Mediterranean and Low-Histamine Diets for Pediatric Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is a chronic inflammatory disease characterized by recurrent pruritic skin lesions during childhood and has a significant negative impact on quality of life. Since its etiology is often unknown, treatment approaches generally focus on symptom control. However, pharmacological treatments do not always provide an adequate response, increasing the importance of complementary dietary approaches. In recent years, the Mediterranean diet, known for its anti-inflammatory properties, and the low-histamine diet, which restricts foods with a high histamine content, have emerged as promising options for the management of CSU symptoms. However, no controlled study has directly compared these two dietary approaches in the pediatric population.

This study is planned as a three-arm randomized controlled clinical trial aiming to compare the effects of Mediterranean and low-histamine dietary interventions on disease activity, disease control, and quality of life in children aged 12-18 years diagnosed with chronic spontaneous urticaria. The intervention period will last four weeks, and assessments will be performed at baseline and at the end of the fourth week. The study will use the Urticaria Activity Score over 7 days (UAS7), the Urticaria Control Test (UCT), quality of life questionnaires (Children's Dermatology Life Quality Index [CDLQI] and Dermatology Life Quality Index [DLQI]), and the Mediterranean Diet Quality Index for Children and Adolescents (KIDMED). Dietary patterns will be assessed using a Food Frequency Questionnaire (FFQ) at baseline and monitored during the intervention period through weekly 24-hour dietary recalls and Dietary Adherence Follow-up Forms. In addition, routinely obtained clinical laboratory parameters, including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), total immunoglobulin E (total IgE), thyroid function tests (TSH and fT4), thyroid autoantibodies (anti-TPO and anti-Tg), complete blood count, and 25-hydroxyvitamin D [25(OH)D] levels, will be evaluated at baseline.

This study is expected to fill an important gap in the current literature by demonstrating the effectiveness of dietary approaches in pediatric chronic spontaneous urticaria and to contribute to clinical practice.

Inclusion criteria

• Age 12-18 years. Confirmed diagnosis of Chronic Spontaneous Urticaria (CSU) according to international guidelines.

No recent use of systemic corticosteroids or immunosuppressive therapy (except short-term acute use).

Written informed consent provided by both the participant and a parent/legal guardian.

Exclusion criteria

• Presence of a neurodevelopmental disorder. Presence of any other known chronic disease. Presence of a disease requiring a special therapeutic diet. Presence of an acute infection. Presence of any food allergy. Recent use of systemic corticosteroids, biologic agents, immunosuppressive therapy, or high-dose antihistamines (except short-term acute use).