Angioedema is the rapid edema, or swelling, of the area beneath the skin or mucosa. It is normally an allergic reaction, but it can also be hereditary.
The swelling happens because fluid accumulates. It tends to affect areas with loose areas of tissue, especially the face and throat, as well as the limbs and genitals.
It can be fatal, with 5,768 deaths as a result of angioedema recorded between 1979 and 2010.
Angioedema is a swelling of the area beneath the skin, similar to urticaria, or hives.
However, urticaria affects only the upper dermis, or top layer of skin. Angioedema affects the deeper layers, including the dermis, subcutaneous tissue, the mucosa, and submucosal tissues.
It is not uncommon to have both urticaria and angioedema at the same time.
The treatment for angioedema depends on the cause, but the most important action is to ensure a free airway. This means that in an emergency, a breathing tube might be placed for safety.
An allergic reaction may be treated with epinephrine, which is the drug in an EpiPen. Other medications include antihistamines and corticosteroids.
Where appropriate, identifying and avoiding the allergen that leads to angioedema is key to preventing the occurrence of this condition.
The cause of angioedema depends on its type, as follows:
- Insect bites, contact with latex, and some medications, such as penicillin or aspirin can trigger allergic angioedema.
- Certain medications, such as angiotensin-converting enzyme (ACE) inhibitors, can lead to drug-induced angioedema.
- A gene that causes a tendency to have low levels of a particular protein in the blood can be inherited. This, in turn, can lead to angioedema.
Other triggers for episodes include pregnancy, contraceptive pills, infection, or trauma. Patients are usually effectively treated with medication. Episodes may be severe and require hospitalization.
The cause may not be identified in some people with angioedema.
The swelling deep inside the skin can affect the patient's hands, genitals, feet, the lining of the throat and bowel, and the face.
Signs and symptoms tend to appear suddenly and rapidly. They may remain for up to 3 days. If urticaria develops, it may be itchy.
In some cases, the swollen areas may feel hot and possibly painful.
Vision may also be affected.
Bronchospasm may occur if the lining of the throat and airways are affected. There may be breathing problems.
In severe cases, anaphylactic shock may occur, and this can be life-threatening.
Emergency medical treatment will be necessary if the person:
- suddenly develops symptoms of angioedema, like with an allergic reaction
- has breathing problems that are sudden or are worsening
- feels faint or dizzy, or if they faint or collapse
If the person knows they have an allergy, they may have an autoinjector, such as an EpiPen. They can use this while waiting for medical help.
There are four main kinds of angioedema: Allergic, idiopathic, drug-induced, and hereditary.
This is the most common type, and it usually affects those with an allergy to a type of food, a medication, venom, pollen, or animal dander.
In serious cases, there may be a severe allergic reaction known as anaphylaxis. The throat may swell, making it hard for the patient to breath. Blood pressure may fall suddenly. This is a medical emergency.
This type of angioedema is not chronic, or long-term. As soon as the individual identifies which item is causing the allergic reaction, they can avoid it.
According to the Merck Manuals, 30 percent of cases of angioedema that are seen in the emergency department are linked to the use of ACE inhibitors.
If angioedema stems from using an ACE inhibitor, a healthcare provider can prescribe a different type of blood pressure medicine.
Another common type of medication that can cause angioedema is the non-steroidal anti-inflammatory class of drugs (NSAIDS) such as ibuprofen or aspirin. These are common painkillers.
If a disease is idiopathic, the cause is unclear. In this case, the doctor may not be able to identify a specific cause for angioedema after looking at all of the usual causes.
Some types of angioedema are inherited. This means that several people in the family may have symptoms.
In the case of hereditary angioedema, there is a problem with the C1 inhibitor protein. The patient will have low blood levels of the protein C1-esterase inhibitor (C1-1NH protein).
In this type of angioedema, episodes of angioedema will come and go over time.
A doctor will normally be able to form a clear diagnosis of the type of angioedema from the appearance of the symptoms, a description of what may have triggered them, and by taking a family and medical history.
They will also check if a person is taking any medications linked to angioedema, such as ACE inhibitors.
For example, having been exposed to a common allergen before the occurrence of angioedema means that allergic angioedema is likely. The presence of hives will also point to this type.
Alternatively, a family history of angioedema may suggest that the presentation of angioedema is hereditary.
A person with angioedema may be referred for further tests to confirm the type. These may include:
- a skin prick test to confirm a link to possible allergies, in which the skin is pricked with a very small amount of the allergen that is suspected
- a blood test to see how the immune system reacts to a certain allergen
- a blood test to check for C1 esterase inhibitor, low levels of which suggest that the problem is hereditary
The most dangerous complication of angioedema is swelling of the throat and airways.
The condition is normally mild, but if it progresses rapidly, or if it affects the throat, it can cause asphyxiation. This will lead to the following signs:
- sudden or rapidly escalating breathing problems
- fainting or dizziness
This is a medical emergency. Call 911 immediately if you notice these signs.