Angioedema is swelling that occurs below the skin's surface. The swelling, which can be sudden and severe, typically affects soft tissues, such as the eyelids, lips, tongue, throat and genitals. In some cases, the hands and feet may be affected. 
Though angioedema is not a form of hives, it often occurs at the same time as hives. 
Types of angioedema
According to the <a href="http://www.netreturns.biz/healthinfo/bouncelink.aspx?shortcut=aaallergy" target="_blank">American Academy of Allergy, Asthma &amp; Immunology</a>, there are several categories of angioedema: 
Acute angioedema. This condition lasts only a short time (minutes to days). It's typically caused by an allergic reaction to foods (like seafood, nuts or strawberries) or medications. 
Chronic angioedema. This condition recurs over a long period of time. It typically doesn't have an identifiable cause. 
Hereditary angioedema (HAE). This is a rare, genetic form of the condition. It affects about 6,000 to 10,000 people in the United States and often begins in childhood, according to the <a href="http://www.netreturns.biz/healthinfo/bouncelink.aspx?shortcut=fda" target="_blank">U.S. Food and Drug Administration</a> and the <a href="http://www.netreturns.biz/healthinfo/bouncelink.aspx?shortcut=nih" target="_blank">National Institutes of Health</a>.
HAE causes recurring swelling that's unrelated to allergies. Arms, legs, hands and feet are common targets, but swelling can affect other parts of the body, including the gastrointestinal tract, where it can cause severe pain. 
HAE is most dangerous when it affects the tongue or throat because sudden swelling can block the airway. 
HAE is often a lifelong condition. Attacks often occur for no apparent reason, though some research shows they may be triggered by stress, infection or minor trauma. 
Treatment
When angioedema is caused by allergies, a corticosteroid or antihistamine can help. 
Severe bouts may require an injection of epinephrine. Anyone who has trouble breathing or swallowing needs to see a doctor right away. 
These medicines don&rsquo;t work well for people with HAE. Other drugs, though, can help during an HAE attack and help prevent or reduce the severity of future ones. 
Getting help
If you're having symptoms of angioedema&mdash;or any type of skin problem&mdash;talk with your doctor. He or she may direct you to an allergist, who can help determine exactly what is causing your skin condition and what might be done to get it under control. 
Reviewed 7/17/2023

Understanding angioedema

Angioedema, whether caused by allergy or genetics, is a potentially serious condition. But treatments are available that can help keep it under control.