What is Angioedema?
[[File:Angioedema2010.JPG|thumb|Child with angioedema, causing swelling in the face]] '''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== Angioedema may be caused by an [[allergy|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 drug]]s (NSAIDs), and [[blood pressure]] medicines (ACE inhibitors) * [[Pollen]] Hives and angioedema may also occur after infections or with other illnesses (including autoimmune disorders such as [[lupus]], [[leukemia]], and [[lymphoma]]). A form of angioedema happens in families and has different triggers, complications, and treatments. This is called hereditary angioedema. [[Category:Allergies]]