Hereditary angioedema: New therapeutic options for a potentially deadly disorder

In 1888, Sir William Osler provided a medical description of angioedema (AE) that distinguished an inherited form of the disease[1]. His description was the first to provide full clinical details. Seventy-five years later, Donaldson and Evans described patients with clinical features similar to those first described by Osler. The authors demonstrated a deficiency of C1 esterase inhibitor in the blood of these patients, although the extent of the deficiency was not able to be determined. Today, the biochemistry of the disease is better understood, but clinicians have low awareness of hereditary AE (HAE) and other types of non-allergic AE. Therefore, HAE is frequently undiagnosed. Approximately 50% of patients will be symptomatic by age 10[2]. However, accurate diagnosis may be delayed by decades[2]. For many, the disease results in multiple emergency department visits per year,[3] and for those patients with abdominal symptoms, one third may be subjected to inappropriate medical intervention due to misdiagnosis[4]. The fear of death from asphyxiation is an unfortunate but common part of life for many patients with HAE because of the risk of laryngeal swelling.New medications are available for prophylaxis and acute treatment of patients with HAE. These new medications offer targeted actions that reduce the potential for long-term adverse effects, such as those experienced with long-term androgen exposure, and they have quick onset action, making them the best choice for acute treatment. Increased awareness of HAE symptoms, of available diagnostics, and of available treatments among clinicians will help reduce time to diagnosis and improve disease management. The following discussion will help clinicians identify HAE and choose among available therapies.HAE affects 1:10,000 to 1:50,000 people and is caused by mutations in the C1 inhibitor gene[5]. The C1 inhibitor gene is located on chromosome 11, and multiple mutations resulting in C1 inhibitor deficiency have been id