Angioedema

Angioedema is swelling under your skin. The most common areas affected are your face, lips, tongue, throat and genitals.

Key points

  1. Angioedema is similar to hives, but hives are weal-like swellings on the surface of your skin. Angioedema involves swelling deeper in your tissues and the swelling may last longer.
  2. Around 1 in 3 of people who get hives will get angioedema as well. Having angioedema on its own (without hives) is much less common.
  3. Angioedema has several causes, and often the exact cause is unknown. It's often the result of an allergic reaction to certain foods, some medicines, insect bites or stings and latex.
  4. It is not normally serious, but it can be an ongoing problem for some people. Very rarely, it can be life-threatening if it affects your breathing.
  5. There is no known cure for angioedema. However, it may be possible to prevent swelling with medication. 


Image source: DermNet NZ

What is angioedema?

Angioedema involves swelling in the tissue under your skin. The most common areas affected are your face, lips, tongue, throat and genitals. Swelling in one area usually lasts between 1–3 days. Occasionally, swelling of internal organs like your oesophagus, (food pipe or gullet that leads to the stomach), stomach, or bowel can trigger chest or stomach pains.

What causes angioedema?

The release of histamine within your skin seems to be the trigger for swelling in most people. The most common triggers for this are ACE inhibitor medicines, hereditary angioedema (HAE), acquired C1-inhibitor deficiency, infection and allergy.

Allergies

Angioedema is often the result of an allergic reaction. This is where your body mistakes a harmless substance, such as a certain food, for something dangerous. It releases chemicals into your body to attack the substance, which causes swelling.

Angioedema can be triggered by an allergic reaction to:

Angioedema caused by allergies is known as allergic angioedema. Allergic disease is almost never the cause of swellings that last for days or recur for weeks at a time.

Medicines

Some medicines can cause angioedema – even if you're not allergic to the medicine. Most swellings appear within the first few months of starting the medicine but sometimes you may not have any reaction for months to years, or it may only happen when the dose is increased.

Medicines that can cause angioedema include:

Angioedema caused by medicine is known as drug-induced angioedema.

The swellings from these medications are not itchy or painful, usually occur around your face, tongue and throat and are not accompanied by hives. It can take a few weeks after stopping the medication for the swelling to go down. 

Hereditary angioedema (HAE)

Rarely, angioedema occurs because of a genetic fault that you inherit from your parents. These have low levels (deficiency) or reduced effectiveness of C1-inhibitor enzyme. How often the swelling occurs can vary. Some people experience it every week, while in others it may occur less than once a year.  If you have HAE, you have a 1 in 2 chance of passing it on to your children. Read about hereditary angioedema (HAE).  

Acquired C1-inhibitor deficiency

In even rarer cases, low levels of C1-inhibitor occur in association with some cases of lymphoma, malignancies and in autoimmune diseases such as systemic lupus erythematosus (SLE). 

Infection

A viral infection is the most common cause of hives and angioedema in children, especially if they last for more than 24 hours. 

Other causes

Thyroid gland disease and some types of inflammatory arthritis are more common in people with hives and angioedema. In some people whose swellings continue for years without an obvious cause, an autoimmune process may be responsible. This means that part of your body's immune system may be attacking your skin. 

In most cases, a single cause is not found. 

What are the symptoms of angioedema?

Swelling

The main symptom is swelling. It may be itchy, tingling or burning, but often there are no symptoms other than the discomfort of the swelling. Swelling caused by angioedema can develop suddenly or come on gradually over a few hours. It normally lasts a few days.

The most common areas of your body affected are your face, lips, tongue, throat and genitals. Sometimes the swelling can be painful, particularly when it occurs over your joints. These swellings can be large and may last for days.

Swelling in one area usually lasts between 1–3 days. Occasionally, swelling of internal organs like your oesophagus, (food pipe or gullet that leads to the stomach), stomach or bowel can trigger chest or stomach pains.

If swelling is constant rather than coming and going, other possible causes of swelling should be considered.

Rash

Often, the swelling occurs with a raised, itchy rash called urticaria (hives). The rash will usually settle in a few days. Otherwise, the skin over the swelling may feel tight and painful but look normal.

Other symptoms

Less common symptoms of angioedema include:

Is angioedema dangerous?

Angioedema does not damage your internal organs like your kidneys, liver or lungs. The only danger is if your throat or tongue swell severely, as this can cause difficulty breathing. Severe throat swelling requires early use of medication such as adrenaline for anaphylaxis and transfer to hospital by ambulance.

Swelling on the outside of your neck is uncomfortable but does not affect breathing. Swelling that interferes with breathing is uncommon, even in people with recurrent angioedema.

People with recurrent angioedema should be referred by their doctor to a clinical immunology/allergy specialist to investigate for an underlying cause and optimise treatment.

How is angioedema diagnosed?

If you have significant or repeating angioedema, your doctor will examine you and carry out blood tests. The main reason for testing is to exclude underlying diseases, which may appear as angioedema first, and other conditions later. These conditions might need separate treatment or investigation.

How is angioedema treated?

The treatment for angioedema depends on what's causing it.

There are several different types of angioedema, each of which has a different cause. Angioedema can usually be treated at home, although severe cases may need to be treated in hospital.

Your symptoms may disappear over time without any treatment. Some people only have a single episode, whereas others suffer from recurrent bouts, which eventually stop for no apparent reason.

Change medications

If a certain medicine you're taking is thought to be responsible for your angioedema, your doctor will usually advise stopping it. They can prescribe a different medicine for you to take instead. This is usually all that needs to be done. Tell your doctor if your symptoms continue or come back after switching medicine.

Avoid aggravating factors

Avoiding excessive heat, spicy foods or alcohol are often useful. Since aspirin can make swellings worse, it should be avoided unless already being taken without a problem.

Take antihistamines

Antihistamines block the effect of histamine which is usually the cause of the swelling. Since they take 1–2 hours to reduce symptoms, it is often better to take them regularly, rather than as needed. The aim is to stop the episodes of swelling or to make them less frequent or less severe.

If you have severe angioedema, it is often better to take them every day, stopping every month or two to see if they are needed, and restarting them if they are.

Different people respond best to different antihistamines. Non-drowsy antihistamines are available over the counter without prescription. Unfortunately, these are less effective for angioedema than for hives and are often totally ineffective for the non-itchy angioedema, in which histamine appears to play no significant role.

Other medications

Because the likelihood of side effects is greater, other drugs are usually reserved for when antihistamines fail to prevent angioedema, and are generally given under specialist supervision.

What is the outlook for someone with angioedema?

Angioedema eventually disappears in most people. It may reappear following an infection, when you are under stress or for no particular reason that can be identified. Occasionally it is a recurrent problem throughout life.

Learn more

The following links provide further information about angioedema. Be aware that websites from other countries may have information that differs from New Zealand recommendations.   

Angioedema NHS, UK

References

  1. Angioedema Australasian Society of Clinical Immunology and Allergy (ASCIA), 2019
  2. Angioedema DermNet NZ, 2006
Credits: Health Navigator Editorial Team.