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Hereditary angioedema
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Hereditary angioedema

Hereditary angioedema is a genetic disorder characterized by recurrent episodes of severe swelling in various parts of the body, including the face, intestinal tract, and airway.

Overview

Hereditary angioedema (HAE) causes recurring, severe swelling that can be triggered by minor trauma or stress, though it often occurs without a known trigger. Swelling in the airway can be life-threatening, while intestinal involvement often leads to severe abdominal pain, nausea, and vomiting. Symptoms typically begin in childhood and worsen during puberty.

Types

The condition is broadly divided into two categories based on the levels and function of the C1 inhibitor (C1-INH) protein:

  • Hereditary angioedema due to C1-INH deficiency: Divided into Type I (low levels of C1-INH) and Type II (C1-INH protein does not function correctly).
  • Hereditary angioedema with normal C1-INH: A distinct form often associated with other genetic variants.

Causes

The condition is caused by genetic variants that lead to an excess of a protein fragment called bradykinin, which promotes inflammation and increases fluid leakage through blood vessel walls:

  • SERPING1 gene: Variants in this gene cause HAE due to C1-INH deficiency.
  • F12 gene: Variants in this gene cause most cases of HAE with normal C1-INH by producing a factor XII protein that is easier to activate than normal.

Inheritance

Hereditary angioedema is inherited in an autosomal dominant pattern, meaning one copy of an altered gene in each cell is sufficient to cause the disorder. Some cases result from new (de novo) mutations in individuals with no family history of the condition.

Other Names

  • C1 esterase inhibitor deficiency
  • C1 inhibitor deficiency
  • HAE
  • HANE
  • Hereditary angioneurotic edema

Frequently Asked Questions

Signs of impending airway compromise include sudden swelling of the lips, tongue, or throat, difficulty swallowing, hoarseness, or a feeling of tightness in the chest. If these symptoms appear, call emergency services immediately and, if you have a self‑administered medication kit, use it right away (e.g., icatibant or a C1‑INH concentrate). Early treatment can prevent progression to life‑threatening laryngeal edema.
Common triggers include physical trauma (e.g., dental work, surgery), emotional stress, hormonal changes, and certain medications such as ACE inhibitors or estrogen‑containing drugs. Avoiding unnecessary invasive procedures, using protective gear during sports, managing stress through relaxation techniques, and reviewing medications with a clinician can reduce the likelihood of an attack.
n emergency kit should include a self‑injectable C1‑INH concentrate (e.g., Berinert or Cinryze), a bradykinin receptor antagonist (e.g., Icatibant), and an oral kallikrein inhibitor (e.g., Ecallantide) if approved in your region. It should also contain a written action plan, contact numbers for your allergist or immunologist, and a list of known triggers. Replace medications before their expiration dates and review the kit annually or after any changes in treatment.===
Type I HAE has low levels of functional C1‑INH, Type II has normal or elevated levels of a dysfunctional C1‑INH, and the “normal C1‑INH” form involves other genetic variants such as F12 mutations. Treatment differs: Type I/II patients often receive C1‑INH replacement or kallikrein inhibitors, while patients with normal C1‑INH may respond better to bradykinin receptor antagonists or specific factor XII inhibitors. A precise diagnosis guides the most effective acute and long‑term therapy.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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