Angioedema (Welts)

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

Angioneurotic edema; Welts

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.