D2.364 - Omalizumab Use in Pediatric Chronic Urticaria, A Retrospective Study from a Tertiary Hospital

Urticaria is an inflammatory condition characterized by the occurrence of pruritic wheals, angioedema, or both. It is classified based on duration, with acute urticaria resolving quickly and chronic urticaria (CU) persisting for more than six weeks. CU can be further categorized based on its triggers: chronic inducible urticaria (CIndU), which occurs in response to specific stimuli, and chronic spontaneous urticaria (CSU), which arises without an identifiable cause. The primary aim of urticaria treatment is symptom elimination. The first-line treatment for CU in children is second-generation H1-antihistamines. In cases of refractory CU—where patients do not respond to H1-antihistamines or their up-dosing—omalizumab can be introduced as a second-line therapy. Omalizumab is a monoclonal antibody targeting IgE and is approved for the treatment of CSU in children older than 12 years.

The aim of this study is to determine the rate of children treated with omalizumab in the Outpatient Pediatric Allergy Department of a Tertiary Hospital.

This retrospective study examined children diagnosed with chronic urticaria over two years at the outpatient pediatric allergy department of a Tertiary Hospital. Patient records were reviewed, and relevant information—including laboratory findings, family history, demographic characteristics, and treatment response—was collected and analyzed.

Among a population of approximately 85 children diagnosed with CU, only 7 (8,2%) required treatment with omalizumab due to unresponsiveness to antihistamines and their up-dosing. All patients were girls above 12 years of age. Common laboratory findings among these patients included elevated eosinophil counts (1500 cells/µL) and high IgE levels (maximum 3950 IU/ml). Additionally, these patients exhibited increased levels of D-dimers (>2). Two of the seven patients experienced relapse after remission and required retreatment with omalizumab.

Chronic urticaria is an inflammatory condition that significantly affects children's quality of life. While most children respond well to antihistamines, a small subset requires additional treatment with omalizumab. Identifying common characteristics among children with refractory urticaria may help refine treatment strategies and improve patient outcomes.