Angioedema is swelling that is similar to hives, but the swelling is under the skin instead of on the surface.
Hives are often called welts. They are a surface swelling. It is possible to have angioedema without hives.
Angioedema may be caused by an allergic reaction. During the reaction, histamine and other chemicals are released into the bloodstream. The body releases histamine when the immune system detects a foreign substance called an allergen.
In most cases, the cause of angioedema is never found.
The following may cause angioedema:
Hives and angioedema may also occur after infections or with other illnesses (including autoimmune disorders such as lupus, and leukemia and lymphoma).
A form of angioedema runs in families and has different triggers, complications, and treatments. This is called hereditary angioedema.
The main symptom is sudden swelling below the skin surface. Welts or swelling on the surface of the skin can also develop.
The swelling usually occurs around the eyes and lips. It may also be found on the hands, feet, and throat. The swelling may form a line or be more spread out.
The welts are painful and may be itchy. This is known as hives (urticaria). They turn pale and swell if irritated. The deeper swelling of angioedema may also be painful.
Other symptoms may include:
The health care provider will look at your skin and ask if you have been exposed to any irritating substances. If your throat is affected, a physical exam might reveal abnormal sounds (stridor) when you breathe in.
Blood tests or allergy testing may be ordered.
Mild symptoms may not need treatment. Moderate to severe symptoms may need to be treated. Breathing difficulty is an emergency condition.
People with angioedema should:
Cool compresses or soaks can relieve pain.
Medicines used to treat angioedema include:
If the person has trouble breathing, seek medical help right away. A severe, life-threatening airway blockage may occur if the throat swells.
Angioedema that does not affect the breathing may be uncomfortable. It is usually harmless and goes away in a few days.
Call your provider if:
Go to the emergency room or call the local emergency number (such as 911) if there are any of the following symptoms:
Reviewed By: Stuart I. Henochowicz, MD, FACP, Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.