Angioedema is a 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.
Angioneurotic edema; Welts
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:
A form of angioedema runs in families and has different triggers, complications, and treatments. This is called hereditary angioedema, and it is not discussed in this article.
The main symptom is sudden swelling below the skin surface. You may also develop welts or swelling on the surface of your skin.
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 (uticaria). 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 you if you have been exposed to any irritating substances. A physical exam might reveal abnormal sounds (stridor) when you breathe in if your throat is affected.
The health care provider may perform blood tests or allergy testing.
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 provide pain relief.
Medications used to treat angioedema include:
If the person has trouble breathing, seek immediate medical help. A severe, life-threatening airway blockage may occur if the throat swells.
Angioedema that does not affect the breathing may be uncomfortable, but is usually harmless and goes away in a few days.
Call your health care provider if:
Go to the emergency room or call the local emergency number (such as 911) if you have:
Dreskin SC. Urticaria and angioedema. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap 260.
Wasserman SI. Approach to the person with allergic or immunologic disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap 257.