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 of an accumulation of fluid. It tends to affect areas with loose areas of tissue, especially the face and throat, as well as the limbs and genitals.
The condition may be mild, but if it progresses rapidly, or if it affects the throat, it can cause asphyxiation. This is a medical emergency.
Angioedema is 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.
Types of angioedema
An allergic reaction can lead to swelling in the deeper layers of the skin.
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 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.
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.
Signs and symptoms
The swelling deep inside the skin can affect the patient's hands, genitals, feet, the lining of the throat and bowel, and the face.
The swelling can affect loose folds of skin.
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.
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.
If the cause is hereditary, the patient may receive a concentrate of the the C1 inhibitor, the protein they are missing, and fresh frozen plasma.
Where appropriate, identifying and avoiding the allergen that leads to angioedema is key to preventing the occurrence of this condition.