Effects of Diet and Oxidative Stress on Disease Severity and Response to Omalizumab in Chronic Spontaneous Urticaria

February 24, 2026 updated by: Emine Ecem Hakkoymaz, Istanbul Training and Research Hospital

Investigation of the Effects of Diet and Oxidative Stress on Disease Severity and Response to Omalizumab Treatment in Patients With Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is an immune-mediated skin disorder characterized by pruritic wheals and/or angioedema. This study aims to evaluate the relationship between diet-derived antioxidant capacity and oxidative stress with CSU presence, disease activity, and response to omalizumab. Adults with active CSU and age/BMI-matched healthy controls will provide non-consecutive 3-day dietary records (two weekdays and one weekend day). Dietary antioxidant capacity will be calculated using ORAC metrics via BeBiS software. Oxidative stress biomarkers (total oxidant status, total antioxidant status, oxidative stress index, malondialdehyde, and advanced oxidation protein products) will be measured from venous blood samples. CSU disease activity will be assessed using UAS7 and UCT, along with an urticaria quality of life questionnaire. In CSU patients who receive omalizumab as clinically indicated, assessments will be repeated after 3 months to evaluate treatment response and associated changes in diet and oxidative stress markers.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

This is an observational, case-control study including 58 adults (18-65 years) with active chronic spontaneous urticaria recruited from a dermatology outpatient clinic and 58 age- and BMI-matched healthy volunteers. Demographic/clinical data and comorbidities will be recorded. Dietary intake will be captured using three non-consecutive 24-hour food consumption records (two weekdays, one weekend day). Food portions will be estimated using a standardized food photo catalogue and analyzed with BeBiS 9.0 to compute macro/micronutrients, glycemic index/load, and dietary antioxidant capacity using ORAC. Venous blood will be used to measure total oxidant status (TOS/TOK), total antioxidant status (TAS/TAK), advanced oxidation protein products (AOPP), and malondialdehyde (MDA), and to calculate oxidative stress index (OSI). In CSU patients, disease activity will be evaluated using UAS7 and the Urticaria Control Test (UCT), as well as an urticaria quality of life questionnaire. CSU patients with a clinical indication for omalizumab will be re-evaluated after 3 months, repeating dietary records, biomarker measurements, and clinical scores to assess treatment response.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
116

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
      • Istanbul, Turkey (Türkiye), 34098
        • Istanbul Training and Research Hospital, Dermatology and Venereology Clinic Cerrahpaşa Mh. Org. Abdurrahman Nafiz Gürman Cd. No:24, 34098 Fatih, Istanbul, Turkey

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Adults with active CSU and age/BMI-matched healthy volunteers

Description

Inclusion Criteria:

  • Age 18-65 years
  • CSU group: diagnosis of chronic spontaneous urticaria, active CSU, and written informed consent
  • Control group: healthy volunteers with similar characteristics (age/BMI-matched)

Exclusion Criteria:

  • Additional dermatologic, metabolic, endocrinologic, systemic inflammatory disease; malignancy (diagnosis or suspicion)
  • Use within last 3 months of anti-inflammatory drugs or drugs that may affect serum glucose/lipids
  • Special diet/nutrition status; antioxidant supplement use
  • Smoking or alcohol use
  • Pregnant or breastfeeding

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Cohort 1: Chronic Spontaneous Urticaria (CSU) Patients
58 adults with active CSU
Cohort 2: Healthy Controls
58 healthy volunteers matched by age and BMI

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Disease activity scores (UAS7, UCT) and urticaria quality of life questionnaire (CU-Q2oL)
Time Frame: Baseline

Disease activity and control will be assessed in CSU patients only using the Urticaria Activity Score over 7 days (UAS7) and Urticaria Control Test (UCT).

Quality of life will be assessed in CSU patients only using an urticaria quality of life questionnaire (CU-Q2oL)
Baseline
Oxidative stress biomarkers (TOK, TAK, AOPP, MDA; OSI calculated)
Time Frame: Baseline
From routine venous blood samples, Total Oxidant Capacity (TOK), Total Antioxidant Capacity (TAK), Advanced Oxidation Protein Products (AOPP), and Malondialdehyde (MDA) will be measured; Oxidative Stress Index (OSI) will be calculated as the TOK/TAK ratio.
Baseline
Dietary intake / dietary antioxidant capacity based on 3-day dietary record
Time Frame: Baseline
Dietary intake will be captured using three non-consecutive 24-hour dietary records (two weekdays, one weekend day). Dietary antioxidant capacity will be calculated using Oxygen Radical Absorbance Capacity (ORAC) with BeBiS 9.0 (Nutrition Information System).
Baseline

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in urticaria disease activity score (UAS7: Urticaria Activity Score over 7 days), urticaria control (UCT: Urticaria Control Test) and urticaria-related quality of life questionnaire score (CU-Q2oL)
Time Frame: Baseline to 3 months (after initiation of omalizumab)
All participants in the chronic spontaneous urticaria (CSU) patient group will initiate omalizumab (standard-of-care) and change in UAS7, UCT, CU-Q2oL will be reassessed after 3 months following omalizumab treatment
Baseline to 3 months (after initiation of omalizumab)
Change in oxidative stress biomarkers in venous blood (TOK, TAK, AOPP, MDA, OSI)
Time Frame: Baseline to 3 months after initiation of omalizumab
Change in Total Oxidant Capacity (TOK), Total Antioxidant Capacity (TAK), Advanced Oxidation Protein Products (AOPP), Malondialdehyde (MDA) and calculated Oxidative Stress Index (OSI) in chronic spontaneous urticaria (CSU) patient group from baseline to Month 3 after initiate omalizumab
Baseline to 3 months after initiation of omalizumab

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Associations between dietary variables, oxidative stress biomarkers, and clinical outcomes in CSU
Time Frame: Baseline (and Baseline to 3 months after omalizumab in CSU patients)
Statistical comparisons and correlation/association analyses will evaluate relationships between dietary measures (including antioxidant capacity), oxidative stress biomarkers, and CSU clinical scores (UAS7, UCT, CU-Q2oL).
Baseline (and Baseline to 3 months after omalizumab in CSU patients)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Istanbul Training and Research Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 19, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 19, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 24, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SBU-IEAH-KAEK-20251205-294

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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