A nationwide cohort study conducted in South Korea revealed that bariatric surgery can have a significant impact on the control of disease in obese patients with chronic urticaria, reducing the need for long-term medication. Chronic urticaria is an inflammatory disease of the skin characterized by the presence of recurring wheals, pruritus, and, in some cases, angioedema. The study was published in The Journal of Allergy and Clinical Immunology by Juhee R. and colleagues.Chronic urticaria has been increasingly related to metabolic disorders, including obesity, which is now considered a chronic inflammatory disease that results in immune system dysfunction and the overproduction of inflammatory markers. Obesity has been shown to increase the incidence and severity of chronic urticaria, making the possibility of the effect of weight reduction on the activity of the disease an interesting issue. Bariatric surgery is now considered the most effective method for the management of severe obesity, resulting in weight reduction of 20–35%.A large-scale population-based cohort study was done using the Korean National Health Insurance database between 2019 and 2022. In this study, the population included 3,817 adult patients undergoing bariatric surgery. Changes in the pattern of medication prescriptions were evaluated in two different time periods, namely, the two years preceding the surgery and the two years following the surgery, in order to assess the changes in the pattern of medication prescriptions in the treatment of chronic urticaria.Chronic urticaria was identified based on the International Classification of Diseases, Tenth Revision (ICD-10) coding system, with a diagnosis of L50 recorded in the database before the surgery. Changes in the pattern of prescriptions of the most commonly used medications in the treatment of chronic urticaria, such as antihistamines and leukotriene receptor antagonists, were evaluated in the study. In the study, the effect of weight loss on the pattern of medication prescriptions in the treatment of chronic urticaria was evaluated in the population of patients undergoing bariatric surgery and those with a diagnosis of chronic urticaria.Key findings:The study is a nationwide cohort study that consisted of 3,817 patients undergoing bariatric surgery in the period 2019 to 2022. Among the patients, 873 patients with chronic urticaria before bariatric surgery constituted 22.9 percent of the total patients undergoing bariatric surgery. Among these patients with chronic urticaria, 97.7% of patients received antihistamines before bariatric surgery, which decreased to 58.8% at one year and 63.6% at two years after bariatric surgery. In the case of leukotriene receptor antagonists, 33.0% of patients received the drug before bariatric surgery, which decreased to 8.0% at one year and 7.0% at two years after bariatric surgery.Bariatric surgery was significantly associated with reduced usage of medication for chronic urticaria in obese patients, based on this nationwide study. The usage of medications such as antihistamines and leukotriene receptor antagonists significantly decreased during the two years following the surgery, suggesting that the disease is better managed with significant weight loss. This study shows the importance of weight management in the treatment of chronic urticaria and obesity, and also suggests that the treatment of obesity through surgery could provide an additional benefit in the treatment of the disease itself.Reference:Ryu, J., Kim, S., Kwon, J.-W., & Jeong, J. (2026). Weight reduction through bariatric surgery improves disease control in chronic urticaria: Evidence from Korean national health insurance data. The Journal of Allergy and Clinical Immunology, 157(2), AB32. https://doi.org/10.1016/j.jaci.2025.12.099