The Challenges in the Follow-Up and Treatment of Brazilian Children with Hereditary Angioedema.

Introduction Hereditary angioedema (HAE) with C1 inhibitor (C1-INH) deficiency is a rare autosomal dominant disease. Although the first symptoms can appear in childhood, the diagnosis's delay has a strong impact on the patient's quality of life. We analyzed clinical and laboratory characteristics and the drug therapy of pediatric patients with HAE in Brazil. Methods Medical records from 18 reference centers of HAE patients under 18 years of age were evaluated after confirmed diagnosis was performed by quantitative and/or functional C1-INH. Results A total of 95 participants (51 M:44 F; mean age: 7 years old) out of 17 centers were included; 15 asymptomatic cases were identified through family history and genetic screening. Angioedema attacks affected the extremities (73.5%), gastrointestinal tract (57%), face (50%), lips (42.5%), eyelids (23.7%), genitals (23.7%), upper airways (10%), and tongue (6.3%). Family history was present in 84% of patients, and the mean delay in the diagnosis was 3.9 years. Long-term prophylaxis (51/80) was performed with tranexamic acid (39/80) and androgens (13/80); and short-term prophylaxis (9/80) was performed with tranexamic acid (6/80) and danazol (3/80). On-demand therapy (35/80) was prescribed: icatibant in 7/35, fresh frozen plasma in 16/35, C1-INH plasma-derived in 11/35, and tranexamic acid in 12/35 patients. Conclusions This is the first study on HAE pediatric patients in Latin America. Clinical manifestations were similar to adults. Drugs such as androgens and tranexamic acid were indicated off-label, probably due to restricted access to specific drugs. Educational programs should address pediatricians to reduce late diagnosis and tailored child therapy.