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.
Causes[change | change source]
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:
- Animal dander (scales of shed skin)
- Exposure to water, sunlight, cold or heat
- Foods (such as berries, shellfish, fish, nuts, eggs, and milk)
- Insect bites
- Medicines (drug allergy) such as antibiotics (penicillin and sulfa drugs), Non-steroidal anti-inflammatory drugs (NSAIDs), and blood pressure medicines (ACE inhibitors)
A form of angioedema happens in families and has different triggers, complications, and treatments. This is called hereditary angioedema.