HAE is an autosomal dominant disorder that is most frequently caused by a deficiency or dysfunction of the protein C1 esterase inhibitor (C1-INH). This inhibitor regulates several inflammatory pathways, and a failure to control production of bradykinin in these patients results in episodes of cutaneous or mucosal edema.1 HAE is characterized by recurrent and unpredictable edema of the extremities, face, genitalia, trunk, gastrointestinal tract, or upper airway. It can be life-threatening if the larynx is involved, as occurs in approximately 2% of cases.
HAE affects approximately 1 in 50,000 worldwide, with a mean age of symptom onset of 8 to12 years.1 Many patients have a known family history of HAE, but up to 25% have a de novo C1-INH mutation.2 Many are undiagnosed, and thus have a higher risk of mortality by asphyxiation.
Because it is rare, HAE may not be considered in the initial differential diagnosis. Also, the presentation may mimic that of an allergic reaction, prompting clinicians to give epinephrine, antihistamines, and/or corticosteroids, which will have little effect on an HAE attack and prolong both diagnosis and appropriate treatment.3 HAE patients commonly undergo unnecessary medical procedures and see multiple physicians before a diagnosis is made.4,5 Correct diagnosis is critical for appropriate treatment, which can be classified into acute treatment, short-term prophylaxis, and long-term prophylaxis.3
As treatment for HAE is rapidly evolving, it is important for all healthcare professionals who treat HAE to stay abreast of current treatment options, including home-based options. Historical treatments are slowly being replaced by more efficacious agents such as C1-INH replacements, bradykinin-receptor antagonists, and kallikrein inhibitors.
1. Longhurst H, Cicardi M. Hereditary angio-oedema. Lancet. 2012;379(9814):474-481.
2. Zuraw BL. Clinical practice. Hereditary angioedema. N Engl J Med. 2008;359(10):1027-1036.
3. Gower RG, Lumry WR, Davis-Lorton MA, Johnston DT, Busse PJ. Current options for prophylactic treatment of hereditary angioedema in the United States: patient-based considerations. Allergy Asthma Proc. 2012;33(3):235-240.
4. Riedl M. Hereditary angioedema therapies in the United States: movement toward an international treatment consensus. Clin Ther. 2012;34(3):623-630.
5. Toscani M, Riedl M. Meeting the challenges and burdens associated with hereditary angioedema. Manag Care. 2011;20(9):44-51.