Hereditary angioedema is characterized by recurrent episodes of severe swelling (angioedema). The most commonly involved areas of the body are the limbs, face, intestinal tract, and airway. While minor trauma or stress may trigger an attack, swelling often occurs without a known trigger. Episodes involving the intestinal tract cause severe abdominal pain, nausea, and vomiting. Swelling in the airway can restrict breathing and lead to life-threatening obstruction of the airway. About one-third of people with this condition develop a non-itchy rash called erythema marginatum during an attack.
Symptoms of hereditary angioedema typically begin in childhood and worsen during puberty. Untreated individuals may have an attack every 1 to 2 weeks. Most episodes last 3 to 4 days. The frequency and duration of attacks vary greatly among individuals with hereditary angioedema, even among those in the same family.