Components in the venom of a pit viper include histamine and bradykinin-like factors that can cause systemic effects.10 Given that the mechanism of angioedema from ACEI is thought to be through bradykinin release and that our patient had a pit viper envenomation, the delayed angioedema may have been a result of both synergistically interacting. The gene discussed is KNG1; the disease is angioedema.