Angioedema is a swelling similar to urticaria (hives), but the swelling is beneath the skin rather than on the surface. The swellings are called welts. The welts usually occur around the eyes and lips. They may also be found on the hands, feet, and throat. Angioedema can result from certain allergies.

See also: Hereditary angioedema

Angioedema is usually the result of an allergic (hypersensitivity) reaction. It is associated with the release of histamine and other chemicals into the bloodstream. The body releases histamine when the immune system detects a foreign substance called an allergen.

The following items may cause angioedema.

• Medications
• Foods (such as berries, shellfish, fish, nuts, eggs, milk, and others)
• Pollen
• Animal dander (scales of shed skin)
• Insect bites
• Exposure to water, sunlight, cold or heat
• Emotional stress

Hives and angioedema may also occur after infections or illness (including autoimmune disorders, leukemia, and others).

There is a form of angioedema that runs in families and has different triggers, complications, and treatments. This is called hereditary angioedema, and is not discussed here.

• Sudden development of red welts
  • Welts are usually on the eyes and mouth, but may be on the hands, feet, or in the throat
  • Welts are itchy or painful
  • Turn pale and swell if irritated
• Swollen eyes and mouth
• Abdominal cramping
• Difficulty breathing
• Chemosis (swollen lining of the eyes)

The doctor will look at your skin and ask you if you have been exposed to any irritating substances. A physical exam might show stridor (crowing sound when inhaling) if the throat is affected.

Rarely, allergy testing may be performed to determine the causative allergen.

Mild symptoms may not need treatment. Moderate to severe symptoms may need treatment. Breathing difficult or stridor is an emergency condition.

Cool compresses or soaks can provide pain relief.

Medications include

• antihistamines
• adrenaline (epinephrine)
• terbutaline (a bronchodilator)
• cimetidine (Tagamet)
• corticosteroids
• sedatives
• tranquilizers

If the person has trouble breathing, seek immediate medical help. (See breathing difficulties - first aid. )

At the hospital, a tube may be placed in the throat to keep the airway open.

Angioedema that does not affect the breathing may be uncomfortable, but is usually harmless and goes away in a few days.

• Life-threatening airway obstruction (if swelling occurs in the throat)
• Anaphylactic reaction

Call your health care provider if you have never had angioedema before, if it is severe, or does not respond to treatment.

Go to the emergency room or call the local emergency number (such as 911) if difficulty breathing, wheezing, stridor, or fainting occurs with an episode of angioedema.

To prevent angioedema from coming back, you should avoid irritating the affected area, stay away from known allergens, and avoid temperature extremes.

Never take medications that are not prescribed for you.

Kaplan AP. Angioedema. J Am Acad Dermatol. Sept 2005; 53(3): 373-88.

Habif TP. Clinical Dermatology. 4th ed. St. Louis, Mo: Mosby, Inc. 2004:129.

Marx J. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th ed. St. Louis, Mo: Mosby; 2002:1623.