Angioedema: Overview and More

Angioedema is swelling of the lower layer of tissue directly under the skin or mucous membranes, where fluid builds up and blood vessels dilate. The swelling primarily affects the face, tongue, lips , throat, hands, and feet, but it can become severe and even life-threatening if it occurs in the throat, lungs, or gastrointestinal tract.

Angioedema is often caused by allergies, but it can also be caused by non-allergic reactions to medications, infections, cancer, genetics, and even stress. Treatment depends on the underlying cause, but may include antihistamines, steroids, and prevention of known triggers.

Symptoms of angioedema

Although angioedema is closely related to hives ( urticaria ) in that they have the same underlying causes, the symptoms often differ.

Angioedema occurs in the subcutaneous tissue under the outermost layers of the skin (called the dermis and epidermis). Therefore, it causes a deeper general edema, which tends to last longer than hives.

In contrast, urticaria affects the epidermis and dermis and is characterized by raised blisters with well-defined boundaries.

With angioedema, swelling can start in minutes or develop in hours. Depending on the cause, the inflamed skin area may itch or cause a burning, tingling, or numbness sensation.

The swelling can last for hours or days. When the swelling is completely healed, the skin usually appears normal, with no flaking, peeling, scarring, or bruising.

An example of angioedema. Saevich Mikalai / Getty Images

Some types of angioedema can be much more serious, especially if they extend beyond the extremities, face, or trunk. Among the complications:

  • Angioedema of the gastrointestinal tract can cause severe vomiting, severe mid-abdominal pain, and dehydration (due to the inability to retain fluids) .
  • Angioedema of the lungs can cause wheezing, shortness of breath, and airway obstruction.
  • Angioedema of the larynx (larynx) can cause suffocation and death.

Causes

Generally speaking, Quincke's edema is caused by an abnormal immune system response in which chemicals known as histamine or bradykinins enter the bloodstream .

Histamine , which is part of the immune defense, causes blood vessels to dilate so that immune cells can move closer to the site of injury. Bradykinins also cause blood vessels to dilate, but they do so to regulate bodily functions such as blood pressure and breathing. When released abnormally, alone or together, these compounds can cause swelling, which we call angioedema.

Hereditary angioedema

Hereditary angioedema (HAE) is usually an autosomal dominant disorder, which means that you can only inherit the problem gene from one parent. Genetic mutations generally result in an overproduction of bradykinins and can affect all organ systems, including the skin, lungs, heart, and gastrointestinal tract.

Although stress or trauma can be the cause of HAE, the cause of most seizures is unknown. Relapses are common and can last two to five days. ACE inhibitors and estrogen-based contraceptives , which can affect bradykinin levels, are known to increase the frequency and severity of attacks.

HAO is rare, occurring in only one in 50,000 people. and is most often suspected when antihistamines or corticosteroids fail to relieve symptoms.

Diagnostics

Angioedema can often be diagnosed based on its clinical presentation, as well as your medical history and accompanying symptoms.

If an allergy is suspected, your healthcare provider may suggest that you have an allergy test to determine the causative trigger (allergen). This may include a skin injection (in which a small amount of a suspected allergen is injected under the skin), a patch test (using a sticky patch soaked in the allergen), or blood tests to check if your blood contains allergic antibodies. …

Blood tests can also be used to diagnose HAE. If all other causes of angioedema have been ruled out, your healthcare provider may decide to test the level of a substance called C1 esterase inhibitor , which regulates bradykinins , in your blood. People with HAE are less able to produce this protein, so a low level of C1 esterase inhibitor is considered a strong sign of this type of angioedema.

Watch out

One of the best ways to prevent future attacks is to avoid any known triggers. If this is not possible, the treatment will seek to soften the immune response to reduce the levels of histamine or bradykinins in the blood.

Among the options:

  • Oral antihistamines are generally prescribed to treat angioedema associated with allergies.
  • In some cases, systemic corticosteroids respond well to treatment, depending on the cause. Prednisone is one of the most commonly prescribed options, but it is only used for short-term relief due to the risk of side effects .
  • HAO can be treated with Calbitor (ekallantid) or Firazyr (ikatibant). Calibor blocks the enzymes that stimulate bradykinin production, while Firazyr prevents bradykinins from attaching to receptors on target cells. Common side effects include nausea, fatigue, headache, and diarrhea.
  • People with HAO can also find relief by taking androgens (male hormones) such as methyltestosterone and danazol. They work by suppressing the levels of bradykinins circulating in the blood. Long-term use can cause masculinizing effects in women (including male pattern baldness and facial hair) and breast enlargement (gynecomastia) in men.
  • Severe laryngeal angioedema should be treated with an emergency injection of epinephrine (epinephrine). People with known severe allergies often need to have a pre-filled epinephrine injector, called an EpiPen , with them in case of an attack.

Verywell's Word

Angioedema can be troublesome, especially if the swelling is severe or recurring. Even if there are no other visible symptoms, you should see your doctor if the swelling persists for more than a couple of days.

If angioedema is thought to be related to an allergy, but you don't know the cause, keep a diary to record the foods you eat or the environmental allergens you may have been exposed to. This can help narrow your search and avoid troublesome triggers.

On the other hand, if you have a sore throat with some difficulty breathing, call 911 or have someone take you to the nearest emergency room.

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