What is the primary clinical manifestation of hereditary angioedema?

Hereditary angioedema is primarily characterized by episodes of swelling known as angioedema, which typically occurs in various parts of the body, including the face. The underlying cause of hereditary angioedema relates to deficiencies or dysfunctions in the C1 inhibitor protein, leading to uncontrolled activation of the complement and contact systems. The most noticeable and worrying manifestation is indeed facial edema, which can also affect other areas like the extremities, gastrointestinal tract, and upper respiratory system.

Facial swelling can manifest acutely and make it difficult for individuals to breathe or swallow, warranting immediate medical attention. While other symptoms like severe abdominal pain may occur due to swelling in the gastrointestinal tract and joint swelling can happen when angioedema affects other tissues, the hallmark symptom that is most recognizable and clinically significant is the edema that appears notably in the face. This makes facial edema the primary clinical manifestation of hereditary angioedema.