Understanding Angioedema

Allergic angioedema. Note that this child is unable to open his eyes due to swelling.
Allergic angioedema. Note that this child is unable to open his eyes due to swelling. Wikimedia Commons

Swelling of the neck, tongue, lips, throat, and the area around the eyes is often caused by angioedema. Angioedema is caused by the release of histamine into the skin by allergic cells such as mast cells. This is the same process that causes urticaria, or hives, but angioedema occurs in deeper skin tissues such as the lips, tongue, throat, the area around the eyes, hands, feet, and genitals.

Angioedema does not make the skin red, normally it is not itchy, and it most often involves swelling of only one side of the face at a time.

Many people describe the symptoms of angioedema as tingling, numbness or a burning sensation, like you may feel after going to the dentist. The swelling of angioedema typically lasts for many hours, and once the swelling has gone away, the skin appears completely normal—there is not typically any bruising, flaking, peeling or scar formation.

What Are the Causes of Angioedema?

Often, the causes of angioedema are the same as the causes of urticaria: histamine release from allergic cells. Approximately half of people with these symptoms experience both urticaria and angioedema; 40 percent experience only urticaria, and 10 percent experience only angioedema.

Angioedema may be a sign of an allergic reaction, especially to medicines, foods, or insect stings. However, when symptoms become chronic (greater than 6 weeks), the cause is more likely to not be caused by allergies. Chronic angioedema may be caused by an autoimmune disease, thyroid disease, parasitic infections, alcohol use, non-steroidal anti-inflammatory medicines (NSAIDs), ACE inhibitors (a common blood pressure medicine), and hereditary angioedema.

When food allergies are the cause, you can often tell what the trigger is, because most reactions to foods occur within 20-30 minutes of eating the food. Medications may not be as obvious as a cause, except when a new medication is started and symptoms occur. NSAIDs and ACE inhibitors are well-known causes of angioedema, although any medication has the potential to cause the symptom.

What Types of Diseases Can Mimic Angioedema?

There are a number of causes of swelling of the lips, eyes and face that are not angioedema, although they may be incorrectly diagnosed as such. These causes of pseudo-angioedema may include contact dermatitis, autoimmune diseases such as dermatomyositis, parasitic infections such as trichinosis, low thyroid function, and swelling and redness of the entire face from superior vena cava (SVC) syndrome.

The differences between these causes of true angioedema and pseudo-angioedema are as follows:

  • The swelling from contact dermatitis may involve the eyes and lips, but not the tongue and throat. The skin is usually red and itchy, and will often peel or flake when the swelling goes away.
  • The swelling associated with certain autoimmune diseases, such as dermatomyositis, will be present for days, weeks or months at a time, is usually red, and often will be associated with other symptoms such as extreme fatigue, weakness, fevers, weight loss and joint and muscle aches.
  • The swelling that results from severely low thyroid function is called myxedema, and often involves swelling around the eyes. The swelling is consistent rather than intermittent, and other symptoms of low thyroid function are also present.
  • The swelling of trichinosis should involve both eyes and is consistent rather than intermittent.
  • Swelling from SVC syndrome is due to blood having trouble draining back to the heart, so the swelling involves the entire face, neck, and upper chest, is red, is worse in the morning after lying down for many hours, and may get better once the person is standing up for a while. SVC syndrome is almost always associated with cancer.

What is the Treatment for Angioedema?

Treatment of angioedema involves removing the causative trigger or fixing the underlying medical condition, but also the use of various medications such as oral antihistamines and/or systemic corticosteroids.

These medications may take hours to days to work, and if symptoms recur frequently, the use of a daily antihistamine to prevent further episodes of angioedema is a good idea. People with episodes of facial angioedema (tongue, lips, throat) should carry an injectable form of epinephrine (such as an Epi-Pen), to use if the swelling is severe enough to affect the ability to breathe. If the Epi-Pen is needed, the person should seek emergency medical care right after using this emergency medicine.


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Practice Parameters for Disease Management: Acute and Chronic Urticaria and Angioedema. Ann Allergy. 2000; 85: S525-44.