Prevalence of chronic urticaria refractory to antihistamines in Andalucia, Spain.

Chronic urticaria (CU) has a devastating effect on the quality of life of patients who suffer from it. The objective of this study is to determine the prevalence of severe chronic spontaneous urticaria (CSU) in adults in eight health areas in Andalucía. A retrospective observational study from January 2019 to December 2019 was conducted with the participation of seven reference hospitals that were analyzed, including a total reference population of 3 159 001 individuals ≥18 years. The analysis was carried out on the characteristics of the population and the estimated prevalence. In total, 369 patients with a diagnosis of CSU refractory to antagonist of histamine were registered. We have found a prevalence of refractory patients of 0.0012% (95% CI 0.0010%-0.0013), ranging from 0.006% to 0.02%. The present study has helped to describe the prevalence and characteristics of patients with severe urticarial. The prevalence is lower than previously reported. We have observed differences between hospital areas. There will be a new line of research at the national level to help improve the identification of patients with CSU.