What is hereditary angioedema?

Hereditary angioedema (HAE) is a rare genetic condition that causes recurrent episodes of swelling in different parts of the body. The swelling can affect the face, hands, feet, abdomen (causing severe pain), and (most dangerously) the throat, where it can cause airway obstruction.

Why it is different from allergic angioedema. Allergic angioedema is driven by histamine and responds to antihistamines and corticosteroids. HAE is driven by a different molecule called bradykinin and does not respond to antihistamines or corticosteroids. Misattributing HAE attacks to allergy can delay correct diagnosis for years.

The biology. Most people with HAE have a deficiency of a protein called C1 esterase inhibitor, which normally keeps bradykinin production in check. Without enough working C1 inhibitor, bradykinin can be over-produced, leading to leaky blood vessels and swelling. A diagnostic blood test for C1 inhibitor activity is the gate to correct identification.

The therapy options.

Long-term prophylaxis: medicines taken regularly to prevent attacks. Lanadelumab is an injection given every two to four weeks. C1 esterase inhibitor concentrate replaces the missing protein. Berotralstat is an oral once-daily medicine that blocks the kallikrein enzyme upstream of bradykinin. Follow-on oral medicines and other mechanism classes are in development.

On-demand therapy: medicines taken to stop an attack that has already started. Several options exist as injections; oral on-demand medicines are entering the picture.

What to expect. With modern prophylactic therapy, most patients see substantially fewer attacks. The expanded oral options are particularly meaningful for people who have struggled with regular injections. Carrying on-demand therapy and a written action plan remains important because attacks, particularly throat-area attacks, can be dangerous and need fast treatment.