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Angioedema (Giant Hives)

What is angioedema?

Angioedema is a form of severe swelling beneath the skin’s surface. In some cases, the swelling occurs along with the appearance of hives. This is why angioedema is sometimes referred to as "giant hives." Hives are itchy, red welts that develop on the surface of the skin.

Both angioedema and hives are typically caused by an allergic reaction to food or medication. Other substances, such as pollen, pet dander, and insect bites, may also trigger angioedema. In very rare cases, the swelling can be a symptom of a more serious health condition, such as Hodgkin’s disease. Some areas of the body, such as the face and limbs, are more prone to swelling than others.

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, symptoms, treatments, and complications than acquired angioedema.

Angioedema generally isn’t a serious medical condition and doesn’t leave any lasting marks. It usually goes away on its own, even without treatment.

What are the symptoms of angioedema?

The most common symptom of angioedema is swelling beneath the surface of the skin. It may occur on the feet, hands, eyes, and lips. In more severe cases, the swelling can spread to other parts of the body. Angioedema may or may not be accompanied by swelling and welts on the surface of the skin.

Additional symptoms of angioedema may include stomach cramping and discolored patches or rash on the hands, arms, and feet. In rare cases, people with angioedema may experience a swollen throat, hoarseness, and difficulty breathing.

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

What causes angioedema?

Angioedema is typically the result of an allergic reaction. When you have an allergic reaction, your body produces histamine, which makes your blood vessels swell.

The following allergens can trigger angioedema:

  • insect bites
  • pollen
  • poison oak or ivy
  • latex
  • animal dander
  • medication
  • certain types of foods

Angioedema may also develop as a result of an infection or illness, such as lupus or leukemia. Hereditary angioedema occurs in people with a family history of the condition.

Who is at risk for angioedema?

Certain factors can increase your risk of developing angioedema. These include:

  • a previous occurrence of angioedema or hives
  • a previous allergic reaction
  • a family history of angioedema or hives
  • sudden temperature changes
  • stress or anxiety
  • injury

How is angioedema diagnosed?

Your doctor will perform a physical exam and ask you about your symptoms and past medical history. During the exam, your doctor will examine your areas of swelling and your welts, if any are present. They may also listen to your breathing to see if your throat has been affected. It’s important to tell your doctor if you’ve recently been exposed to certain substances that have previously triggered an allergic reaction in you. This may help your doctor determine the specific cause of your reaction.

Your doctor will perform a series of blood tests if hereditary angioedema is suspected. These may include:

These tests measure the levels of certain proteins in the blood. Low levels can indicate a health problem related to inflammation and swelling.

How is angioedema treated?

People with mild symptoms of angioedema may not need treatment. However, those with moderate or severe symptoms may require certain medications to help relieve intense itching and swelling. These medicines can include:

Certain home remedies may also help relieve symptoms. These include:

  • applying cool, wet compresses to help soothe the skin and prevent scratching
  • wearing loose cotton clothing to avoid further skin irritation

What is the long-term outlook for someone with angioedema?

In most cases, angioedema is a harmless condition that will disappear within one to three days. However, angioedema can be dangerous when the swelling occurs near the throat. A swollen throat or tongue can block your airway and make it very difficult to breathe. Severe angioedema may also cause anaphylaxis, a life-threatening allergic reaction. In such severe cases, emergency treatment is needed.

How do I prevent angioedema?

The best way to prevent angioedema is to avoid known and suspected allergens. You should also try not to irritate areas on the body that have been previously affected. Taking these preventive measures can help lower your risk of having another episode in the future.

Content licensed from:

Written by: the Healthline Editorial Team
Medically reviewed on: Apr 25, 2017: Justin Choi, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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