Hereditary Angioedema (HAE) is a rare, genetic disorder characterized by recurrent episodes of severe swelling (angioedema) in various parts of the body, including the skin, gastrointestinal tract, upper airway, and limbs. Unlike typical allergic reactions, HAE is not caused by histamine release and does not respond to standard allergy treatments like antihistamines or corticosteroids.
HAE is most commonly caused by a deficiency or dysfunction of C1 esterase inhibitor (C1-INH), a protein that helps regulate inflammation and the immune response. The deficiency leads to uncontrolled activation of the bradykinin pathway, which increases vascular permeability and results in fluid leaking into surrounding tissues, causing swelling. HAE is inherited in an autosomal dominant manner, meaning only one copy of the defective gene is sufficient to cause the disorder.
Symptoms often begin in childhood or adolescence and can worsen over time. Swelling attacks may last for several days and can be extremely painful, especially when affecting the abdomen. Swelling of the airway can be life-threatening if not treated promptly. Unlike other types of angioedema, HAE is not accompanied by hives.
Diagnosis involves blood tests to measure levels and function of C1-INH and complement proteins. Early and accurate diagnosis is critical to prevent complications and improve quality of life.
There is no cure for HAE, but several effective treatments are available. These include C1-INH replacement therapy, bradykinin receptor antagonists, and kallikrein inhibitors to prevent or treat acute attacks. With proper management, individuals with HAE can lead full, active lives.
