KLK4 and hereditary angioedema: In several countries, formulations of pdC1‐INH are indicated for HAE attacks in children aged 12 years and younger.4 A systematic review of pdC1‐INH for HAE attacks in pediatrics, including children less than 12 years of age, reported efficacy and safety results similar to those observed in adults.29 Ecallantide, a plasma kallikrein inhibitor indicated for acute treatment in patients who are at least 12 years of age, exhibited a safety and efficacy profile30 similar to that observed in adults with HAE.