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HAE causes episodic attacks of oedema of the skin and mucosal surfaces in various parts of the body.1 Common attack sites include:1–3

  • Abdomen
  • Mouth / face
  • Throat
  • Genitals
  • Hands
  • Feet



Attacks of swelling are unpredictable in frequency and severity, and they can be life threatening when they occur in the upper respiratory tract.2-4 Asphyxiation by laryngeal oedema is the main cause of death among patients who die of HAE.5



In an emergency setting, HAE is often misdiagnosed and inappropriately treated as another condition such as:

  • An allergic reaction6,7
  • Appendicitis6,7
  • Biliary disorder6
  • A gastrointestinal disorder,6,7 such as:
    • Gastroesophageal reflux disease (GORD)6
    • Peptic ulcer6
    • Irritable bowel syndrome (IBS)7


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Misdiagnosis can lead to unfavourable outcomes – fatal laryngeal attacks are commonly attributed to failures in recognising and appropriately managing and treating HAE, often as a result of misdiagnosis.8


Correct identification of HAE in patients who present to the emergency department with oedema is critical for the rapid and effective treatment of severe acute attacks.8


An HAE attack may last for days if left untreated.9 The symptoms of oedema and pain typically worsen over a 24-hour period and can last for 3 to 5 days.9,10

Although clinical symptoms can first present at any time from early childhood, onset typically begins within the first two decades of life, and often in the first decade.11,12

The frequency and severity of attacks is highly variable among patients with HAE – even within the same family – ranging from once or twice a year to every few days in the most severely affected patients.13


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Attack history is not a predictor of future attack frequency, severity or location.3-5

Clinical presentation

Patients with HAE present with one or more of the following hallmark indicators:12

Recurrent angioedema, frequently on the extremities and face

Affects most patients with HAE

Intermittent abdominal pain

Presents in as many as 93% of patients

Positive family history

In approximately 75% of patients


Prodromal symptoms

Prodromes can be predictive of an attack in some cases and are often described as:16,17

  • Fatigue or malaise
  • Erythema marginatum
  • Restlessness
  • Nausea
  • Joint pain
  • Cramps
  • Anxiety or mood changes
  • Prickling sensation
  • Skin tightness


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The disease burden of HAE may extend beyond attacks into everyday life. Due to its unpredictable nature, HAE can cause substantial emotional, psychosocial, and quality-of-life impairments for patients and their caregivers.14,15


  1. Longhurst HJ, et al. Br J Hosp Med (Lond) 2006;67(12):654–7.
  2. Maurer M, et al. Allergy 2018;73(8):1575–96.
  3. Banerji A, et al. Allergy Asthma Proc 2015;36(3):213–7.
  4. Farkas H, et al. Allergy 2017;72(2):300–13.
  5. Bork K, et al. Arch Intern Med 2003;163(10):1229–35.
  6. Zanichelli A, et al. Ann Allergy Asthma Immunol 2016;117(4):394–8.
  7. Marks J. Available from: Accessed August 2021.
  8. Moldovan D, et al. Case Rep Emerg Med 2018;2018;6363787.
  9. Longhurst H, et al. Lancet 2012;379(9814):474–81.
  10. HAE UK. Available from: Accessed August 2021.
  11. Bygum A, et al. Clin Transl Allergy 2019;9:37.
  12. Henao MP, et al. Ther Clin Risk Manag 2016;12:701–11.
  13. Bernstein JA. Am J Manag Care 2018;24(14 Suppl):S292–8.
  14. Longhurst H, et al. Clin Rev Allerg Immunol 2016;51(2):230–9.
  15. Bygum A, et al. Acta Derm Venereol 2015;95(6):706–10.
  16. Caballero T, et al. J Investig Allergol Clin Immunol 2016;26(6):383–6.
  17. Prematta MJ, et al. Allergy Asthma Proc 2009;30(5):506–11.
Job code: C-ANPROM/UK//2467 Date of preparation: August 2021