What is HAE?

Hereditary angioedema (HAE) is a rare, potentially life-threatening genetic disorder. In most of the cases, HAE is caused by the deficiency or dysfunction of C1 esterase inhibitor (C1-INH).1-3 HAE can cause swelling attacks in the skin/subcutaneous tissue, gastrointestinal tract, and upper airways, some of which may be painful and functionally disabling.1,3,4

HAE affects about 1 in 10,000 to 50,000 people and is usually inherited, but it can manifest spontaneously from a new genetic mutation.5,6

Genetic disease6

Inherited gene

Types of HAE

There are two major subtypes of HAE, which present with the same signs and symptoms1:


Type I

Characterized by low levels of antigenic and functional C1 esterase inhibitor


Type II

Characterized by normal antigenic and low functional levels of C1 esterase inhibitor

HAE symptoms

Attacks can be unpredictable, often occurring without a known trigger, and can migrate to other parts of the body during a single episode.1,4

The severity and frequency of HAE attacks vary greatly from patient to patient and can also change over time.1,2 Before an attack, some patients may experience a prodrome, often a tingling sensation in the affected area. HAE attacks usually present without urticaria or pruritus. When untreated, the swelling in an HAE attack typically increases over a 24-hour period and then gradually subsides during the next 48–72 hours.1


Though each person will have a unique experience with HAE, some known triggers are:

  • Stress4
  • Physical trauma, surgery, or a dental procedure2,4
  • Infection2,4
  • Hormonal influences10
  • Mechanical pressure8

HAE attacks can have consequences.

HAE attacks can be debilitating and, in the case of laryngeal attacks, potentially life threatening.4 On average, an untreated patient will experience 2 to 4 attacks per month,1 usually lasting 2 to 5 days each.3,11

  • About 75% of patients experience an attack at least once a year§7
  • In a survey from 2010, 19-24% of patients underwent unnecessary procedures as a result of misdiagnosis, including removal of appendix||12
  • About 50% of HAE patients experience at least one laryngeal attack in their lifetime§7,8

Every patient with HAE, even those who have only experienced attacks in other locations, is still at risk for laryngeal attacks.1

§According to a survey of 209 patients
||In a survey of 313 patients

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  2. Zuraw BL, Banerji A, Bernstein JA, et al. US Hereditary Angioedema Association Medical Advisory Board 2013 recommendations for the management of hereditary angioedema due to C1 inhibitor deficiency. J Allergy Clin Immunol Pract. 2013;1(5):458-467.
  3. Cicardi M, Bork K, Caballero T, et al. Evidence-based recommendations for the therapeutic management of angioedema owing to hereditary C1 inhibitor deficiency: consensus report of an International Working Group. Allergy. 2012;67(2):147-157.
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  10. Nielsen EW, Gran JT, Straume B, Mellbye OJ, Johansen HT, Mollnes TE. Hereditary angio-oedema: new clinical observations and autoimmune screening, complement and kallikrein-kinin analyses. J Intern Med. 1996;239(2):119-130.
  11. Lumry WR, Castaldo AJ, Vernon MK, Blaustein MB, Wilson DA, Horn PT. The humanistic burden of hereditary angioedema: Impact on health-related quality of life, productivity, and depression. Allergy Asthma Proc. 2010;31(5):407–414.
  12. Lunn ML, Santos CB, Craig TJ. Is there a need for clinical guidelines in the United States for the diagnosis of hereditary angioedema and the screening of family members of affected patients? Ann Allergy Asthma Immunol. 2010;104(3):211–214.