Urticaria is characterized by the transient appearance of hives, angioedema, or both. Acute urticaria lasts less than 6 weeks. The origin is idiopathic in more than 50% of cases, and the most frequent triggers are infectious processes, drugs and foods.Describe the origin, pathophysiology and treatment of patients with acute urticaria.A bibliographic search of articles was carried out in PubMed, where the Mesh terms: "Urticaria", "Angioedema" and "Antihistamines" were included and those with information related to acute urticaria were chosen, among those published from 2014 to 2023. In addition, the inclusion of some publications from previous years was considered, due to their relevance for this review.The initial search returned 135 articles, but only 104 were used for the final manuscript.Acute urticaria is one of the most frequent reasons for consultation in the Allergology and Dermatology emergency services. Although there are multiple etiological factors, most cases are idiopathic, so it should not be overdiagnosed as an allergic reaction.