Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 25 3 2026 04 22 293 302 Abbas Khalili Department of Pediatrics, Shahid Sadoughi Hospital, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran AND Hematology and Oncology Research Center, Shahid Sadoughi Hospital, Shahid Sadoughi University of Medical Sciences, Yazd, Iran AND Children Growth Disorder Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Zahra Estakhri Department of Pediatrics, Shahid Sadoughi Hospital, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Ali Shams Department of Immunology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Yeganeh Lalehzari Department of Immunology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran 2025 08 12 2025 12 01 The responses of patients with chronic spontaneous urticaria (CSU) to regular therapeutic options vary. While these methods are effective for some patients, many do not respond successfully. Despite several studies conducted to identify immunologic and inflammatory biomarkers in patients that can predict response, our current knowledge is insufficient. This study aimed to identify biomarkers that may predict therapeutic response. The present interventional study evaluated 61 moderate-to-severe CSU patients aged 20 to 50 years who presented to our clinic from January 2024 to January 2025. Peripheral blood samples, serum, and plasma were collected to measure inflammatory and immunological variables, and were analyzed at a reference laboratory. Subsequently, patients were treated with cetirizine 10 mg every 12 hours and famotidine 40 mg every night. After 1month, urticarial severity was reassessed using the same questionnaire. Severity scores were compared between patients with elevated biomarkers and those with normal levels. Sixty-one patients with chronic spontaneous urticaria were enrolled; 77% female and 23% male. Forty-one patients experienced a good response to treatment, while 20 patients did not. The average (Urticaria Activity Score) UAS7 scores before and after treatment were 27.72 and 12.67, respectively. Among the serum biomarkers evaluated, only the neutrophil-to-lymphocyte ratio (NLR) and serum eosinophil count showed a significant relationship with treatment response. To conclude, a high eosinophil count and NLR may serve as predictors of a poor clinical response to antihistamine therapy. However, further clinical trials are needed to confirm these findings. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/4550 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/4550/2310