Clinical Remission of Chronic Spontaneous Urticaria (CSU): A Targeted Literature Review

Introduction Chronic spontaneous (previously known as idiopathic) urticaria (CSU) is a chronic skin disease with the potential for natural remission. The objectives of this targeted literature review were to identify evidence on the clinical course of CSU, including remission rates, and to estimate cumulative remission rates for different time points. Methods Electronic databases (MEDLINE, MEDLINE-In Process, Embase, Web of Science, BIOSIS Previews and the Cochrane Library) and relevant conference proceedings were searched to identify studies involving patients with CSU aged ≥ 12 years that provide data on remission rates and disease duration. Observational studies with patient follow-ups of ≥ 1 year or review articles were included. Data extracted from five selected studies were used to run Kaplan–Meier (KM) analyses and best-fit distributions to calculate remission rates per 4-week period and weighted averages. Results Ten publications were included in this review. The proportion of patients achieving remission within year 1 ranged from 21 to 47%, while reported remission rate estimates at year 5 were 34% and 45%. Based on calculated 4-weekly remission rates, cumulative remission estimates ranged from 9 to 38% at year 1, from 29 to 71% at year 5 and from 52 to 93% at year 20. Cumulative weighted average estimates for the proportion of patients remitting at years 1, 5 and 20 were 17%, 45% and 73%, respectively. Conclusions Published evidence suggests that CSU is a self-limiting condition with variable disease severity and duration, apparently dependent on multiple factors. However, data sources differed in terms of definitions of disease severity and remission, as well as in conclusions on influencing factors. Further studies and uniform definitions are required.