What Is Angioedema? What You Need to Know

What is the main cause of angioedema?

The main cause of angioedema is an allergic reaction or an immune system overreaction. Factors such as medications, infections, or genetic mutations can also contribute to the condition, causing swelling of the deep layers of the skin and tissues beneath, usually around the face, lips, throat, and genitals.

Get started
Wyndly Allergy

Beat your allergies forever.

Get Started With Wyndly

Angioedema is a medical condition characterized by swelling of the deep layers of the skin and tissues beneath it, usually around the face, lips, throat, and genitals. It may also be accompanied by other symptoms such as difficulty breathing, itching, and pain.

Types of Angioedema

There are several types of angioedema, each with its distinct causes and symptoms. Here is an in-depth guide to the different types of angioedema.

Allergic Angioedema

Allergic angioedema is the most common type of angioedema and can be triggered by a wide range of allergens, including foods, medications, insect stings, and latex. When you encounter a trigger, your body releases histamine and other chemicals into your bloodstream. These chemicals cause your blood vessels to widen and leak fluid into the tissues, resulting in swelling.

Symptoms usually develop rapidly and can include swelling of the face, lips, tongue, throat, or eyes, urticaria (hives), and difficulty breathing. Allergic reactions can be mild, moderate, or severe. Mild reactions may cause only a small amount of swelling. Moderate reactions may cause more widespread swelling and can interfere with breathing. Severe reactions can be life-threatening and require immediate medical attention.

Hereditary Angioedema (HAE)

HAE is a rare genetic disorder caused by a deficiency of C1-inhibitor, a protein that helps regulate the immune system. Stress, trauma, or hormonal changes can trigger HAE attacks. The most common symptom of hereditary angioedema is recurrent episodes of swelling in the face, hands, feet, abdomen, genitals, or throat. These episodes can last for days or weeks and can occur without warning.

Hereditary angioedema can also cause abdominal pain, diarrhea, nausea, and vomiting due to intestinal blockage from abdominal swelling. In some cases, hereditary angioedema can also cause difficulty breathing due to throat swelling. Hereditary angioedema may require lifelong treatment with C1-INH replacement therapy.

Acquired Angioedema (AAE)

AAE is a rare type of angioedema caused by the production of autoantibodies. These antibodies interfere with C1-inhibitor function, causing C1 inhibitor deficiency. AAE is usually associated with autoimmune disorders such as lupus or rheumatoid arthritis, but it can also occur in people with chronic infections or liver disease.

Symptoms often appear suddenly and can be severe enough to require hospitalization for treatment with intravenous fluids and medications like steroids or epinephrine. Long-term management typically involves lifestyle modifications such as avoiding certain foods or activities that may trigger flare-ups of AAE. It may also involve taking medications like antihistamines, immunosuppressants, or blood thinners, depending on the severity of the condition.

Drug-induced Angioedema

Drug-induced angioedema (DIA) occurs when an individual takes a specific drug or medication that triggers an allergic reaction. The allergic reaction then leads to swelling around the face, mouth, tongue, lips, hands, feet, and other parts of the body.

Common drugs that cause DIA include penicillin, aspirin, and other nonsteroidal anti-inflammatory drugs (NSAIDs). Angiotensin-converting enzyme inhibitors (ACE inhibitors) for high blood pressure, chemotherapy drugs for cancer treatment, and anticonvulsants for seizure control can also contribute to the condition. DIA can also occur after vaccination or bee venom exposure. Symptoms can range from mild to severe and can occur within hours or days of taking the medicine.

Idiopathic Angioedema

Idiopathic means the underlying cause is unknown. Idiopathic angioedema can be acute (lasting less than six weeks) or chronic (lasting longer than six weeks). This type of angioedema typically causes recurrent episodes of facial swelling but can also affect other parts of the body, such as the hands, feet, abdomen, genitals, or throat. These episodes usually last for a few days but can last up to several weeks. Idiopathic angioedema does not typically cause difficulty breathing. However, it may rarely cause abdominal pain, diarrhea, nausea, or vomiting.

What Causes Angioedema?

Angioedema can be caused by a variety of different factors, including allergies, medications, infections, and other underlying medical conditions. It’s important to know which you have so you can get the right treatment plan.


Allergic reactions are one of the most common causes of angioedema. When an allergen (such as pollen or animal dander) enters the body, it triggers an allergic reaction. This reaction releases chemicals called histamines, which cause the swelling and inflammation associated with angioedema.


Some medications can also cause angioedema as a side effect. Common culprits include angiotensin-converting enzyme inhibitors (used to treat high blood pressure), nonsteroidal anti-inflammatory drugs (NSAIDs), and certain antibiotics. If you experience angioedema after taking medication, contact your doctor right away so they can adjust your treatment plan accordingly.


Certain infections can trigger angioedema in some individuals. These include respiratory infections such as strep throat and urinary tract infections and viral illnesses like mononucleosis or hepatitis B and C. If you have been diagnosed with any type of infection and experience sudden swelling or hives on your skin or mucous membranes (such as inside your mouth), seek medical attention immediately, as this could be a sign of severe allergic reaction or anaphylaxis.

Other Medical Conditions

In some cases, angioedema may be caused by an underlying medical condition such as lupus or thyroid disease. If you have been diagnosed with any type of autoimmune disorder or chronic illness and notice sudden swelling in areas such as your face or throat, contact your doctor right away for further evaluation and treatment options if necessary.

Hereditary Causes

In some cases, angioedema may be hereditary, which means that it runs in your family and is passed down from generation to generation through genes. Hereditary angioedema usually occurs without any known trigger but can sometimes be triggered by stress or strenuous activity.

How do Allergies Cause Angioedema?

Allergic angioedema is an immune system response triggered by exposure to an allergen. When an allergen comes into contact with antibodies in your system, your blood vessels can widen, resulting in symptoms like swelling. When swelling occurs in the deeper layers of the skin, you have angioedema.

To go a bit more into detail, when your body detects an allergen, your immune system produces IgE antibodies to fight the perceived threat. These antibodies attach themselves to mast cells in various parts of the body, including the skin, airways, and digestive system.

When the allergen comes into contact with the IgE antibodies, the mast cells release histamine and other chemicals, which cause blood vessels in the affected area to widen and become leaky. This process results in swelling, redness, itching, and other symptoms associated with allergic reactions.

In the case of angioedema, the swelling occurs in the deeper layers of the skin and subcutaneous tissues, affecting areas such as the face, lips, tongue, throat, and genitals. This swelling can be rapid and severe and can cause difficulty breathing or swallowing, making it a potentially life-threatening condition.

Signs and Symptoms of Angioedema

Apart from swelling, angioedema can accompany other symptoms, such as difficulty breathing or abdominal pain. Here are some signs and symptoms of angioedema:

  • Swelling: The most obvious sign of angioedema is swelling in the affected areas. The swelling is usually painless and may feel warm to the touch.
  • Redness and Itching: The affected areas may also be red and itchy. Itching can be mild to severe, and scratching can worsen the swelling.
  • Difficulty Breathing: Severe angioedema can cause swelling in the throat and airways, leading to difficulty breathing, shortness of breath, or wheezing. This can be a medical emergency and requires prompt treatment.
  • Difficulty Swallowing: Swelling in the throat can also make it difficult to swallow food or liquid.
  • Abdominal Pain: In some cases, angioedema can affect the digestive tract, leading to abdominal pain, cramping, and diarrhea.
  • Fatigue and Malaise: Some people with angioedema may feel tired, weak, or have a general feeling of being unwell. Sometimes it may lead to dizziness or fainting.

If you experience any of these symptoms, seek medical attention promptly, as severe swelling can lead to life-threatening complications.

Is Angioedema Contagious?

No, angioedema is not contagious. It is a non-infectious condition, so it can't be transmitted from one person to another through direct or indirect contact. While some underlying conditions that may cause angioedema can be contagious, angioedema itself cannot be transmitted from one person to another.

How Can I Prevent Angioedema?

Preventing angioedema depends on the underlying cause. Since there are many causes, there isn’t one method to prevent the condition. However, there are several steps you can take to minimize the risk of developing angioedema. Here are a few tips:

  • Avoid known triggers: If you have a history of angioedema or allergic reactions, try to avoid known triggers. For example, if you have a food allergy, avoid eating that particular food. If you are allergic to insect stings, take precautions to avoid getting stung.
  • Take medication as prescribed: If you're taking medications that may cause angioedema, follow your doctor's instructions carefully. Do not stop or change the dose of any medication without consulting your doctor.
  • Manage stress: Stress can exacerbate angioedema, so managing stress levels is important. Exercise regularly, practice relaxation techniques, and seek support from friends, family, or a therapist.
  • Be prepared: If you have a history of severe angioedema or anaphylaxis, always carry an epinephrine auto-injector (EpiPen) with you. Ensure your friends, family, and coworkers know how to use it in an emergency.
  • Seek medical attention promptly: If you experience angioedema or anaphylaxis symptoms, seek medical attention promptly. Delayed treatment can be life-threatening.

Remember, prevention is key when it comes to angioedema. By avoiding known triggers and managing underlying medical conditions, you can minimize the risk of developing angioedema.

When to See a Doctor

Here are some signs you should see a doctor:

Difficulty Breathing

If you experience swelling in your throat or airways, you may have difficulty breathing, shortness of breath, or wheezing. This can be a medical emergency and requires immediate treatment.

Rapid or Severe Swelling

You may experience rapid or severe swelling that affects your face, lips, or eyes. This can be a sign of angioedema and requires medical attention to prevent complications.

Swelling After Taking Medication

If you develop swelling after taking medication, seek medical attention promptly. Some medications can cause angioedema, and your doctor may need to adjust your dose or prescribe a different medication.

Swelling After Exposure to an Allergen

If you have a known allergy and develop swelling after exposure to an allergen, seek medical attention promptly. This can be a sign of anaphylaxis, a severe allergic reaction that requires immediate treatment.

Swelling That Does Not Improve

See a doctor if you have swelling that does not improve with self-care measures, such as applying ice or taking antihistamines. This can be a sign of an underlying medical condition that requires treatment.


When it comes to diagnosing angioedema, work with a professional healthcare provider who will perform a thorough medical evaluation and order the appropriate diagnostic tests. A healthcare provider may use a combination of the following tests to diagnose angioedema.

Allergy Test

Skin prick tests involve pricking your skin with a needle and exposing it to different allergens, such as pollen or dust mites. You can opt to get an at-home allergy test from Wyndly, which can help identify what allergens you're allergic to without leaving your home.

The test uses a blood sample to test for allergen-specific immunoglobulin E (IgE) antibodies. Allergy tests should be used in conjunction with other diagnostic tests to diagnose angioedema accurately.

Blood Test

A blood test can detect elevated levels of immunological activity, which can be a sign of an allergic reaction or an autoimmune disorder. The blood test can also measure the levels of C1 esterase inhibitor protein (C1-INH), which can help identify hereditary angioedema. A deficiency of C1-INH protein can cause hereditary angioedema.

Genetic Test

Genetic testing can identify specific gene mutations that cause angioedema. The specific gene mutations that cause type l and ll angioedema can be found on the SERPING1 gene, while mutations on the F12 gene can be identified for type lll angioedema.


Treatment options for angioedema depend on the underlying cause, severity, and frequency of symptoms. Here are some options.


Antihistamines are a common treatment for mild to moderate angioedema caused by an allergic reaction. They work by blocking the effects of histamine. Over-the-counter antihistamines, such as diphenhydramine (Benadryl) or loratadine (Claritin), may be effective for mild symptoms, while prescription-strength antihistamines, such as fexofenadine (Allegra) or cetirizine (Zyrtec), may be needed for more severe symptoms.


Epinephrine is a medication that can treat severe angioedema caused by an allergic reaction. It works by constricting blood vessels and relaxing airway muscles, which can help reduce swelling and improve breathing. Epinephrine is typically administered through an auto-injector, such as an EpiPen, and should be used as soon as symptoms of an allergic reaction occur.


Corticosteroids are a type of anti-inflammatory medication that you can use to treat angioedema caused by an autoimmune disorder or an unknown trigger. They work by reducing inflammation in the body and suppressing the immune system.

C1 esterase inhibitor (C1-INH) replacement therapy

C1-INH is a protein that regulates the complement and coagulation systems in the body. A deficiency of C1-INH can cause hereditary angioedema. C1-INH replacement therapy involves replacing the missing C1-INH protein through intravenous (IV) infusion. This treatment can help prevent or reduce the frequency and severity of hereditary angioedema attacks.

Sublingual Immunotherapy

Sublingual immunotherapy (SLIT) is a type of allergy treatment that involves placing allergens under the tongue to help the body build up a tolerance to them over time. You can use SLIT to treat the underlying allergies that cause angioedema.

Take Our Allergy Assessment

Looking to gain a better understanding of your allergy sensitivities? Wyndly's at-home allergy test provides a simple and convenient way to identify your specific allergens and develop a personalized plan to manage your allergies.

If you're ready to take control of your allergies, take our quick online assessment today.

Is Wyndly right for you?

Answer just a few questions and we'll help you find out.

Get Started Today