D1.310 - Phenotypes of patients with Hereditary Angioedema (HAE): a case series

Hereditary Angioedema (HAE) is a rare and potentially life-threatening condition that manifests clinically as recurring episodes of angioedema in the extremities, gastrointestinal tract, larynx, face, or urogenital area. It is typically caused by a deficiency (Type I) or dysfunction (Type II) of the C1 esterase inhibitor. However, there are some rare cases where patients with HAE have normal C1 esterase inhibitor. Long-term prophylaxis (LTP) aims to control the disease by preventing HAE episodes. Historically, medications such as androgens or tranexamic acid were used, but newer LTP treatments, including plasma-derived C1 inhibitor, Lanadelumab, and Berotralstat, are now available.

The Allergy Department of Laiko Hospital in Athens, Greece, is a Center of Expertise for the diagnosis and treatment of HAE. Since the late 1980s, 78 patients (39 women, 39 men) with HAE have been assessed and recorded. A review of these patients’ medical records was conducted, along with telephone interviews, from September 2024 to January 2025. However, contact and follow-up was successfully made with 59 of these patients (31 women, 28 men).

Of the 59 patients, 45 have Type I HAE, 10 have Type II HAE, and one has HAE with normal C1 esterase inhibitor. The median age of disease onset is 10 years. A family history, either suspected or confirmed, is present in 43 patients. Nearly all patients have experienced episodes in the extremities or gastrointestinal tract during their lifetime, while 31 out of 59 have had episodes involving the larynx. The most common trigger for episodes is reported to be stress, and 34 out of 59 patients report prodromal symptoms prior to HAE episodes. Overall, 40 patients have used older-generation medications in the past, while 43 are currently using newer LTP treatments.

The phenotypes of patients with HAE in this cohort align with those reported in international literature, though some differences are evident. Case series like ours provide valuable insights into this rare disease.