Causes of angioedema

Angioedema Swelling under the surface of the skin. It occurs when fluid leaks from blood vessels into nearby subcutaneous tissue and mucous membranes, such as the mucous membranes inside the nose or genitals.

There are several types of angioedema, each with different causes. The most common is an allergic reaction to something in the environment. Certain medications, infections, and diseases can also cause angioedema.

Some people have a condition called hereditary angioedema (HAE), which has a genetic component.

This article looks at the various types of angioedema and what causes each type of angioedema. It explains what happens in the body when swelling occurs and describes the various triggers for this response.

Angioedema is different from hives or hives, which are swellings on the surface of the skin, not the tissue beneath it. Angioedema can occur with urticaria.

Common causes

Angioedema can be triggered by exposure to a variety of substances, from common allergens to prescription drugs. It can also be a symptom or side effect of certain diseases or medical procedures.

There are two types of angioedema—one that occurs when the immune system releases histamine, and the other that occurs when the body releases a peptide called bradykinin, which regulates many important bodily functions.


Most of the time, angioedema occurs when the immune system mistaken otherwise harmless substances as harmful to the body. In defense, it releases a chemical called histamine into the bloodstream.

Histamine causes tiny blood vessels to leak fluid into nearby subcutaneous tissue. This is why this type of angioedema is called histaminergic. Most histaminergic angioedema is itchy and accompanied by hives; more rarely, it can occur alone.

Allergens may be triggers for such reactions. The most common allergens associated with angioedema include:

  • emulsion
  • Pet dander (tiny patches of skin shed by animals with fur or feathers)
  • pollen
  • Foods – especially dairy, eggs, fish and shellfish, tree nuts, peanuts, soy, and wheat
  • insect bites or bites
  • certain drugs
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There are some less obvious causes of histaminergic angioedema. Some people experience swelling when exposed to extreme heat or cold, sunlight, or vibration—for example, while using a lawn mower, riding in a bumpy vehicle, or even wiping themselves with a towel after a shower.


Nonhistaminergic angioedema is swelling that does not involve histamine. Instead, it is caused by the release of a peptide called is usually called bradykinesia angioedema.

These substances play many roles in the body. One is to dilate (enlarge) blood vessels. This is important for some bodily functions, such as keeping blood pressure at normal levels.

If bradykinins are released when they are not needed, their effect on blood vessels can cause them to seep into surrounding tissue and cause swelling. In most cases, the legs, arms, genitals, face, lips, throat, and gastrointestinal (GI) tract are affected.

ACE inhibitors, which are used to treat hypertension, heart attack, failure, and kidney disease, are a common cause of drug-induced nonhistaminergic angioedema.

Sometimes the cause of angioedema is not known, which means it is “idiopathic.” In most cases, the face, mouth, and tongue are affected. About 52% of people who experienced idiopathic angioedema went to the emergency room at least once, and 55% were treated with high-dose corticosteroids to reduce swelling.


Angioedema is swelling under the skin that occurs when fluid leaks from blood vessels. This happens when the body releases histamine or bradykinin, which causes fluid to leak from blood vessels into nearby tissues. Triggers range from common allergens to certain medications, diseases and medical procedures.


Some people who experience bradykinetic angioedema have genetic mutations that make them susceptible to triggers. This is called hereditary angioedema and is an autosomal dominant disorder, which means you only need to inherit the responsible gene from one parent.

There are three types of HAE.Two are caused by genetic mutations SERPIN1 Gene.The cause of the third type of HAE is unknown, but a small percentage of these patients are thought to be caused by F12 Gene.

Genetics may also be a factor in vibratory angioedema. Autosomal dominant vibratory urticaria is associated with mutations in the ADGRE2 gene that make mast cells more likely to release histamine.

HAEs are rare, occurring in 1 in 50,000 people, and are usually only suspected in people with angioedema who do not respond to antihistamines or have a family history of angioedema.


Angioedema is swelling of the tissue under the skin. This happens when histamine (an immune system chemical) or a peptide called bradykinin is mistakenly released into the bloodstream, causing fluid to leak from the blood vessels.

This happens for a variety of reasons, from exposure to allergens that trigger histamine to certain medications or medical conditions or procedures that trigger bradykinin. The tendency to develop angioedema can also be inherited.

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If you or someone else experiences sudden swelling or any symptoms of angioedema, you should seek medical attention. Angioedema affecting the gastrointestinal tract can cause severe vomiting, severe pain, and dehydration.

When swelling affects the face, mouth, tongue, throat, or throat, it restricts air flow to the lungs and is a medical emergency.

Frequently Asked Questions

  • What causes angioedema?

    Angioedema is triggered by increases in histamine and/or bradykinin, which stimulate a cascade of inflammatory responses that lead to dilation of blood vessels and infiltration of fluid into underlying tissues. When this occurs in the deeper subcutaneous and submucosal tissues, it results in angioedema.

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  • What is Hereditary Angioedema?

    Hereditary angioedema is a genetic disorder that is often characterized by an insufficient amount or function of C1 inhibitors, the substances the body uses to regulate a peptide called bradykinin. In rare cases, hereditary angioedema may be associated with normal amounts and function of C1 inhibitors. Like histamine, bradykinin induces vasodilation. Without a C1 inhibitor to moderate the response, the accumulation of bradykinin can trigger excessive tissue swelling.

  • Is Angioedema Autoimmune?

    Chronic and recurrent angioedema is often associated with autoimmune diseases such as lupus and Hashimoto’s thyroiditis. Some studies suggest that as many as 30% to 50% of idiopathic angioedema (ie, angioedema of unknown origin) may be associated with some form of autoimmune disease. In this condition, itchy hives (hives) are often accompanied by deeper tissue swelling.

  • How does stress cause angioedema?

    Stress angioedema occurs when steady pressure applied to an area of ​​skin causes immediate or delayed swelling of deep tissue. It is thought to be autoimmune in nature, such as wearing tight clothing or sitting for long periods of time, during which sustained stress can cause mast cells in vascular tissue to rupture and release histamine. Extreme vibration can do the same.

  • Which drugs are most likely to cause angioedema?

    Angioedema may occur with exposure to certain drugs:

    ACE inhibitors, such as Vasotec (enalapril) and Prinivil (lisinopril), can cause the accumulation of bradykinin by preventing the breakdown of bradykinin

How to Diagnose Angioedema

Whatever the cause, gastrointestinal angioedema can lead to severe vomiting, severe pain, and dehydration. When swelling affects the face, mouth, tongue, throat, or throat, it restricts air flow to the lungs and is a medical emergency.