D1.254 - Comparison Between Classical and Updated Classifications in Patients Diagnosed with Isolated Angioedema: Finally, Did We Find the Ideal One?

Angioedema (AE) is defined as intermittent, localized edema of the subcutaneous and submucosal tissues caused by a transient increase in vascular permeability. Different classification systems have been developed due to the heterogeneity and complexity of the underlying mechanisms. The DANCE classification defines three AE endotypes, two subtypes. This study compares classical and updated classifications.

Patients diagnosed with isolated AE between 2019 and 2025 were retrospectively assessed. Demographic characteristics, symptoms, AE frequency, triggers, treatments, and treatment responses were recorded. Patients were categorized based on classical and updated AE classifications.

Among 69 patients with isolated AE, 40 (58%) were female. The mean age and disease duration were 45.96 ± 14 years and 85.68 ± 116 months, respectively. Atopy was present in 33% of the patients. Twenty four percent of the patients (n = 17) had a family history of AE. The frequency of AE attacks was more than 12 per year in 39.1% of patients (n=27), 6-12 per year in 23.2% (n=16), and fewer than 6 per year in 30.4% (n=21). Angioedema resolved within 12-24 hours in 27.5% of patients (n=19) and within 48-72 hours in 26.0% (n=18). Angioedema most frequently involved the lips (72.5%, n=50), followed by the eyelids (60.9%, n=42) and the larynx (15.9%, n=11). The most common trigger was stress (58%, n=40), followed by trauma (24.6%, n=17), drugs (24.6%, n=17) and food (21.7%, n=15). Angioedema responded to antihistamines in 76.8% of patients (n=53), to corticosteroids in 66.7% (n=46), to icatibant in 15.9% (n=11), and to C1 esterase inhibitors in 13% (n=9). While all patients with non-IgE-mediated AE with or without urticaria (n=24) responded to antihistamines, none of those with idiopathic AE (n=7) did (p<0.001). Distributions based on two classifications are summarized in Table 1.

Hereditary AE type 1,2, and 3 patients were consistent with both classical and updated classification systems. Since ACE inhibitors and other drugs are grouped under the bradykinin-mediated category in the classical classification, medications such as NSAIDs couldn’t be appropriately classified. Isolated AE and IgE-/non-IgE-mediated AE with or without urticaria couldn’t be classified within the DANCE classification. Therefore we suggest adding IgE-/non-IgE-mediated AE with or without urticaria under the group of mast cell mediated AE in the DANCE classification.