Question: Hereditary angioedema may be clinically confused with severe drug related reactions in some circumstances. What is hereditary angioedema and what is the cause for hereditary angioedema?
Answer: The cited reference notes: “Hereditary angioedema is a disabling and potentially fatal condition characterized by recurrent episodes of swelling without urticaria or pruritus. The condition is caused by deficiency (type I) or dysfunction (type II) of the C1 inhibitor protein, Patients have insufficient C1 inhibitor function to prevent bradykinin production by the contact system, leading to episodes if increased capillary hyper-permeability and swelling. These episodes manifest clinically as angioedema attacks.” (Longhurst H et al. Prevention of hereditary angioedema attacks with a subcutaneous C1 inhibitor. 2017 NEJM 376(12): 1131-1140)