Hereditary angioedema is a rare inherited disorder characterized by recurrent episodes of the accumulation of fluids outside of the blood vessels, blocking the normal flow of blood or lymphatic fluid and causing rapid swelling of tissues in the hands, feet, limbs, face, intestinal tract, or airway. Swelling of the gastrointestinal tract leads to cramping. These symptoms develop as the result of deficiency or improper functioning of certain proteins that help to maintain the normal flow of fluids through very small blood vessels (capillaries).

The aim of the EHA trial (Epidemiological Analysis for Hereditary Angioedema Disease) is to identify those patients whose presentations with recurrent abdominal pain may be as a result of this condition. HAE is exceptionally rare and is therefore not often considered as a diagnosis in patients with recurring abdominal pain. This trial therefore aims to assess the feasibility of using a dried blood spot sample in these patients to facilitate diagnosis. The overall objective is that this will prevent both further hospitalisations and further unnecessary investigations on these patients, and also provide answers to those patients who have no current cause for their recurrent issues.