The Effect of Omalizumab Therapy on Systemic Inflammatory Parameters in Chronic Spontaneous Urticaria

INTRODUCTION: Chronic spontaneous urticaria (CSU) is a disorder characterized by the triggering of mast cells and basophils and is thought to involve systemic inflammatory responses. Hematological parameters obtained from the complete blood count, particularly the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), have been considered potential biomarkers associated with systemic inflammatory processes. The purpose of this study was to examine the impact of omalizumab therapy on inflammatory parameters, including C-reactive protein (CRP), NLR, and PLR in patients diagnosed with CSU.
METHODS: Data from 44 individuals with CSU who were followed at the Dermatology Clinic of Haydarpaşa Numune Training and Research Hospital between June 2022 and June 2024 and received omalizumab therapy for at least 1 year were retrospectively analyzed in this observational study. CRP, NLR, and PLR levels were compared before treatment, at the 6th month of therapy, and at the end of the 1st year. In addition, the relationship between baseline urticaria activity score (UAS7) and these inflammatory parameters was assessed.
RESULTS: The study population had an average age of 48.57±13.43 years. Among the participants, 65.9% were women and 34.1% were men. Throughout the omalizumab treatment period, CRP and NLR levels demonstrated a statistically significant decrease (p<0.001). In addition, PLR values also decreased, with a notable reduction observed at the 6th month of therapy (p=0.029). Analysis of relationships between variables revealed a moderate positive association between baseline UAS7 values and both CRP and PLR levels, while a robust positive association was demonstrated between baseline UAS7 and NLR (r=0.864; p<0.001).
DISCUSSION AND CONCLUSION: These findings may be associated not only with clinical improvement but also with reductions in certain systemic inflammatory markers. The strong association between baseline NLR and disease activity indicates that NLR may serve as a practical, accessible biomarker in CSU.

Keywords: Chronic spontaneous urticaria, C-reactive protein, lymphocytes, neutrophils, omalizumab.