Natural course of new-onset urticaria: Results of a 10-year follow-up, nationwide, population-based study

Background: Previous epidemiologic studies of the natural course of urticaria mainly focused on chronic spontaneous urticaria and were conducted at hospitals. The natural course of new-onset urticaria in the general population is unknown. Methods: Patients with new-onset urticaria were identified from the National Health Insurance Service -National Sample Cohort data. Patients who had at least one visit for urticaria in 2002 and 2003 were excluded and the study cohort consisted of 1,027,620 subjects with no history of urticaria. We analyzed cumulative incidences of urticaria, chronic urticaria, and chronic urticaria remission using the life table estimation method from 2004 to 2013. Their association with related factors was analyzed using the Cox proportional hazards analysis. Results: From 2004 to 2013, a total of 49,129 patients with new-onset urticaria were identified. The 10-year cumulative incidence rate of urticaria for the general population was 4.9% and that of chronic urticaria among patients with new-onset urticaria was 7.8%. Remission rates of chronic urticaria were 52.6% at 1 year and 88.9% at 5 years. Age, sex, residential area, and autoimmune thyroid disease were significantly associated with urticaria or chronic urticaria, but not with chronic urticaria remission, after adjusting for covariates. Female individuals were more likely to have new-onset urticaria but less likely to develop chronic urticaria compared with male individuals. Conclusions: During the 10-year follow-up period, only a small proportion of patients with new-onset urticaria developed chronic urticaria. Remission was achieved in the majority of patients with chronic urticaria regardless of demographic characteristics or accompanying thyroid disease. Copyright (C) 2018, Japanese Society of Allergology. Production and hosting by Elsevier B.V.