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

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: Enrolling by invitation
• Conditions: Chronic Spontaneous Urticaria (CSU)

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: Observational
• Enrollment (Estimated): 116

Contacts and Locations

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

Eligibility Criteria

• 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

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
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

Outcome Measure	Measure Description	Time Frame
Disease activity scores (UAS7, UCT) and urticaria quality of life questionnaire (CU-Q2oL)	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)	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	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

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)	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)	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

Outcome Measure	Measure Description	Time Frame
Associations between dietary variables, oxidative stress biomarkers, and clinical outcomes in CSU	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

• Sponsor: Istanbul Training and Research Hospital

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2025
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: February 19, 2026
• First Submitted That Met QC Criteria: February 19, 2026
• First Posted (Actual): February 24, 2026

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: oxidative stress; omalizumab; MDA; Chronic spontaneous urticaria; OSI; UAS7; total antioxidant status; total oxidant status; AOPP; dietary antioxidant capacity; UCT; ORAC
• Additional Relevant MeSH Terms: Pathologic Processes; Chronic Disease; Disease Attributes; Immune System Diseases; Hypersensitivity, Immediate; Hypersensitivity; Skin Diseases; Urticaria; Skin Diseases, Vascular; Pathological Conditions, Signs and Symptoms; Skin and Connective Tissue Diseases; Chronic Urticaria
• Other Study ID 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