Patient Care - Allergy & Immunology - October 2007 - (Page 14)

I Angioedema Worldwide, the prevalence of hereditary angioedema is estimated at 1 in 50,000-150,000 persons. Approximately 15% of the US population is believed to be affected by recurrent episodes of angioedema. Women have been thought to have higher rates of hereditary angioedema, although this may be true mainly for type 3 hereditary angioedema. The occurrence of ACE-inhibitor angioedema is probably higher than the typical rates, listed as 0.1%-0.2%. Results of the Omapatrilat Cardiovascular Treatment Assessment Versus Enalapril (OCTAVE) trial, which included over 25,000 patients, showed rates of 0.68% for enalapril and 2.17% for omapatrilat. Additionally, the rates of angioedema were much higher than previous estimates in the specific groups of smokers (3.93%) and African Americans (5.54%).4 Differential diagnosis Many conditions may present in similar fashion to angioedema, although most have specific clinical characteristics that allow accurate diagnoses. Conditions that may cause similar symptoms include facial cellulitis, acute contact allergic or photodermatitis, Crohn’s disease of the mouth or lips, dermatomyositis, facial lymphedema, tumid discoid lupus, Ascher syndrome, Melkersson-Rosenthal syndrome, and superior vena cava syndrome.5 Hereditary angioedema Hereditary angioedema (HAE) is characterized by random swelling of the hands and feet, and frequently the face, tongue, and genitalia. Some patients present with severe abdominal pain secondary to bowel wall swelling. This pain is usually spasmodic with each peristaltic wave. An attack can last from several hours to several days and is generally not life-threatening unless it involves the airway, with asphyxiation being the leading cause of death. Several exacerbating factors have been identified including trauma, heat, cold, and emotional stress (angioneurotic). HAE is often not recognized when GI or other less obvious symptoms are the predominant features. Hereditary angioedema is an autosomal dominant disorder of C1 esterase inhibitor deficiency. The gene has been mapped to chromosome 11. Type 1 is characterized by low levels of normal functioning C1 inhibitor protein (85% of patients with HAE), while in type 2 the concentration of this protein is normal but is functionally impaired (15% of patients with HAE). C1 esterase inhibitor is a serine protease, and it controls the activity of the complement system. Failure of C1 inhibitor leads to unchecked activation of the C1 with consumption of complement components C2 and C4 and production of vasoactive peptides and vasodilation. The kallikrein system is also unchecked, which results in the production of bradykinins causing angioedema.6 Article at a glance I Angioedema is the transient swelling of areas in the deep dermis or SC tissue of the skin, mucosal membranes, or both. Angioedema is rare but potentially life threatening. Hereditary angioedema (HAE) may present predominantly with GI symptoms and can present a challenging diagnosis. Acquired angioedema (AAE) is a rare condition that is set apart from HAE by the absence of a family history of angioedema. The clinical presentation is the same and consists of painless, nonpruritic swelling of the skin and mucosal surfaces. Prompt treatment of AAE can prevent morbidity and death. ACE-inhibitor-associated angioedema is likely more common than previously thought. Angioedema from allergic reactions is the most commonly seen form of angioedema and often manifests in association with urticaria. Angioedema-associated eosinophilia (Gleich’s syndrome) is a rare form that is also associated with severe swelling of the face, lips, mouth, tongue, and extremities. I I I I I 14 PATIENT CARE ALLERGY & IMMUNOLOGY www.patientcareonline.com http://www.patientcareonline.com

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Patient Care - Allergy & Immunology - October 2007 Research Digest Contents Medicine in the News When to Suspect Celiac Disease and How to Proceed From There Averting Angioedema’s Potentially Dire Consequences Is There a Role for Leukotriene Receptor Antagonists in Treating Allergic rhinitis? Clinical Clips Dermatology Case Challenge Classified Advertising

Patient Care - Allergy & Immunology - October 2007

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