The doctor will ask you questions about the attack. The doctor will note if the HAE attack happened with or without itching. Usually, this helps to tell whether the swelling was due to HAE or part of an allergic reaction.
Since HAE is rare and therefore diagnosing it may be difficult. This disorder may be hereditary but about a quarter of people with HAE have no family history of the condition. Sometimes, whether or not other family members have had history of this condition does not help that much with diagnosing HAE.
Patients will have a history of swelling for unknown reasons or unexplained belly aches with or without vomiting and diarrhea. Some may have had exploratory abdominal surgery, however no exact solution was reached.
Screening by laboratory testing should be done if the physician suspects the condition from the patient’s history or physical examination, or in case of a positive family history of HAE.
Measuring the C4 complement level is used as a screening test. A normal level makes HAE unlikely.
If the C4 complement level is low, laboratory analysis of blood samples or genetic testing is required to establish the diagnosis of HAE. There are two specific blood tests that confirm HAE:
- C₁-inhibitor quantitative (antigenic): available at Hamad Medical Corporation (HMC).
- C₁-inhibitor functional: not available (currently) at HMC.
The tests can be done more than once to be sure. Levels may be normal when a person isn’t having an attack at the time the test was taken.
