Clinical features of hereditary angioedema in Chinese patients: New findings and differences from other populations

Background: Hereditary angioedema (HAE), caused by C1 inhibitor deficiency, is characterized by recurrent subcutaneous or submucosal swelling. Because it is rare, data on clinical features, especially in Chinese patients, are not comprehensive. Objective: Our aim was to identify the characteristics of HAE in a Chinese population and enhance clinical knowledge of this disease. Methods: One hundred and fifty-eight symptomatic patients were studied retrospectively. Data were obtained from medical records. Statistical analyses were performed using statistical software package: R version 2.14.0. Results: The majority of patients first experienced attacks during the second (42%) and third (32%) decades: the mean onset of symptoms was at the age of 21.25 years. The percentage of patients having experienced a swelling at least once for the following sites were: extremities (83.54%); pharyngolarynx (58.86%); face (55.06%); gastrointestinal tract (34.17%); trunk (18.35%) and genitalia (15.33%). Rare manifestations included melaena, swollen gastric mucosa inverting into the oesophagus, pleural effusion, dysuria and syncope. For patients who first experienced swelling in pre-adolescence, 41.67% noted intensified attack rates when they entered puberty. In pregnancy, 61.70% did not note a change in HAE attack frequency. Conclusion: Compared with previous studies, the mean age of symptom onset is older. The frequencies of abdominal attacks occurring in patients on the Chinese Mainland, as well as in Taiwan and Japan, appears much lower than in western countries. Ethnic or environmental differences may contribute to this finding. Melaena and gastric mucosa inverting into the oesophagus secondary to edema are first reported here.