Angioedema is self-limited, localized subcutaneous (or submucosal) swelling, which results from extravasation of fluid into interstitial tissues. Angioedema may occur in isolation, accompanied by urticaria, or as a component of anaphylaxis.

The clinical features, diagnosis, differential diagnosis, and management of angioedema will be reviewed here. The pathogenesis and causes of angioedema are discussed separately.

The goals of emergency treatment of angioedema are to prevent spontaneous eruption, to maintain a patent airway if eruption does occur, and to stop progression of disease. Laryngeal edema may occur rapidly. In these cases, a definitive airway such as an endotracheal tube should be established. If the airway cannot be effectively secured with an endotracheal tube, a surgical airway is indicated, usually in the form of an emergency cricothyrotomy. Life-threatening airway obstruction (if swelling occurs in the throat) and anaphylactic reactions are possible complications. Treatment of angioedema includes histamine blockers (H1 and H2), steroids, and, in those with severe symptoms, epinephrine (intramuscular or subcutaneous). However, hereditary angioedema (HAE) is generally refractory to treatment with these drugs. 

Avoiding particular substances or activities that trigger your symptoms may help reduce your chances of experiencing swelling.

For example, if you're allergic to a certain type of food, it can help to check the ingredients in food you buy and be careful when eating out.

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. 

If you have hereditary angioedema, there are a number of medicines available that may help prevent the swelling, or stop it from happening repeatedly.

They include:

• plasma kallikrein inhibitors, such as berotralstat and lanadelumab
• androgenic hormones, such as danazol and oxandrolone

Certain blood pressure medicines called angiotensin-converting enzyme (ACE) inhibitors can also cause flare-ups that can happen quickly. Even if you’ve been taking ACE inhibitors for a long time, sudden reactions can still happen.

Hereditary angioedema (HAE): This is rare. It happens when your body doesn’t make enough of a blood protein called C1 esterase inhibitor. That lets fluid from your blood move into other tissues, which brings swelling.

You’ll usually have your first bout of this before you turn 12 years old. You may pass the condition on to your children.