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NCT Number: NCT07431658

Effects of Diet and Oxidative Stress on Disease Severity and Response to Omalizumab in 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.

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Key information

Conditions

Chronic Spontaneous Urticaria (CSU) Chronic Disease Chronic Urticaria Disease Attributes Hypersensitivity Hypersensitivity, Immediate Immune System Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Skin Diseases Skin Diseases, Vascular Skin and Connective Tissue Diseases Urticaria

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

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

Istanbul, 34098, Turkey (Türkiye)

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Primary outcomes

  1. 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)

  2. 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.

  3. 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).

Secondary outcomes

  1. 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

  2. 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

Other outcomes

  1. 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).

Sponsors and collaborators

Lead sponsor

Istanbul Training and Research Hospital

Other Gov

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2026
Study completion
2027
First posted
Feb 24, 2026
Registry last updated
Feb 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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