HAE Attack Triggers

Know them to avoid attacks

Most HAE attacks occur spontaneously with no apparent reason. Some triggers have, however, been documented in studies of HAE.

Documented HAE attack triggers are:

  • Anxiety
  • Stress
  • Minor trauma
  • Surgery
  • Illnesses such as colds and flu

There are two subtypes of HAE based on the underlying genetic defect in the control of the blood protein C1-esterase inhibitor (C1INH) – and a third type HAE with normal C1INH. These angioedemas may share many of the same attack triggers.

Patients have also reported attack triggers that has not yet been documented in studies – these include:

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    Physical activities

    Patients have reported swelling in their extremities (hands and feet) following typing, prolonged writing, pushing a lawn mower, hammering, shoveling, and other physical activities.

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    Physical trauma

    HAE attacks may also be caused by physical trauma, such as surgery, may also trigger HAE attacks, in any part of the body. The trauma associated with dental procedures is particularly dangerous for HAE patients because it can increase the chances of airway (throat) swelling.

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    In women, menstruation and pregnancy seem to have a major effect on HAE. Many female patients report an increase in the number of attacks during their menstrual periods. During pregnancy, some women note an increase in the frequency and severity of attacks, while others have reported a decrease. The estrogen in contraceptives and hormone replacement therapy can trigger an increase in the frequency and severity of HAE attacks.

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    ACE Inhibitors

    Angiotensin Converting Enzyme Inhibitors (ACE Inhibitors) are prescribed to treat high blood pressure. Ace Inhibitors are known to cause bouts of angioedema in patients with normal C1 inhibitor levels. Because ACE inhibitors are believed to also be responsible for causing HAE swelling in C1 inhibitor deficient patients, specialists caution that these drugs should never be prescribed to HAE patients.

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