU-Q2oL total score (-0.48, p<0.001) and the UAS (-0.404, p˂0.001), suggesting convergent validity. Virtually all patients had poorly controlled CU (UCT<12). A Persian version of the UCT is now available and may help to improve the assessment and monitoring of disease control in Persian-speaking CU patients and to optimize treatment decisions.

Psychological burden of COVID-19 on mild and moderate chronic spontaneous urticaria

Background: The impact of coronavirus disease 2019 (COVID-19) related mental health status on chronic spontaneous urticaria (CSU) has not been addressed before. Objective: The aim of this study was to evaluate the depression, anxiety and stress levels, and the fear of COVID-19 in patients with mild-to-moderate CSU and to determine their impact on urticaria activity during the pandemic. Methods: A total of 509 patients with mild-to-moderate CSU were prospectively evaluated with validated scales, the Depression Anxiety Stress Scale 21 (DASS-21) and the Fear of COVID-19 Scale (FCV-19S) during the lockdown period (LP) and the return to normal period (RTNP). CSU activity was determined with the urticaria activity score summed over 7 days (UAS7) and medication scores (MS). UAS7 and MS before the pandemic were retrospectively collected from medical records. Results: The median UAS7 and MS were both significantly higher in the LP than in the median of related scores during the prepandemic period (p < 0.0001) and the RTNP (p < 0.0001). The mean FCV-19S and DASS-21 scores were both significantly higher in the LP than in the RTNP (p < 0.0001). The FCV-19S and the DASS-21 anxiety and stress subscales were significantly higher in women. The UAS7s were positively correlated with the FCV-19S and depression, anxiety, and stress subscale scores. Conclusion: Fear of COVID-19, anxiety, depression, and stress during the COVID-19 pandemic, especially when strict isolation measures are taken, have a significant impact on mental health and urticaria activity in patients with mild-to-moderate CSU, even though they are not infected. Psychological support for patients with CSU seems to be important to control disease activity during the pandemic.

Association of PTPN22 single nucleotide polymorphisms with chronic spontaneous urticaria.

INTRODUCTION AND OBJECTIVES: Chronic spontaneous urticaria (CSU) is thought to be an autoimmune disease in a subpopulation of patients. Protein tyrosine phosphatase-22 (PTPN22) polymorphisms are considered to be one of the strongest contributing factors to autoimmune diseases. In this study, we aimed to investigate the potential association of several PTPN22 single nucleotide polymorphisms (SNPs) with CSU in an Iranian population. MATERIAL AND METHODS: A total of 93 CSU patients and 100 healthy individuals were included in this study. Five SNPs within the PTPN22 gene were analyzed using TaqMan genotyping assays. The frequency of alleles, genotypes, and haplotypes of PTPN22 SNPs (rs12760457, rs2476601, rs1310182, rs1217414, and rs33996649) was investigated. RESULTS: A significantly higher prevalence of the rs1310182 T allele was observed among patients compared with controls [OR = 1.75 (95% CI: 1.17-2.63); P = 0.007]. In addition, the rs1310182 CC genotype and TT genotype were 0.47 and 2.06 times more common in patients, respectively (P = 0.03). Moreover, haplotype analysis demonstrated that CGCGC, CGTGC, and TGCGC (P < 0.001) were significantly associated with CSU. No significant differences were observed between the patients and controls in the other analyzed PTPN22 SNPs. CONCLUSIONS: Polymorphisms of the PTPN22 gene are associated with an increased susceptibility to CSU in the studied Iranian population.

Peptic Ulcer Disease is Associated with Increased Risk of Chronic Urticaria Independent of Helicobacter pylori Infection: A Population-Based Cohort Study.

BACKGROUND: Some studies showed patients with chronic urticaria have a higher rate of peptic ulcer disease (PUD). Whether PUD is a risk factor for chronic urticaria is unclear. OBJECTIVE: The objective of this study was to evaluate the incidence of and risk factors for chronic urticaria in patients with PUD using the Taiwan National Health Insurance Research Database. METHODS: We conducted a retrospective nationwide cohort study of the period 2000-2012 and involving 11,901 patients with PUD who underwent Helicobacter pylori (HP) therapy (PUD + HP group) and an equal number of matched patients without HP infection (PUD - HP group). Furthermore, we enrolled 23,802 patients without PUD for comparison (non-PUD group). The Cox proportional hazards regression model was used to analyze chronic urticaria risk after adjusting for potential confounding factors. RESULTS: The mean ages of the three groups were around 50 years. Approximately 42.6% were female. Chronic urticaria incidences in the PUD + HP and PUD - HP groups were both significantly higher than that in the non-PUD group. The hazard ratios of chronic urticaria in the PUD + HP group and the PUD - HP group were 1.34 (95% confidence interval 1.09-1.64) and 1.45 (95% confidence interval 1.19-1.79), respectively. The risk difference became significant 2 years after patients with PUD had the HP infection tests and persisted till the end of follow-up. The risk increase was significant in patients with PUD who were female or aged 40-64 years. There was no difference in the risk comparison between PUD + HP and PUD - HP groups. CONCLUSIONS: Peptic ulcer disease, independent of HP infection, is associated with an increased chronic urticaria risk. Patients with PUD who were female or aged 40-64 years are more likely to have chronic urticaria.

The association of chronic spontaneous urticaria (CSU) with anxiety and depression: a nationwide cohort study.

Chronic spontaneous urticaria (CSU) is a dermatological disease associated with significant impairment of overall quality of life as well as psychological distress. Previous studies have demonstrated significant comorbidity between CSU and a wide range of mental illnesses. In this study we aimed to focus on the association between CSU and anxiety and depression, using an optimized matched controlled design. A nationwide matched control study was conducted using the Clalit Health Services (CHS) database. The study included 12,539 CSU patients and 60,510 age and sex matched controls. Three multiple logistic regression models were conducted to assess the association between CSU and anxiety and depression, while adjusting for age, sex, socioeconomic status (SES), diabetes, obesity, hypertension, and smoking status. A higher frequency of anxiety and depression was found in CSU patients compared to that in controls (anxiety frequency of 9.6% vs. 5.7%, p < 0.001; depression frequency of 11% vs 7.9%, p < 0.001, respectively) after adjustment for demographic and clinical factors. The association of CSU with anxiety was the strongest in the 18-29 age group, and in the high SES group, while the association of CSU with depression was the highest in the 50-69 age group, and in the low SES group. Chronic spontaneous urticaria is associated with anxiety and depression. In light of the clinical implications of a comorbid mental disorder, dermatologists should consider employing mental health screening procedures, especially for patients from specific risk groups.

Investigation of self-reported chronic urticaria among adults in grasslands of northern China.

The clinical epidemiological characteristics of chronic urticaria (CU) in different populations were not completely consistent, and the epidemiological characteristics of CU were very complex. At present, there were some patient-based studies on CU, but few natural population-based studied in the world.This study aimed to analysis the prevalence of self-reported CU among adults in grasslands of northern China and its closely related factors.A multistage and proportionately stratified random sampling with a field interviewer-administered survey study was performed together with skin prick tests (SPT) and measurements of the daily pollen count.A total of 3406 subjects completed the study. The prevalence of self-reported CU was 5.61% (n = 191), which was higher in women than that of men (6.91% vs 4.08%, X = 12.785, P < .001). Seasonal or seasonal aggravation CU accounted for 110 (57.59%) patients. Pollen dispersal season was basically consistent with the peak season of CU, but there was no significant difference in the positive rate of pollen SPT between CU with seasonal or seasonal aggravation symptom and CU with free of symptom (X = 0.425, P = .51), as well as between CU with seasonal or seasonal aggravation symptom and perennial CU (X = 0.439, P = .51). Eczema (odds ratio [OR] = 2.807, P < .001), chronic diarrhea (OR = 2.486, P < .01), food allergy history (OR = 1.890, P < .01), history of family allergy (OR = 1.800, P < .001), and conjunctivitis (OR = 1.749, P < .01) were closely related to CU.This investigation provided the factors closely related to CU, and provided certain ideas for further research on the etiology and prevention of CU.

A protocol for the development and internal validation of a model to predict clinical response to antihistamines in urticaria patients.

Chronic urticaria causes a significant limitation to quality of life. In the literature, various studies can be found that have reviewed several clinical and laboratory markers, but none of these variables alone is sufficient to predict the patient's prognosis. In this study, we present a protocol to develop a prognostic model that can predict the clinical response of urticaria patients to antihistamines. This is a protocol for a bidirectional cohort study. Urticaria data will be routinely collected from a population of patients over 18 years old. A full multivariable logistic regression model will be fitted, following five steps: 1) Selection of predictive variables for the model; 2) Evaluation of the quality of the collected data and control of lost data; 3) Data statistical management; 4) Strategies to select the variables to include at the end of the model; 5) Evaluation of the performance of the different possible models (predictive accuracy) and selection of the best model. The performance and internal validation of the model will be assessed. Some clinical and paraclinical variables will be measured for further exploration.