Farkas H, et al. - Given that plasma-derived C1-inhibitor (pdC1-INH) represents a first-line treatment for hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) in pediatric patients, researchers focused on the clinical features as well as the safety of management with pdC1-INH in this population. A prospective, long-term survey was conducted. Overall 3,009 HAE attacks were encountered by 70 pediatric patients (31 boys and 39 girls). In 70 patients, 37 took pdC1-INH for 456 HAE attacks, or as prophylaxis (69 vials). In distinct age groups, the distribution of pdC1-INH use was as follows: no use (0-1 years), 0.11 vials/year (1-3 years), 0.7 vials/year (3-6 years), 1.26 vials/year (6-12 years), and 1.28 vials/year (12-18 years). With this drug, systemic allergic reactions, viral transmission, development of anti-C1-INH antibodies, or thromboembolic events did not occur. Findings corroborated the existence of disparity in clinical manifestations and the use of pdC1-INH in various age groups of pediatric patients with C1-INH-HAE. In this patient population, the safety of the use of pdC1-INH was shown in the long-term survey.