Understanding HAE

What is hereditary angioedema (HAE)? What causes it?

HAE is a rare hereditary disease that causes swelling and pain in certain parts of the body. It can be life threatening if the swelling occurs in the throat.

People suffering from HAE have an abnormality in a gene that makes C1-INH (“C1 inhibitor”), a key protein in the blood. This defect leads to low levels, or poor functioning, of C1-INH. Research shows that C1-INH regulates and “turns off” various reactions in the body, and without proper levels of functioning C1-INH, blood vessels can leak fluid into the surrounding tissues, causing swelling (angioedema) and pain.

What are the symptoms of HAE? How serious are they?

HAE can cause swelling and pain in specific parts of the body (such as the hands, feet, throat, and face). Attacks are generally worse during the first 24 hours and gradually subside in severity over the following 2 to 5 days. The symptoms of HAE may mimic other types of medical conditions, such as allergic reactions or appendicitis.

Swelling in the throat may compromise the airways and can be life threatening. Swelling in the intestines may cause severe abdominal pain. Although the majority of the attacks are not life threatening, they can seriously affect quality of life.

Are your symptoms signs of HAE? Answer these questions

Use this guide to discuss your symptoms with your doctor

Are there different types of HAE?

There are two main types of HAE and one rare type. Type I HAE is caused by low levels of C1-INH. In type II HAE, levels are normal, but there is decreased functionality of the C1-INH protein. Another kind of HAE, HAE with normal functioning C1-INH (formerly known as type Ill), has been identified but it is extremely rare. In these patients, C1-INH levels are usually normal.

Learn more about the different types of HAE

How does a person get HAE? Will I pass it on to my children?

HAE is usually inherited, with the abnormal gene being passed down from a parent to a child. However, about 25% of HAE cases are caused by a new mutation in people with no familial history of HAE.

If someone with HAE has a child with a person without the condition, there is a 50% chance their offspring will inherit HAE.

How common is HAE?

HAE is quite rare. Only about 1 in 10,000 to 1 in 50,000 people has HAE.

How is HAE diagnosed?

HAE is diagnosed by taking a blood sample and measuring the level of C1-INH in the blood. Another important blood protein, called C4, is often used in screening tests as well.

The blood test should be done through an allergist or immunologist. They have access to labs that can accurately analyze your blood sample and quickly provide results.

Living with HAE

Are there any warning signs that I am going to have an attack?

Attacks are often unpredictable, but you may be able to sense their onset. Common warning signs include sudden mood changes, irritability, anxiety, extreme fatigue, rash, nausea, or a tingling sensation of the skin where the swelling will begin. Keep a journal of the warning signs you experience before an attack and share it with your doctor at each visit.

A hoarse voice, difficulty in swallowing, a feeling of tightness, and voice changes may be the first signs of a life-threatening laryngeal attack. People who experience these symptoms should get immediate emergency help.

Learn how to recognize and avoid your HAE triggers

If I have HAE, can I continue working, exercising, etc?

Once you and your doctor have a treatment plan in place you should be able to continue living normally. Be aware, though, that stress can aggravate HAE and lead to more attacks. If you continue experiencing attacks, tell your doctor. Adding a preventive therapy may help reduce the frequency of your attacks.

Where can I find out about support groups for HAE families?

Although HAE is a rare disorder, there are many support groups available. Numerous patient organizations and discussion boards are available online to provide information and support to families with HAE.

Get the support you need

What can trigger an HAE attack?

Although the actual causes of HAE attacks have not been clearly established―and vary from patient to patient―some patients report an increased number of attacks during and after stressful situations. By tracking your symptoms carefully and keeping a journal, you can discover whether or not stress is a trigger for you.

Also, people may have sensitivities to various medications. Certain drugs, such as ACE inhibitors (for controlling blood pressure) and contraceptives containing estrogen, may trigger HAE attacks or increase attack frequency.

Learn how to recognize and avoid your HAE triggers

How do I travel with my medication(s)?

When traveling, keep your medication(s) in your carry-on bag, just in case you have an attack. The Transportation Security Administration allows you to travel with medically necessary liquids, even those in excess of 3.4 ounces (100 ml). You do not need to place them in a plastic, zip-top bag. Remove them from your carry-on bag so they can be screened separately from your belongings and inform the TSA officer that you have medically necessary liquids. You may want to call your local airport ahead of time to verify their policy.

It's also a good idea to bring along an HAE diagnosis letter from your doctor as well as an ID card. If you are going to be traveling to a country where English may not be understood, you may want to have them translated into the language of that country. If you cannot readily transport your current medication with you, ask your doctor to write a prescription for the appropriate HAE medication for the country you are visiting.

Visit the US Hereditary Angioedema Association for more information.

HAE Treatments

What should I do if I have an HAE attack?

A doctor who is an expert on HAE can help you determine what you should do when you have an attack. The prescribed course of treatment may depend on the location of the attack, the frequency of attacks, and the type of medications available to you.

Find an HAE specialist near you

People who experience symptoms of a laryngeal attack should get emergency help as soon as possible.

Learn about treatments

How is HAE treated?

HAE treatment can be divided into two categories: preventive therapy and acute (on-demand) therapy. Preventive therapy is ongoing treatment you take to prevent HAE attacks. Acute therapy is used to treat attacks as they happen, and can help reduce their severity and duration.

If you experience life-threatening, frequent, or life-altering attacks, you may be a good candidate for preventive therapy, in addition to using an on-demand therapy.

Talk to your doctor about your treatment options.

Learn more about treatments

What side effects might I have with treatment, and how do I manage them?

The side effects you experience will depend on the treatment option used, the dosage, and how the treatment is administered. It also depends on whether the treatment is for an acute attack or one used to prevent attacks.

Talk to your doctor about potential side effects based on your personal treatment and when you should call the doctor's office about a medical problem. Recording information in your HAE journal will help you and your doctor track your progress and effectively manage your disease.

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Hereditary Angioedema Association (HAEA)

Learn about the HAEA, a nonprofit organization dedicated to expediting US approval of safer and more effective HAE therapies.

Visit HAEA.org

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