Angioedema

Definition

Angioedema is a swelling similar to hives, but the swelling is beneath the skin rather than on the surface. The swellings are called welts.

See also: Hereditary angioedema

Alternative Names

Causes

Angioedema may be caused by an allergic 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.

Sometimes the cause of angioedema is never found.

The following items may cause angioedema.

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

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

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.

References

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

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

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