Hereditary angioedema (HAE) is a rare genetic disorder characterized by recurrent episodes of severe swelling (angioedema) in various parts of the body, including the extremities, face, gastrointestinal tract, and airways. This condition is caused by a deficiency or dysfunction of C1-inhibitor, a protein that regulates the complement system, part of the immune response. Without proper regulation, the complement system can trigger excessive inflammation and fluid leakage from blood vessels, leading to swelling.
HAE typically presents in childhood or adolescence, though the severity and frequency of episodes can vary widely among individuals. Common symptoms include painful swelling in the hands, feet, and face, abdominal pain and cramping due to intestinal swelling, and potentially life-threatening airway swelling that can cause breathing difficulties. Unlike other forms of angioedema, HAE does not respond to typical allergy treatments like antihistamines or corticosteroids.
Diagnosis of HAE involves measuring levels and function of C1-inhibitor and complement components in the blood. Once diagnosed, management focuses on preventing and treating acute attacks. Long-term prophylactic treatments may include C1-inhibitor replacement therapy, androgens, or antifibrinolytics. Acute attacks are treated with C1-inhibitor concentrates, bradykinin receptor antagonists, or kallikrein inhibitors to quickly reduce swelling.
Living with HAE requires careful planning to avoid triggers, such as stress, trauma, or certain medications. Patients should have access to emergency treatment and wear medical alert identification. With appropriate management and education, individuals with HAE can lead relatively normal lives, despite the challenges posed by this condition.