Chronic histaminergic angioedema (CHA) and angioedema associated with chronic spontaneous urticaria (AE-CSU) may be independent pathologies, according to the authors of a paper published in The Journal of Allergy and Clinical Immunology Global. Ana Láinez-Nuez, MD, PhD, and colleagues conducted an observational, retrospective study involving 56 patients with CHA and 40 with AE-CSU, analyzing data from the year before and after diagnosis to examine the clinical and evolutionary characteristics of each condition. Patients with AE-CSU experienced more frequent angioedema attacks compared to patients with CHA, both before and after diagnosis. Additionally, CHA more commonly affected the uvula. Using a logistic regression model based on seven clinical characteristics, the study achieved a high specificity (86.4%) and sensitivity (92.3%), with an area under the curve of 95.1%, in differentiating between the two conditions. The researchers concluded their findings support the idea that CHA and AE-CSU, despite their similarities, may indeed be distinct entities due to the differences in attack frequencies and locations.