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.