What is HAE?

Hereditary angioedema (HAE) is a rare genetic disorder characterised by episodes of swelling (edema) in different areas of the skin or the internal organs. In particular, it occurs in the upper respiratory tract and intestine.

Edema of the skin occurs mainly on the face including lips, eyelids, although the extremities and genitalia are also often affected. In many cases, the affected area can be painful, especially if it is close to junctions. Although it is not life-threatening, people with this kind of edema often withdraw from their social lives because of the disfiguration it causes.
 
Approximately one in three of those affected with HAE will have edema of the mucous membranes of the larynx, nose or tongue at least once in their lifetime. It is potentially life-threatening and if appropriate treatment is not administered, it is estimated that a third of these patients die early from suffocation. 
 
In approximately one in four patients, intestinal edema predominates. This manifests itself primarily as loss of appetite, nausea, vomiting and abdominal cramps. If HAE has not yet been diagnosed in these patients, suspicion of colic or appendicitis can lead to unnecessary surgical procedures or even to removal of healthy organs.
 
It is estimated that about 1 in 10,000 to 1 in 50,000 people have HAE. However, experts believe that this maybe an underestimate, as it is often diagnosed incorrectly or not diagnosed for many years in patients with no family history of the disease. It occurs with roughly the same frequency in men and women. In 75 per cent of those affected, it occurs within the first 20 years of life.
 
The development of edema does not follow a typical pattern and therefore the site of the next episode of swelling cannot be predicted. The frequency, duration and severity of the edema varies considerably. Most patients have an average of one episode of swelling per month, although for some patients it can occur weekly or only twice a year. In most cases, the edema develops gradually over a period of 12-36 hours and then subsides spontaneously within 2-5 days.
 
Patients can sometimes link specific situations that occur in their lives, such as stress, infections or even the consumption of certain foods, that ’trigger’ the development of edema, although often no trigger mechanism can be clearly identified.
 
The disease places extraordinary strain on patients. Depending on its severity, just one episode per month makes it impossible to have a social and professional life for 20-100 days a year. There is also the constant worry about the next, possibly life-threatening episode. In addition patients are restricted in their travel, as at present, acute episodes in many cases must be treated effectively by a doctor, preferably at a centre with experience of HAE.