Angioneurotic edema; Welts; Allergic reaction - angioedema; Hives - angioedema
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:
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:
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:
Dreskin SC. Urticaria and angioedema. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 252.
Habif TP. Urticaria, angioedema, and pruritus. In: Habif TP, ed. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 6th ed. Philadelphia, PA: Elsevier Mosby; 2016:chap 6.
Tran TP, Muelleman RL. Allergy, hypersensitivity, angioedema, and anaphylaxis. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 119.
Last reviewed on: 3/20/2016
Reviewed by: Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.