While there’s often no clear cause for an attack of hereditary angioedema (HAE), certain activities, events, or situations are known to trigger attacks. These triggers include some physical activities, trauma, stress, and certain medications.

It’s not always possible to avoid HAE triggers, but understanding and anticipating them can help you take control of your HAE.

Physical activities

Physical activities that create repeated pressure are known to trigger attacks in many people with HAE. These triggers include foot swelling from standing in one place for a long time or hand swelling from gripping a tool. The attack usually occurs in the same part of your body as the triggering event.

Other repetitive activities known to cause HAE flare-ups include:

  • typing
  • mowing the lawn
  • shoveling
  • hammering

Some patients may also have an attack with excessive exposure to sun, cold, or water. Other environmental factors that can cause an attack include insect bites or stings, pollen, animal dander, and exposure to latex.

Stress and trauma

A variety of physical and emotional traumas can trigger attacks anywhere in the body. Dental work is a special concern because a flare-up around the face or throat could lead to airway swelling.

Trauma-related triggering events can include:

  • emotional stress
  • fatigue
  • infections
  • surgery
  • dental work
  • tongue or facial piercing
  • illness

Hormonal changes

Hormone fluctuations may lead to HAE attacks. Some women report an increase in attacks during their menstrual periods. Pregnancy can also affect HAE flare-ups. Some women have more attacks during pregnancy, but others may notice a reduction in attacks. Hormone replacement therapy or estrogen-based birth control can also make HAE attacks more frequent or severe.


Blood pressure medications that contain ACE inhibitors can worsen HAE attacks. If you have HAE and need blood pressure medication, your doctor will work with you to prescribe an alternative that doesn’t contain an ACE inhibitor. Before you start any new medication, it’s best to discuss it with an HAE specialist.


Some people with HAE are sensitive to certain foods, such as:

  • seafood
  • shellfish
  • nuts
  • eggs
  • milk


Certain medications may also trigger an attack of HAE. Some of the more common medications include:

  • Aspirin
  • NSAIDs
  • antibiotics
  • blood pressure medications, especially
    ACE inhibitors
  • oral contraceptive agents
  • blood transfusions or medications that
    have been derived from serum

Once you understand what triggers your HAE, do your best to avoid those events. For example, getting vaccinated for influenza prevents airway infections that may lead to an attack. Good daily dental habits reduce your need for dental surgery. If you’re stressed or fatigued, talk to your doctor about lifestyle changes you can make.

If you know you’ll need surgery or extensive dental work, you may wish to undergo short-term treatment with preventive medication. There are a couple of options for preventive treatment.One is taking a high dose of androgen therapy before and after surgery. Another option is taking a concentrated C1 inhibitor in the hours right before surgery.

Even if you undergo preventive treatment, “breakthrough” attacks are still possible. It’s always important to have on-demand medication available and a plan for how to administer it.

The U.S. HAE Association recommends keeping a paper or electronic log of every attack, whether it’s mild or severe. Logging your attacks will help you and your doctor monitor your treatment plan and understand what triggers your attacks.

The log should contain a description of your attack, what you did for treatment, and how you responded. You doctor can help you decide on a recording system that works best for you.

By anticipating and being prepared to treat HAE flare-ups, you can manage your HAE and live a full and active life.