Omalizumab on Chronic Spontaneous Urticaria and Chronic Inducible Urticaria: A Real-World Study of Efficacy and Predictors of Treatment Outcome

Background: Omalizumab is a very important drug for the treatment of chronic urticaria. Although omalizumab's therapeutic efficacy has been demonstrated, data on real-world experiences in Korea, especially regarding chronic inducible urticaria (CIndU), are limited. This study attempted to compare the efficacy of omalizumab in Korean chronic spontaneous urticaria (CSU) and CIndU patients. Methods: Fifty-two CSU and 29 CIndU patients were included and Urticaria Activity Score 7 (UAS7) at baseline, week 4, and week 12 was assessed retrospectively. Results: Omalizumab 150 mg significantly decreased UAS7 in both patients with CSU and CIndU with only one dose (P < 0.001). The significant decrease in the UAS7 scores of both groups of patients continued from weeks 4 to 12. Although there was no significant difference in treatment efficacy between the two groups, the symptoms of patients with CSU tended to improve faster; furthermore, the number of antihistamines administered daily reduced more significantly in this patient group (P = 0.047). Additionally, the decrease in the UAS7 score between baseline and week 12 and the response rate were higher in patients with CSU. Conclusion: Omalizumab may be slightly more effective against CSU than against CIndU. Regarding the CIndU subtypes, dermatographic urticaria was associated with the greatest reduction in the UAS7 score, and patients with this condition showed the highest response rate, indicating the best effect of omalizumab. The duration of chronic urticaria was greater in non-responders than in responders (P = 0.025). Conversely, baseline immunoglobulin E levels were significantly higher in responders (P = 0.039).