Angioedema is deep swelling that occurs when fluid builds up under your skin or mucus membranes. It may affect your face, throat, gastrointestinal tract, or other parts of your body.

Angioedema may result from taking certain medications, such as angiotensin converting enzyme (ACE) inhibitors.

It may also be caused by certain health conditions, such as:

  • Immunoglobulin E (IgE)-mediated allergy
  • chronic urticaria (CU)
  • hereditary angioedema (HAE)
  • viral or bacterial infections
  • autoimmune disorders
  • eosinophilic disorders, which affect several white blood cells

Read on to learn more about potential causes of angioedema.

Angioedema is a potential side effect of ACE inhibitors, which are medications for treating high blood pressure and certain types of heart disease.

African Americans have an increased risk of ACE inhibitor angioedema. This may be due to naturally lower bradykinin levels and, therefore, increased sensitivity to ACE inhibitor-mediated increases in bradykinin. Bradykinin is a molecule that plays a role in both inflammation and pain.

Angioedema may also develop as a side effect of other medications, such as:

  • nonsteroidal anti-inflammatory drugs (NSAIDs)
  • calcium channel blockers
  • fibrinolytic agents
  • muscle relaxants
  • opiates

Let your doctor know if you think you may be having side effects from any medication you’re taking.

Angioedema is a common symptom of anaphylaxis, which is a severe allergic reaction.

Anaphylaxis may develop in people with IgE-mediated allergy to certain foods, insect stings, or other triggers. An IgE-mediated allergy happens when IgE antibodies in the immune system mistakenly attack the allergen as a threat. Some individuals have exercise-induced anaphylaxis that develops after intense physical activity.

Other potential symptoms of anaphylaxis include:

  • hives
  • itching
  • skin flushing
  • hoarseness
  • wheezing
  • shortness of breath
  • abdominal pain
  • vomiting
  • fainting

Anaphylaxis is a medical emergency that requires immediate treatment with epinephrine.

CU is a condition that involves itchy hives and sometimes angioedema. People with CU have symptoms across a period of 6 weeks or longer, and symptoms may come and go or persist continuously.

Some people have chronic spontaneous urticaria (CSU), which occurs when CU symptoms develop without an identifiable trigger.

Some have chronic inducible urticaria (CIndU), which occurs when CU symptoms develop after exposure to certain triggers. Common triggers include:

  • friction or pressure on your skin
  • exposure to heat or cold
  • spicy foods
  • exercise
  • stress

It’s possible to have a combination of spontaneous and inducible symptoms.

HAE is a rare condition caused by genetic changes that may pass from parents to children or occur spontaneously. Roughly 25% of people with HAE have no family history of it.

HAE affects C1-inhibitor, a protein that helps control inflammation. While some people with HAE don’t make enough C1-inhibitor, others have typical levels, but the protein doesn’t work properly. Very rare cases of HAE involve typical C1-inhibitor levels and function.

Common HAE symptoms include skin swelling and abdominal pain, which typically last 2 to 5 days.

Throat swelling happens in rare cases and requires emergency treatment.

Other health conditions may cause changes in your immune system that can lead to angioedema.

Examples include:

  • viral or bacterial infections
  • lymphoproliferative disorders, such as:
    • monoclonal gammopathy of unknown significance (MGUS)
    • lymphocytic leukemia
    • B-cell lymphoma
  • autoimmune disorders, such as:
    • ulcerative colitis (UC)
    • systemic lupus erythematosus
    • Sjögren disease
  • eosinophilic disorders, such as Gleich syndrome

Some people develop idiopathic angioedema, which has no identified cause.

Your treatment options and outlook for angioedema depend on what’s causing it.

Your doctor may order tests or refer you to a specialist to learn what’s causing angioedema. They may prescribe medication to prevent or treat symptoms. If certain activities or exposures seem to trigger angioedema, they can help you learn how to avoid those triggers.

Contact emergency medical services (EMS) or go to the emergency department if you develop signs or symptoms of angioedema in your upper airway, including swelling of your throat or tongue. Angioedema in your upper airway can cause life threatening breathing difficulties and requires quick treatment.

Angioedema is deep swelling under your skin or mucosal membranes.

Taking certain medications, such as angiotensin converting enzyme (ACE) inhibitors, may trigger angioedema. Your doctor may recommend changes to your medication if you develop angioedema or other treatment side effects.

Certain health conditions may also cause angioedema. These include IgE-mediated allergy to food, insect stings, or other triggers. Angioedema may be a sign of a life threatening allergic reaction that requires immediate treatment.

Other potential causes include:

  • CU
  • HAE
  • viral or bacterial infections
  • lymphoproliferative disorders
  • autoimmune disorders
  • eosinophilic disorders

Your doctor may order tests or refer you to a specialist to learn what’s causing angioedema and recommend treatment. Some people develop idiopathic angioedema, which has no identifiable cause.

Contact EMS or go to the emergency department if you develop signs or symptoms of angioedema in your upper airway. Severe swelling of your throat or tongue may cause life threatening breathing difficulties.