What is HAE?

HAE is an inherited condition. If a parent has HAE, there is a 50% chance they will pass it on to their children. Family members who have been tested and who do not have HAE will not pass the disease on to their children.

HAE can also occur with no family history as a spontaneous gene mutation.

HAE is characterised by huge swelling of the tissues (angioedema) which last from three to five days. These swellings can occur on any part of the body; hands and feet, arms and legs, trunk, intestines, genital organs, face, tongue, neck and airway (larynx).

Because the disease is very rare, it is not uncommon for patients to remain undiagnosed for many years.

An example of hand swelling

Left – Normal (no swelling), Right – Untreated HAE attack (swelling)

An example of gastrointestinal swelling

Left – Normal (no swelling), Right – Untreated HAE attack (swelling)
Note – some internal swelling may not show externally

An example of facial swelling

Left – Normal (no swelling), Right –Untreated HAE attack (swelling)

An example of throat swelling

Prodromal symptoms

Some patients can identify warning symptoms (prodomal symptoms) in the 24 hours before an attack. These symptoms can include extreme tiredness, a rash or tingling over the affected site.

An example of a HAE rash

HAE attacks can start at any time from early childhood, in adolescence or later in life.The frequency of attacks can vary from once or twice a year to every few days in the most severely affected patients.Intestinal swelling causes sickness and diarrhoea and very severe pain.

Swelling of the face and tongue can lead to swelling of the airway which is life threatening.

HAE-related swelling is NOT the same as swelling caused by allergies and cannot be treated as an allergic reaction. Antihistamines, corticosteroids (prednisone), and epinephrine are ineffective in relieving angioedema symptoms of HAE