Hereditary angioedema (HAE) is a rare, debilitating, potentially life-threatening genetic disease characterized by recurring attacks of edema (swelling) in various parts of the body, including the upper airways (throat or larynx), hands, feet, face, and abdomen (stomach). HAE attacks affecting the hands face, and feet can be severely disfiguring, whereas abdominal attacks, caused by swelling of the intestinal wall, are marked by severe stomach pain. Attacks that affect the airway/throat can be life-threatening, as swelling can constrict the larynx or enlarge the tongue which can quickly lead to suffocation.

Patients can sometimes link specific situations that occur in their lives, such as stress, infections or even the consumption of certain foods, that ’trigger’ the development of edema, although often no trigger mechanism can be clearly identified.  In most cases, the edema develops gradually over a period of 12-36 hours and then subsides spontaneously within 2-5 days.  It has been reported that the time from the onset of symptoms to a full-blown attack ranges from twenty minutes to as long as fourteen hours and that patients experience an average of twelve attacks per year.

The development of edema does not affect one site consistently and, the site which is affected may vary from one attack to the next.  This makes it impossible for patients to predict which site will be affected by the next attack. The frequency, duration and severity of the edema may also vary considerably from one attack to the next. Most patients have an average of one episode of swelling per month; however, some patients may experience weekly attacks while others have only one or two attacks per year.

The disease places extraordinary strain on patients. Depending on the severity of attacks, just one episode per month may prevent the patient from having a normal social and professional life for several days at a time. There is also the constant worry about the next, possibly life-threatening episode (one which affects the airway or larynx). As HAE is a rare disease, many healthcare professionals are unfamiliar with the condition and it is often several years before patients are diagnosed correctly and referred to a physician familiar with treating their disease and it’s management.