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

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.