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Welcome to the Hereditary Angioedema (HAE) Pages


What is Hereditary Angioedema?

Hereditary angioedema (HAE) is a rare, potentially fatal genetic disorder characterized clinically by swelling of the extremities, face, trunk, abdominal viscera, and upper airway (1) . Abdominal attacks can cause severe pain, and mortality from oedema induced airway closure has been reported to be as high as 30% in affected patients. Certain procedures, such as dental work are known to trigger attacks and while patients in other stressful situations may suffer more attacks there are no definite triggers and attacks can come on at any time.

Although urticaria (itching) and angioedema are fairly common problems that affect nearly 20% of the population, HAE is a rare disease that accounts for about 2% of clinical angioedema cases (2) . The vast majority of patients who experience episodic swelling will be diagnosed with histamine mediated allergic angioedema. Epidemiological studies estimate the incidence of HAE at 1/10,000 to 1/50,000 individuals. This means that there may be up to 1850 patients in the UK . In contrast to allergic angioedema, HAE-related swelling is caused by an autosomal dominant genetic defect that results in reduced levels of or malfunctioning plasma protein C1 inhibitor (3) . Because defective C1-inhibitor does not adequately perform its normal regulatory function, an imbalance can occur and produce Bradykinin, a small protein that causes the capillaries to release fluids into surrounding tissues, thereby causing oedema. A child has a 50 percent chance of inheriting this disease if a parent possesses the genetic defect, however, the absence of family history does not rule out the HAE diagnosis. Scientists report that as many as one quarter of newly diagnosed HAE cases result from new mutations of the C1-inhibitor gene at conception (4) .

Because HAE is rare and the symptoms are varied, it is sometimes difficult for doctors to make the right diagnosis. Some patients have undergone multiple operations because their symptoms appear to be intestinal obstruction. Patients often suffer multiple attacks before being correctly referred to a Clinical Immunologist who will understand your condition and will be able to provide the
appropriate treatment for you.

(1) Frank MM, Gelfand JA, Atkinson JP. Hereditary angioedema: the clinical syndrome and its management. Ann Intern Med. 1976 May;84(5):580-93

(2) Frank M M,. Hereditary angioedema. Emedicine Series. http://www.emedicine.com/med/topic420.htm . 2/28/2006

(3) Agostoni, et. al. Hereditary and acquired angioedema: problems and progress: proceedings of the third C1 esterase inhibitor deficiency workshop and beyond. J Allergy Clin Immunol. 2004 Sep;114(3 Suppl):S55

(4) Pappalardo E et. al. Frequent de novo mutations and exon deletions in the C1inhibitor gene of patients with angioedema. J Allergy Clin Immunol. 2000 Dec;106(6):1147-54.




There is no ‘cure’ for HAE, however, there are drugs that are effective treatments for acute attacks and we will describe them below. If you are having more frequent attacks, your doctor may suggest that you take a medicine regularly to try and reduce the number of attacks you are having.


There are two drugs licensed for use in the UK for treating acute attacks of HAE. Berinert ® a C1 inhibitor concentrate and Firazyr ® ,a new drug called Icatibant.


C1- inhibitor is a plasma-derived intravenous therapy which has been used in the treatment and prevention of acute HAE. Berinert® (CSL Behring) is a freeze-dried C1- inhibitor concentrate and is obtained by separating the protein from lots of blood donations, which is then purified and filtered.


Icatibant (Firazyr®- Jerini/Shire) is a first in class Bradykinin B2 receptor blocker. It is a synthetic protein which is given by a subcutaneous injection. It works by preventing Bradykinin from causing the dilation of blood vessels and therefore stops the leakage of fluid which leads to oedema. Firazyr is licensed in all countries in Europe.



Three types of drugs are used to reduce the number of attacks that a patient may suffer; you may still get an acute attack while taking these so you should always be prepared to seek treatment for an acute attack.


Tranexamic Acid

Attenuated Androgens (e.g. Danazol, Stanozolol)


What can the PiA do for me?

The Primary Immunodeficiency Association (PiA) aims to improve the quality of life of all people with primary immunodeficiencies. For the HAE sufferer we can provide a wide variety of services and resources. These would include :

Publications such as the 'booklet' Understanding Hereditary Angioedema and Acquired C1-Inhibitor Deficiency'.

PiA information packs for the lay person and the professional.

Regional Days at different locations around the U.K. where members can meet up with others in similar situations.

Assistance with benefits. To download our Guide to Claiming DLA for persons with HAE , click....HERE

Condition Specific Contact : speak in confidence to another H.A.E. sufferer for advice and sharing of experiences

Online forums

For more information on any of the above topics please contact the PiA through the home page.

What is the Consensus Document?

The Consensus Document represents the outcome of discussion and research on the best practice for the diagnosis, treatment and management of C1-inhibitor deficiency.
It’s adoption will mean that there is a standard set out for patients that will ensure uniformity of treatment (hopefully) throughout the world.

To download the Consensus Document click here

Where can I find more information?

Understanding HAE (NEW PiA Booklet)

Patient stories :

Andy Long

Useful Links

hereditaryangioedema.com - US based site

http://www.thirdbass.co.uk - Andy's personal website