Angioedema is swelling that occurs deep within the skin or around mucous membranes. It’s often due to allergens or reactions to medications, though the cause may also be unknown.

Angioedema is a temporary, recurring subcutaneous (under the skin) or submucosal (thin layer of tissue under mucous membrane) swelling. It typically affects the:

  • skin on the forehead, around the eyes, and on the lips
  • tongue
  • hands
  • feet
  • genitals
  • gastrointestinal tract
  • upper airways

The direct cause of the swelling is leaking blood vessels in the surrounding tissues or skin, but there are several potential underlying causes of the condition.

In some cases, swelling occurs along with the appearance of hives. This is why angioedema is sometimes referred to as “giant hives.”

Hives are itchy and raised welts that develop on the skin’s surface, involving the top two skin layers.

Causes of either angioedema or hives include:

  • allergic reaction or intolerance to food
  • side effect or allergy to a medication
  • allergens in the surrounding environment, such as:
    • pollen
    • pet dander
    • venom from insect bites

In other cases, a doctor may not know the underlying cause.

When angioedema is passed from a parent to a child through genetic transmission, the condition is known as hereditary angioedema. Hereditary angioedema has different causes than acquired angioedema, but the symptoms and treatment approaches are similar.

how angioedema may present on darker skinShare on Pinterest
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The most common symptom of angioedema is swelling. It often occurs around the eyes, lips, and tongue, but it may also occur in the feet, hands, or genitals.

Angioedema may be accompanied by swelling and welts on the skin’s surface known as urticaria (hives). Allergic angioedema can cause itchiness.

Other angioedema symptoms may include:

  • fainting
  • abdominal cramping
  • dizziness
  • shortness of breath
Medical emergency

In more severe cases, people with angioedema may experience swelling of the airways, making it difficult to breathe, and an unsafe drop in blood pressure.

Call 911 or go to an emergency room right away if you’re having trouble breathing. This may be a sign of a medical condition that requires prompt treatment.

There are several types and causes of angioedema.

Allergic angioedema

Allergic angioedema is the most common form of angioedema. It may occur due to reactions to food, medication, or other allergies.

Some potential causes include:

  • latex
  • peanuts
  • insect stings
  • antibiotics
  • shellfish
  • insect bites

Nonallergic drug-induced angioedema

Drug-induced angioedema occurs when a person has a nonallergic reaction to medication. You can distinguish it from allergic reactions due to the lack of hives or itchiness.

Drug-induced angioedema is the second most common type of angioedema.

A common cause includes angiotensin converting enzyme inhibitors, a common blood pressure medication.

Hereditary angioedema (HAE)

Hereditary angioedema (HAE) is less common than either allergic or drug-induced angioedema. It occurs when you inherit a deficiency or defect in an enzyme in the complement pathway, which makes up part of the immune system.

Idiopathic angioedema

Idiopathic angioedema occurs when a doctor cannot find a cause for the angioedema. Idiopathic cases of angioedema may occur in up to 40% of cases. Experts do not know much about how idiopathic angioedema starts or its nature.

Acquired angioedema

Acquired angioedema may develop after an infection or illness, such as lupus (SLE). In rare cases, it may be the result of leukemia or lymphoma. Autoimmune diseases can also cause this type of angioedema.

Certain factors may increase your risk of developing angioedema. Risk factors can vary based on the severity or cause. According to older research from 2014, potential risk factors associated with recurrent and severe angioedema include:

  • older age
  • being of Hispanic descent
  • having ACEi-induced angioedema
  • having coexistent cardiopulmonary disease
  • smoking

Another study from 2020 noted that people who take ACE inhibitors might have a higher chance of developing angioedema due to:

  • being born female
  • being of African American descent
  • taking NSAIDs
  • living in the upper Midwest

If you have allergies, try to avoid known triggers because these may cause angioedema. Other risk factors may include:

  • previous occurrence of angioedema or hives
  • previous allergic reaction
  • family history of angioedema or hives
  • sudden temperature changes
  • stress or anxiety
  • certain medical conditions

A doctor will perform a physical exam and ask you about your symptoms and medical history. During the exam, they will examine your swelling and welts, if any are present. They may also listen to your breathing to see if your throat has been affected.

Be sure to tell your doctor if you’ve recently been exposed to substances that have triggered an allergic reaction. This information may help them determine the specific cause of your reaction.

Your doctor will perform blood tests if hereditary or acquired angioedema is suspected. These may include:

These tests measure the levels or function of certain proteins in the blood. Abnormal results can be associated with a health problem related to an underlying autoimmune disease. They can also help determine the best course of treatment.

People with mild symptoms of angioedema may not need treatment. But those with moderate or severe symptoms may require medications to relieve intense swelling. Medications can include:

  • epinephrine (EpiPen) in the case of an acute allergic reaction
  • antihistamines like loratadine (Claritin, Alavert) and cetirizine (Benadryl Allergy, Piriteze Allergy, Zirtek Allergy, more) in the case of an allergic reaction or angioedema when the cause is unknown
  • glucocorticosteroids like prednisone or Solu-Medrol in the case of an acute allergic reaction

Hereditary angioedema may require surgical intervention or intubation. They may also treat a person with:

  • C1 inhibitor concentrate
  • ecallantide (Kallikrein inhibitor)
  • icatibant (bradykinin-receptor antagonist)

If possible, avoid contact with substances that may cause swelling. In less severe cases of angioedema, applying cool, wet compresses to soothe the skin and prevent scratching and wearing loose cotton clothing to avoid further skin irritation may help.

If a medication is causing the angioedema, your doctor may have you switch to a different one.

If you’re pregnant, you should speak with your doctor before starting any medication or before treatment.

Long-term treatment for recurrent angioedema may involve using C1 inhibitors.

In many cases, angioedema is a harmless condition that will disappear within 1 to 2 days.

However, angioedema can be dangerous when severe swelling occurs near the throat. A swollen throat or tongue can block your airway and make breathing difficult.

Severe angioedema may be due to anaphylaxis, a sudden life threatening reaction. In such severe cases, you should get emergency medical help immediately.

The best way to prevent allergic angioedema is to avoid known and suspected allergens or those that have caused the condition to occur previously.

Taking these preventive measures can help lower your risk of having another episode.

Angioedema symptoms can range from mild to life threatening, so you may need emergency medical care, especially if you have trouble breathing.

When treatment is needed, doctors will often recommend antihistamines or other medications to help the swelling go down. Mild cases may not need treatment and can clear within a few days.