Chronic spontaneous urticaria: from the hunt for causes and pathogenesis to the identification of different endotypes.

Summary: The hunt for the causes and pathogenic mechanisms involved in chronic spontaneous urticaria (CSU) has engaged clinicians and scientists for decades. Although not all aspects of the disease are defined, our knowledge has now improved to the point that we can consider CSU as an umbrella clinical phenotype under which several different endotypes probably exist. The present article will briefly summarize the fascinating history of the progress in our knowledge of this disease.