Hereditary Angioedema (HAE) Triggers & Diagnosis

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HAE Triggers

HAE attacks may follow triggers that commonly include trauma and stress (physical and, to some degree, emotional). Attacks have also been associated with estrogen sensitivity, oropharyngeal surgery, dental procedures and intubation.1 3

HAE Diagnosis

Despite the early onset of HAE attacks, many patients may not be formally diagnosed for many years. This is because the disease is so rare and because external HAE symptoms are initially misdiagnosed as allergic reactions. Internal swellings are often misdiagnosed as acute abdomen and lead to unnecessary surgery. HAE is typically diagnosed after the patient has been suffering with symptoms for more than 13 years.6 8

HAE is caused by either a reduction in the amount of C1-INH or a reduction in the activity of this protein. In addition, levels of C4 complement protein are only normal in <1% of HAE patients between attacks.10 Therefore, HAE type 1 is diagnosed by finding decreased levels of C1-INH and C4. HAE type 2 is diagnosed by finding decreased levels of C4 and a reduction in C1-INH activity. Normal levels of C4, normal levels of C1-INH, and normal C1-INH activity may indicate another form of angioedema.1 9-10

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