← All diseases

Blood and immune system diseases

Hereditary angioedema (HAE)

An inherited disease that causes repeated episodes of severe swelling in the face, hands and feet, or the bowel. Swelling in the throat can make breathing difficult and may be life-threatening.

Not part of the panel of Türkiye's National Newborn Screening Programme (heel-prick test). Source

Orphanet has a guideline for emergency doctors for this disease (language: English, Spanish, French, Italian, Polish, Portuguese). See on Orphanet

Prepare an emergency card

This page is translated from the Turkish original.

This disease is followed through the “Blood and immune system diseases” group.

Understanding the disease

This section has not yet been reviewed by a physician. It summarises patient information from sources such as MedlinePlus, Orphanet and the NHS in plain language. The disease can differ from person to person; talk to your doctor about diagnosis and treatment.

What happens in this disease?

In HAE, a protein in the blood called C1 inhibitor is low or does not work. In some types, however, this protein is normal. As a result, repeated swellings (edema) occur in different parts of the body. Swelling in the throat can narrow the airway and be life-threatening.

Which symptoms can occur?

Symptoms often begin in childhood and increase in adolescence. The swellings do not itch and often last a few days.

  • Swelling of the hands, feet, arms or legs (common)
  • Swelling of the face (common)
  • Severe abdominal pain, nausea and vomiting due to swelling in the bowel (common)
  • Swelling in the throat and difficulty breathing (sometimes; can be life-threatening)
  • Attacks that start without a clear reason (common)
  • Attacks that start after a minor knock or stress (sometimes)
  • In people not receiving treatment, on average one attack every 1–2 weeks

How is it diagnosed?

Repeated swellings and a similar history in the family raise suspicion. Blood tests measure the C4 level and the amount and function of C1 inhibitor. In some types, these tests are normal. Then the diagnosis is based on the symptoms and the history.

Treatment and care

Treatment has two sides. During attacks, treatments that stop the swelling are used. There are also short-term or long-term preventive treatments to prevent attacks. Cortisone-type medicines are not effective for these swellings. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

HAE is often passed on through a single changed gene. So for each child of a parent with the disease, the risk is 50%. Sometimes the gene change appears for the first time in the family. Screening of family members, including those without symptoms, is recommended.

Source: MedlinePlus Genetics — Hereditary angioedema · Orphanet — Hereditary angioedema (ORPHA:91378)

Key facts

How common is it?
Prevalence: 1-9 per 100 000 (Europe)
How is it inherited?
Autosomal dominant
When does it usually start?
Any age

These facts are taken from Orphanet and MedlinePlus records (last checked: October 7, 2026). Frequency values are approximate ranges.

You are not alone: patient associations in Türkiye

Non-profit patient and family organizations in Türkiye working on this disease or disease group. Links are for information; Doktorclub is not affiliated with these organizations and does not endorse them.

For all rare diseases: Nadir Hastalıklar Federasyonu

Links checked on October 8, 2026.

Support and help

Doktorclub does not diagnose, recommend treatments or refer you to hospitals or doctors. These pages are meant to help you talk with your doctor.

News about HAE

Clinical trials (ClinicalTrials.gov)

A clinical trial is a regulated study that tests whether a new treatment is safe and whether it works, in patients who volunteer. Most trials look for a certain age, genetic change and health condition. Taking part is voluntary.

This list is not a treatment recommendation. Treatments tested in phase 1–3 trials are investigational (experimental): their efficacy and safety have not yet been proven and they are not approved treatments. Taking part depends on each trial’s criteria and a physician’s assessment; the first step is to talk to the doctor who manages your care.

Questions you can ask your doctor

  • Could this trial be suitable for us?
  • If we take part, how would current treatment and check-ups be affected?
  • Where does the trial take place, and how are travel and accommodation handled?
  • What happens if we want to leave the trial?

ClinicalTrials.gov lists 21 active interventional studies for this disease. 7 are recruiting now; 6 have sites in Türkiye. Last checked: October 7, 2026.

Selected records (studies with a site in Türkiye first):

See all studies on ClinicalTrials.gov · Joining clinical trials

Blood and immune system diseases: other news

Medical codes (for talking with your doctor and finding sources)

These codes identify the disease in international classifications and databases. They can help when you talk with your doctor or look for reliable sources.

Orphanet code: ORPHA:91378 · ICD-11 4A00.14

Codes checked against WHO ICD-11 and Orphanet on October 6, 2026.

This page provides general information and does not replace diagnosis or treatment. Talk to your doctor about symptoms, diagnosis and treatment.

The information on these pages is for general information only and does not replace medical advice. Talk to your doctor about diagnosis and treatment decisions. In an emergency in Türkiye, call 112.

Every update is based on an open source and labeled with its level of evidence. No advertising and no drug brand names. Our scientific principles

This page was translated from Turkish by the Doktorclub editorial team.