Chronic spontaneous urticaria (CSU) is a chronic inflammatory skin disease that can substantially impair quality of life in children and adolescents. Pharmacological treatment may not adequately control symptoms in all patients, increasing interest in dietary interventions. This randomized controlled trial aims to compare the effects of a Mediterranean diet and a low-histamine diet, in addition to standard medical treatment, on disease activity, disease control, and quality of life in pediatric patients aged 12-18 years with chronic spontaneous urticaria. Participants will be allocated to one of three groups: standard treatment alone, standard treatment plus a low-histamine diet, or standard treatment plus a Mediterranean diet. The dietary intervention will last four weeks, with follow-up through eight weeks.